Composition comprising glycosphingolipids

Abstract

A composition comprising one or more compounds of formula (1), or salts thereof: (1) wherein R1 is a C13-C17 alkyl chain; R2 is a C15-C19 alkyl chain, preferably C18; and R3 is a glycosyl moiety selected from Neu5Acα2-3-Galβ1-4-Glcβ1-, or Neu5Acα2-8-Neu5Acα2-3- Galβ1-4-Glc β1-. Child nutritional formulas containing the composition are also provided.

Description

[0001] DESCRIPTION COMPOSITION COMPRISING GLYCOSPHINGOLIPIDS Filed of the Invention This invention relates to a composition comprising one or more synthetic glycosphingolipids, to child nutritional formulas which contain said composition and to uses of said synthetic glycosphingolipids and nutritional compositions comprising thereof for treatment of dysbiosis and enhancing growth and development of infants. Background of the Invention Breast feeding is recommended for all infants as human milk contains all the essential nutrients for optimal growth and development of the infant. Besides of providing nutrients, human milk is also a major factor that form the infant gut microbiome community that is crucial for infant healthy growth and development (Yao, Y. et al. The role of microbiota in infant health: from early life to adulthood. Front. Immunol.12, art.708276 (2021) https: / / doi.org / 10.3389 / fimmu.2021.708472). Human milk is broadly composed of water, carbohydrates, lipids, proteins, vitamins, and minerals. It has now been widely recognized that a particular carbohydrate fraction of human milk, human milk oligosaccharides (HMOs), that can only be metabolized by certain gut commensals, ensure proper gut microbiome establishment and infant development The lipid fraction of human milk occurs mostly as triacylglycerols which are dispersed throughout the milk in globules. The globules are encapsulated by a tri-layer membrane called the milk fat globule membrane. The triacylglycerol fraction provides about 98% of milk lipids in human milk and delivers more than 50% of the energy intake of the new-born infant. The remaining 2% of milk lipids includes components of the milk fat globule membrane such as polar lipids, cholesterol (including free and cholesteryl esters), mono- and di-glycerides, and free fatty acids. Although a relatively minor fraction in terms of abundance, the milk fat globule membrane component is nutritionally important by serving as a source of cholesterol and polar lipids. The role of human milk lipid fraction on the infant gut microbiota is poorly documented, but several lines of evidence point to a possible effect. Indeed, in vitro studies reported either bactericidal activities of milk lipids, including medium-chain fatty acids (MCFAs), sphingosine, and monoacylglycerols (Sprong RC, Hulstein MF, Van der Meer R. Bactericidal activities of milk lipids. Antimicrob Agents Chemother. (2001) 45:1298–301. doi: 10.1128 / AAC.45.4.1298-1301.2001). Accordingly, Nejrup et al. observed significant changes in infant fecal microbial communities (increased Lactobacillus and Bifidobacterium abundances and decreased Enterobacteriaceae abundance) cultured with selected HM lipids MCFA, monoacylglycerol, and / or sphingosine during anaerobic in vitro fermentation (Nejrup RG, Bahl MI, Vigsnæs LK, Heerup C, LichtTR, Hellgren L I . Lipid hydrolysis products affect the composition of infant gut microbialcommunities in vitro. Br J Nutr. (2015) 114:63–74. doi: 10.1017 / S0007114515000811 ). Human milk gangliosides could also participate in the shaping of the infant gut microbiota. They are glycosphingolipids consisting of a hydrophobic ceramide and a hydrophilic oligosaccharide chain and have been described as putative decoys that interfere with pathogenic binding. Infant formula enriched in ganglioside reduced E. coli counts and slightly increased bifidobacteria counts (+0.5 log / g feces) in preterm infant feces after 30 days. Likewise, several reports in mice indicated an effect of dietary bovine sphingolipids on microbiota composition. However, at present, there is no scientific reports documenting the beneficial effects of human milk gangliosides on the composition of infant gut microbiota. Gangliosides have also been shown to influence the expression of gut tight junction proteins, maintaining intestinal integrity during episodes of gut inflammation (Park et al, 2010, Journal of Pediatric Gastroenterology and Nutrition, 50, 321). It is also believed that the gangliosides play a critical role in the development of the infant’s central nervous system. The most abundant ganglioside in mature human milk is GM3, which has one sialic acid side-unit in its carbohydrate chain. The ganglioside GD3, which has two sialic acid units, is also present at relatively high levels in early-lactation milk but levels diminish to low levels with time. Unfortunately, breastfeeding is not always possible or practicable, and therefore there is a need for human milk substitutes. These substitutes usually take the form of starter infant formulas for new- born infants and follow-on formulas for infants of 6 to 12 months of age. Also, for infant having special needs, certain medical formulas are used. These formulas are typically produced using reduced-fat dairy products such as bovine skim milk, or fractions obtained from bovine skim milk. This means that, at best, these formulas contain levels of polar lipids and cholesterol which are significantly lower than the levels in human milk. However, many of these formulas are formulated with vegetable oils rather than bovine lipids. As a result, the milk fat present in many formulas is typically very low, although supplementation of milk fat is becoming more prevalent. Where formula is supplemented with bovine milk fat, it is often by using anhydrous milk fat, which contains cholesterol but not polar lipids. Even when bovine milk fats are used, bovine milk contains significantly lower levels of gangliosides and human milk. Therefore, when reconstituted, the resulting formulas still contain much less gangliosides than human milk. The infant nutrition industry has responded by incorporating bovine milk fat globule membrane fractions into infant formula (EP2211629). This enables the overall ganglioside levels of infant formulas to be brought closer to those in human milk. However, issues remain. In bovine milk, ganglioside GD3 is much more abundant than ganglioside GM3. As mentioned above, human milk contains greater amounts of ganglioside GM3. The difference in the ratio of GM3 to GD3 in human and bovine milk is likely due to their different biological and developmental requirements (Pan et al, 2000, Early Human Development 57, 25–31). Further, GM3 and GD3 are not single compounds but are collective names for groups of compounds with similar structures. In particular, the fatty acids attached to the sphingoid base of the ganglioside can vary in chain length. The fatty acid chain lengths in human GM3 and GD3 predominantly contain 20 or less carbon atoms while those in bovine milk predominantly contain 22 or more carbon atoms (Bode et al, 2004, J. Nutr.134: 3016–3020; Martín-Sosa et al, 2004, Lipids 39, 111–116). This difference has biological relevance. The fatty acid composition of gangliosides influences membrane fluidity and alters the formation of sphingolipid clusters in the cell membrane, which is important for cell– cell interactions, receptor–ligand interactions, and signaling pathways. Due to beneficial biological activities of dietary human milk gangliosides for infant growth and development (discussed above), these gangliosides are desired compounds to include in infant formulas to support healthy growth and development of not breast milk fed young children, especially in their very first months of postnatal life. Unfortunately, at present human milk identical gangliosides are not available in the amounts that could satisfy this demand. The industrial production of these gangliosides has not yet been set. Typically, gangliosides included in currently available infant formulas are gangliosides extracted from cow milk, which effects on infant health differ from human milk gangliosides (Bode et al, 2004 -see above). Summary of the invention In a first aspect, the invention relates to a synthetic compound of formula (1), or salt thereof: wherein R1is a C13-C17 alkyl chain; R2is a C15-C19alkyl chain, preferably C18; and R3is a carbohydrate moiety selected from: Neu5Acα2-3-Galβ1-4-Glcβ1-, or Neu5Acα2-8-Neu5Acα2-3-Galβ1-4-Glc β1-; for use in dietary or prophylactic treatment of dysbiosis in a young child, wherein the treatment stimulates colonization of beneficial bacterial species of phyla Actinobacteriota, Bacteroidota and / or Firmicutes in the gut of the young child and thereby promotes healthy functionality and maturation of the young child digestive and immune systems and the young child growth and development. In a second aspect, the invention relates to a nutritional composition comprising one or more synthetic compounds of formula (1). Various embodiments relating to these aspects of the invention are described throughout this specification and are illustrated by non-limiting examples. Description of the Figures Figure 1. Schematic outline of the study of the impact on metabolite production and microbiota composition in the gut of healthy infants stimulated by compositions of the present invention described in Example 7 and Example 8. Detailed Description of the Invention It has been surprisingly found that it is possible to produce, at scale and at reasonable cost, synthetic human milk-identical gangliosides, in particular GM3 and GD3, and compositions comprising said gangliosides. These compositions can contain other synthetic glycosphingolipids, such as lactosyl ceramide and / or glucosyl ceramide, which are also identical to those present in human milk. This enables the provision of child nutritional formulas which are closer in composition to human milk. By comprising gangliosides which are identical in structure to gangliosides in human milk, the composition is better tolerated by the infant or young child. Moreover, it has been surprisingly found that synthetic human milk-identical gangliosides of the invention and compositions comprising thereof stimulate colonization of the young child gut with beneficial bacterial species, such as species of phyla Actinobacteriota, Bacteroidota, Firmicutes, Proteobacteria and / or Verrucomicrobiota. The compounds and compositions surprisingly were particular efficient in promoting the colonization and growth of the following bacterial species: Bifidobacterium longum, Bifidobacterium breve, Bifidobacterium scardovii, Bacteroides caccae, Bacteroides uniformis, Bacteroides stercoris, Bacteroides xylanisolvens, Parabacteroides merdae, Faecalibacterium prausnitzii, Collinsella aerofaciens, Ruthenibacterium lactatiformans, Ruminococcus gnavus, Hungatella hathewayi, creating a relative abundance of said species in the young child microbiota composition. The mentioned microbiome species have been proven to be beneficial for healthy functionality and maturation of the young child digestive and immune systems and the young child healthy growth and development (Castanys- Muñoz, E., et al.2016 Building a Beneficial Microbiome from Birth Adv Nutr.2016 Mar; 7(2): 323–330; doi:10.3945 / an.115.010694). In particular, by promoting colonization and growth of above mentioned bacteria, the compounds and compositions of the invention - support and / or promote maturation of the immune system of the child; - reduce colonization of the child gut by pathogenic bacterial species and / or decrease the risk of such colonization; - maintain and / or improve the child gut barrier integrity; - provide the child with nutrients and metabolites essential for the child growth, development and maturation, such as vitamins, amino acids, short-chain fatty acids, by stimulating colonization of the child gut with beneficial bacteria (such as mentioned above) and promoting their growth within child microbiome. These beneficial bacteria are synthesizers of nutrients and metabolites essential for the child growth, development and maturation. By stimulating beneficial bacteria colonization of the gut of young children upon dietary supplementation the compounds and compositions of the invention create, maintain and recover, when necessary, a healthy gut microbiome, i.e. eubiosis, that is essential for healthy functioning of the young children bodies. In this specification, the following terms have the following meaning unless otherwise specified: "About" or "approximately" mean being close to the value or range following these terms, as understood by one of ordinary skill in the art and include a deviation up to 10 % of the values or ranges that follow. “Young child” in the present context means a young human of age up to about 3 years, such as an infant or a toddler. “Infant” means a young child of age up to 12 months old, i.e., from 1 day old to 365 days old. “Toddler” means is a young child of age between 12 to 36 months old. “Child nutritional formula” means a foodstuff which is suitable as a complete or partial substitute for human milk and is intended to satisfy the particular nutritional needs of infants during the first year of life, or young children of ages about 1 year to about 3 years. The child nutritional formula may be (i) a starter infant formula (also called an infant formula) which is suitable for infants from birth, (ii) a follow on formula which is suitable for infants over the age of six months, (iii) a food for special medical purposes / medical food which is intended for infants who have special dietary needs and who are unable to consume standard starter infant formulas and / or follow-on formulas, or (iv) a growing up milk which is suitable for supplementing the diet of young children of ages about 1 to about 3 years. Infant formulas and follow-on infant formulas are regulated in Europe under EU Regulation 2016 / 127. Food for special medical purposes for infants are regulated in Europe under EU Regulation 2016 / 128. Equivalent regulations exist in other geographies. "Comprising" means including the compound of interest and other related or non-related compounds. Related terms such as “contain”, “contained”, “containing”, "comprise" and "comprised" are to be interpreted in the same manner. “Dietary” means related to diet, i.e. routine consumption of nutrients for maintenance and growth of the body. “Dietary supplement” means a manufactured product intended to supplement a person's diet, in the present content, a young child diet. Typically, a dietary supplement has beneficial features, e.g. a biological activity, that may complement one or more normal dietary nutrient with its beneficial features or compensate for the lack or insufficient amount of one or more nutrients in the diet and thereby normalize the diet. According to the invention, synthetic compounds of formula (1) to (6), preferably of formula (1) are dietary supplements for young children. Beneficial features of the compounds preferably include, but not limited to supporting and / or promoting maturation of the immune system of young children; reducing colonization of the children gut by a pathogenic bacterial species and / or decreasing the risk of colonization by said bacterial species; maintaining and / or improving the child gut barrier integrity; and / or increasing in the children gut the quantities of nutrients essential for the children growth and maturation, such as vitamins, amino acids, etc. “Dietary treatment” means a therapeutic diet, i.e. a meal plan controls the intake of certain foods or nutrients. In the present content, “certain foods” means preferably infant formula, and “certain nutrients” means synthetic compounds of formula (1) to (6), preferably, of formula (1). According to the invention dietary treatment is not a substitute for a therapeutic treatment, wherein “therapeutic” means relating to the healing of a certain abnormal physiological condition or a disease, preferably, but not limited to, a pathologic (i.e. not normal / abnormal) physiological condition associated with infection of the gut with pathogenic microbial species, dysfunctional digestive system, allergy or other immunological disturbance, food intolerance, neurological, muscular or metabolic disfunction, even if all the mentioned conditions have been triggered by gut dysbiosis of the young child of concern. According to the invention, a dietary treatment with the compounds and compositions of the invention have a beneficial effect of recovery from dysbiosis, i.e. an imbalance in bacterial composition, changes in bacterial metabolic activities, or changes in bacterial distribution within the gut, to eubiosis, i.e. an interspecies balance of the gut microbiota community, and thereby they may have therapeutic -like effect on functioning of the gastrointestinal and / or immune systems, which both could be affected by dysbiosis and manifested by symptoms of abdominal pain or cramping, B12 and other vitamin / mineral deficiencies, bloating, constipation, diarrhea, fat malabsorption (losing weight despite proper nutrition), gas, gastroesophageal reflux disease (GERD), allergy, etc., however, it is not contemplated as a therapeutic treatment, but rather supplementary to such in a form of fortified diet. One embodiment of dietary treatment of the invention is a prophylactic treatment, wherein “prophylactic” means relating to preventing or reducing the likelihood of development of dysbiosis and diseases or conditions associated with thereof (like ones exemplified above and below) in a young child subject who does not have symptoms of these diseases or conditions. “Dysbiosis” means an imbalance in bacterial composition and / or total bacterial growth of the gut microbiome, changes in bacterial metabolic activities, or changes in bacterial distribution within the gut. Typically, the three types of dysbiosis are recognized: 1) Lack of / Loss of beneficial bacteria, 2) Overgrowth of potentially pathogenic bacteria, and 3) Loss of overall bacterial diversity. Dysbiosis early in life can influence the health of the infant acutely, as well as contribute to disease susceptibility later in life. Many diseases, such as IBD, Type 2 Diabetes, Crohn's, allergies, are suggested to be due, in part, to an alteration in the microbiome of the gut. Further, colonization of the gut by pathologic microorganisms, like Clostridium difficile, is also correlated with the gut dysbiosis. According to the invention, “dysbiosis” does not include a condition when certain beneficial bacteria of microbiome present in relative abundance compared to compared to other living organisms comprised in the microbiome. In the context of the invention, a relative abundance of bacterial species of phyla Actinobacteriota, Bacteroidota and / or Firmicutes in the gut microbiome of a young child is beneficial since it contributes to both diminishing existing dysbiosis and supporting normal functioning of gastrointestinal tract of the young child, and / or reducing the risk of development of gut dysbiosis in the young child later in life. "Effective amount" means an amount sufficient to render a desired treatment or management outcome in a human. An effective amount can be administered in one or more doses to achieve the desired treatment or management outcome. “Enteral administration” means any conventional form for delivery of a composition to a human that causes the deposition of the composition in the gastrointestinal tract (including the stomach). Methods of enteral administration include feeding through a naso-gastric tube or jejunum tube, oral, sublingual, and rectal. "Oral administration" means any conventional form for the delivery of a composition to a human through the mouth. Accordingly, oral administration is a form of enteral administration. The oral administration is a preferred embodiment of the invention. “Maturation” means a transition from pre-or underdeveloped stage to more developed stage. In some embodiments “maturation” could be used interchangeably with “development”. “Synthetic” means made by man. “Synthetic” is synonymous with “artificial“. In the context of the present invention “a synthetic compound” or “a synthetic composition” means that such compound or composition is produced chemically, biochemically and / or biotechnologically. In some embodiments, the synthetic composition may be produced as such via a chemical, biochemical and / or biotechnological process. In other embodiments the synthetic composition may be obtained by mixing isolated synthetic compounds produced via a chemical, biochemical and / or biotechnological process. According to the invention all compounds and composition described herein are synthetic. Non-limiting examples of synthetic compounds of the invention are ganglioside GM3 and GD3. “Ganglioside GM3” in the context of the invention means a synthetic compound of formula (1): (1), wherein R1is a C13-C17alkyl chain; R2is a C15-C19alkyl chain, preferably C18; and R3is a carbohydrate moiety Neu5Acα2-3-Galβ1-4-Glcβ1-. “Ganglioside GD3” in the context of the invention means a synthetic compound of formula (1): (1), wherein R1is a C13-C17 alkyl chain; R2is a C15- C19 alkyl chain, preferably C18; and R3is a carbohydrate moiety Neu5Acα2-8-Neu5Acα2-3-Galβ1-4-Glc β1-. “Nutritional” means providing a nutrient, i.e. a substance that provides nourishment essential for the maintenance of life and for growth. The term “a” grammatically is a singular, but it may as well mean the plural of e.g., the intended compound. For example, a skilled person would understand that in the expression “a glycosphingolipid”, the provision of not only one single glycosphingolipid, but of a variety of glycosphingolipids of the same type is meant. As used herein, the term “alkyl” refers to an acyclic straight or branched hydrocarbyl group having 1- 50 carbon atoms which may be saturated or contain one or more double and / or triple bonds (so, forming for example an alkenyl or an alkynyl), and / or which may be substituted or unsubstituted, as herein further described. Examples of “alkyl” include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, isobutyl, n-butyl, sec-butyl, tert-butyl, isopentyl, n-pentyl, neo-pentyl, n-hexyl, ethenyl, propenyl, 1-butenyl, 2-butenyl, isobutenyl,1-pentenyl, 2-pentenyl, 2-methyl-1-butenyl, 3-methyl-1- butenyl, 2-methyl-2-butenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, methylpentenyl, dimethylbutenyl, ethynyl, propynyl, 1-butynyl, 2-butynyl, pentynyl, and hexynyl, each of which may be substituted or unsubstituted. Typically, the term alkyl refers to a straight saturated acyclic hydrocarbyl group having 13-19 carbons, which may be substituted or unsubstituted, preferably unsubstituted. The skilled person would understand that when speaking of position C-1, C-2, C-3, C-4, C-5 etc., reference is herein always made to the respective carbon atoms of glycosphingolipid such as those represented by formula (1)-(6). The skilled person will understand that in formulas showing a specific compound, like for example formulas (1)-(6) unless the chemical formula expressly describes a carbon atom having a particular stereochemical configuration, the formula is intended to cover compounds where such a stereocenter has an R or an S configuration, or wherein a double bond has a cis or a trans configuration. The term “glycosyl moiety“ refers to a monosaccharide or an oligosaccharide (more than one monosaccharide units), wherein the anomeric carbon of the monosaccharide or the anomeric carbon at the reducing end of the oligosaccharide is engaged in a glycosidic bond with another chemical entity, such as a sphingolipid, and the bond, if not further specified, may be an alpha or a beta glycosidic bond. A glycosyl moiety having more than one monosaccharide unit may represent a linear or a branched structure. The monosaccharide unit is preferably any 5-9 carbon atom sugar, comprising aldoses (e.g. D-glucose, D-galactose, D-mannose, D-ribose, D-arabinose, L-arabinose, D-xylose, etc.), ketoses (e.g. D-fructose, D-sorbose, D-tagatose, etc.), deoxysugars (e.g. L-rhamnose, L-fucose, etc.), deoxy-aminosugars (e.g. N- acetylglucosamine, N-acetylmannosamine, N-acetylgalactosamine, etc.), uronic acids, ketoaldonic acids (e.g. sialic acid). The monosaccharide unit can form different cyclic structures such as pyranose (six-membered) cyclic structures or furanose (five-membered) cyclic structures. In some embodiments the glycosyl moiety derives from a monosaccharide, wherein the monosaccharide is a β-galactoside. In some embodiments, the glycosyl moiety derives from an oligosaccharide, wherein the oligosaccharide carries one or more terminal β-galactopyranosyl units. The glycosyl moieties according to the present invention may be illustrated in the following style: Galβ1-4Glc1-, wherein the dash (-) represents the point of attachment of the glycosyl moiety and wherein the glycosyl moiety, may be linked via an alpha or a beta glycosidic bond, preferably a beta glycosidic bond. In the context of the present invention, the term Glc is glucosyl moiety, the term Gal is a galactosyl moiety, and term Neu5Ac is a N-acetylneuraminosyl moiety. In one aspect, the present invention provides a composition comprising one or more synthetic compounds of formula (1), or salts thereof: wherein R1is a C13-C17 alkyl chain; R2is a C15-C19 alkyl chain, preferably C18; and R3is a glycosyl moiety selected from Neu5Acα2-3-Galβ1-4-Glcβ1-, or Neu5Acα2-8-Neu5Acα2-3- Galβ1-4-Glc β1-. In the context of the present invention, compounds of formula (1) may also be referred to as “glycosphingolipid”, wherein the term “glycosphingolipid” refers to a compound that structurally consists of a glycosyl moiety and a sphingolipid moiety. The glycosyl moiety is typically linked to the sphingolipid moiety via a glycosidic bond between the anomeric carbon at the reducing end of the glycosyl moiety and the hydroxyl group at the C-1 position of the sphingolipid. The sphingolipid moiety of the glycosphingolipid of the present invention typically derives from a ceramide. Ceramides denote in the context of the present invention naturally occurring ceramides, analogues thereof or derivatives thereof. Preferred ceramides are those naturally occurring in humans. Naturally occurring human ceramides [Cer] include, but are not limited to, Cer[NS], Cer[AS], Cer[EOS], Cer[NH], Cer[AH], or Cer[EOH], Cer[NP], Cer[AP], or Cer[EOP], Cer[NDS], Cer[ADS], or Cer[EODS]. The letters in brackets refer to the shorthand nomenclature developed by Motta et al. (1993) Biochim Biophys Acta. 1182:147-151 and expanded by Rabionet (2014) Biochim Biophys Acta.1841:422-434 and Masukawa et al., Journal of Lipid Research, 2008, 49, 1466-1476. Particularly, the letters N, A, and EO represent non-hydroxy fatty acids (N), alpha-hydroxy fatty acids (A), and omega-linoleoyloxy fatty acids (EO), respectively, wherein the number of fatty acid carbons and unsaturations may be expressed in parentheses following the letters of N, A, E, and O. The letters, S, H, P, and DS represent D-erythro- sphingosine (S), 6-hydroxy-D-erythro-sphingosine (H), D-ribo-phytosphingosine (P), D-erythro- dihydrosphingosine (DS), respectively, wherein the number of sphingoid carbons may be expressed in parenthesis following the letters S, H, P, and DS. Ceramides, Cer[NDS], Cer[ADS], or Cer[EODS], may also be referred to as Cer[NG], Cer[AG], or Cer[EOG], respectively, wherein the letter G represents the INCI name forD-erythro-dihydrosphingosine. Glycosphingolipids lacking the amide-linked fatty acyl group may also be referred to as lysosphingolipids. In some embodiments, said composition comprising one compound of formula (1). In some embodiments, the compound of formula (1) is a compound of formula (2), or a salt thereof: (2), wherein, R1and R2are defined as for the compound of formula (1). In some preferred embodiments, the compound of formula (1) is a compound of formula (2), wherein the compound of formula (2) is the ganglioside GM3. Accordingly in some preferred embodiments, the present invention provides a composition comprising the ganglioside GM3. In some embodiments, the compound of formula (1) is a compound of formula (3), or a salt thereof wherein R1and R2are as defined as for the glycosphingolipid of formula (1). In some preferred embodiments, the compound of formula (1) is a compound of formula (3), wherein the compound of formula (3) is the ganglioside GD3. Accordingly in some preferred embodiments, the present invention provides a composition comprising the ganglioside GD3. In some embodiments, the present invention provides a composition comprising more than one compound of formula (1). In some embodiments, the present invention provides a composition comprising a compound of formula (2) and a compound of formula (3), or salts thereof: (3), wherein R1and R2are as defined as for the glycosphingolipid of formula (1). In some preferred embodiments, the composition comprising a synthetic compound of formula (2) and a synthetic compound of formula (3), wherein the compound of formula (2) is the ganglioside GM3 and the compound of formula (3) is the ganglioside GD3. Preferably, the synthetic gangliosides GM3 and GD3 are structurally identical to GM3 and GD3 gangliosides (correspondingly) of human breast milk (termed herein “human identical”). Accordingly, in some preferred embodiments, the present invention provides a composition comprising synthetic human identical gangliosides GM3 and GD3. In some embodiments, the composition further comprising a synthetic compound of formula (4): wherein R1and R2are defined as for the compound of formula (1). In some embodiments, the compound of formula (4) is lactosylceramide [N(18) S(18)]. Lactosylceramide [N(18) S(18)] may also be referred to LacCer[N(18) S(18)]. Preferably, the synthetic lactosylceramide comprised in compositions of the invention is structurally identical to the lactosylceramide comprised in human breast milk. In some embodiments, the composition further comprising a synthetic compound of formula (5): wherein R1are R2are defined as for the compound of formula (1). In some embodiments, the compound of formula (5) is glucosylceramide [N(18) S(18)]. Glucosylceramide [N(18) S(18)] may also be referred to as GlcCer[N(18) S(18)]. Preferably, the synthetic glucosylceramide comprised in compositions of the invention is structurally identical to the glucosylceramide comprised in human breast milk. In some embodiments, the composition further comprising a synthetic compound of formula (6), or a salt thereof: (6), wherein R1and R2are defined as for the compound of formula (1). In some embodiments, the compound of formula (6) is a synthetic ganglioside GT3. Preferably, the synthetic ganglioside GT3 comprised in compositions of the invention is structurally identical to the ganglioside GT3 comprised in human breast milk. The synthetic human identical gangliosides GM3, GD3, GT3, lactosylceramide and glucosylceramide described above are further referred as GM3, GD3, GT3, lactosylceramide and glucosylceramide, correspondingly. In some preferred embodiments, R1of the compounds of formula (1)-(6) is an unsubstituted C13alkyl chain. In some embodiments, R2of the compounds of formula (1)-(6) is an unsubstituted C15-C19alkyl chain. In one embodiment, R2of the compounds of formula (1)-(6) is an unsubstituted C15 alkyl chain. In one preferred embodiment, R2of the compounds of formula (1)-(6) is an unsubstituted C17 alkyl chain. In one embodiment, R2of the compounds of formula (1)-(6) is an unsubstituted C19 alkyl chain. In some embodiments, R2of the compounds of formula (1)-(6) is a substituted C15-C19alkyl chain. In some embodiments, the composition of the present invention comprising more than one compound of formula (1)-(6) which differ from each other in the number of carbon atoms in the alkyl chain of R2. In one embodiment, said composition comprising a synthetic compound of formula (1) wherein R2is a C15 alkyl chain and a synthetic compound of formula (1) wherein R2is a C17 alkyl chain. Preferably the mass ratio of the compound of formula (1) wherein R2is a C15 alkyl chain and the compound of formula (1) wherein R2is a C17 alkyl chain is respectively from about 1:1 to about 1:4, for example from about 1:1.5 to about 1:3. In one embodiment, the mass ratio of the compound of formula (1) wherein R2is a C15alkyl chain and the compound of formula (1) wherein R2is a C17alkyl chain is respectively between about 1:1.5 to about 1:2.5. In one embodiment, said composition comprising a synthetic compound of formula (1) wherein R2is a C15 alkyl chain, a synthetic compound of formula (1) wherein R2is a C17 alkyl chain and a synthetic compound of formula (1) wherein R2is a C19 alkyl chain, and wherein the ratio between the compound of formula (1) wherein R2is a C15alkyl chain, the compound of formula (1) wherein R2is a C17alkyl chain, and the compounds of formula (1) wherein R2is a C19alkyl is respectively from about 1:1:1 to about 1:4:0.1, for example about 1:1.5:1 to about 1:3:0.1. If said composition comprises more than one compound of formula (1), R1 is preferably an unsubstituted C13 alkyl chain. In some embodiments, the composition of the present invention comprising a synthetic human identical ganglioside GM3. In some embodiments, the composition of the present invention comprising at least about 70 wt.% of GM3 of the invention, or at least about 75 wt.% of the GM3, or at least about 80 wt.% of the GM3, or at least about 85 wt.% of the GM3. In some embodiments, the composition of the present invention comprising the ganglioside GM3, and wherein said composition further comprising a synthetic human identical LacCer[N(18) S(18)] and synthetic human identical GlcCer[N(18) S(18)], respectively. In some embodiments, the composition of the present invention comprising about 70-85 wt.% of the GM3, and wherein said composition further comprising about 5-10 wt.% of the LacCer[N(18) S(18)] and about 0.5-1 wt.% of GlcCer[N(18) S(18)]. In some embodiments, the composition of the present invention comprising the ganglioside GM3 and the ganglioside GD3 respectively. In some embodiments, the composition of the present invention comprising the ganglioside GM3 and the ganglioside GD3, and wherein the mass ratio between GM3 and GD3 in said mixture is from about 0.2:14 to 14:0.2. For example, in some embodiments, the mass ratio between GM3 and GD3 in said composition may be about 14:1. In some other embodiments, the mass ratio between GM3 and GD3 in said composition may be about 0.2:1. In some other embodiments, the mass ratio between GM3 and GD3 in said composition may be about 5:1. In some embodiments, the composition of the present invention comprising the ganglioside GM3 and the ganglioside GD3, and wherein the mass ratio between GM3 and GD3 in said mixture is from about 1:10 to 10:1. For example, in some embodiments, the mass ratio between GM3 and GD3 in said composition may be about 10:1. In some other embodiments, the mass ratio between GM3 and GD3 in said composition may be about 3:1. In some other embodiments, the mass ratio between GM3 and GD3 in said composition may be about 1:1. In some embodiments, the mass ratio between GM3 and GD3 in said composition may be about 1:4. In some embodiments, the composition of the present invention comprising the ganglioside GM3 and the ganglioside GD3, and wherein said composition further comprising LacCer[N(18) S(18)] and GlcCer[N(18) S(18)]. In some embodiments, the composition of the present invention may comprise the ganglioside GM3 and the ganglioside GD3, and wherein said composition further comprising LacCer[N(18) S(18)], GlcCer[N(18) S(18)] and the ganglioside GT3. In some embodiments, the composition of the present invention comprises about 60-65 wt.% of the ganglioside GM3, about 20-25 wt.% of the ganglioside GD3, and wherein said composition further comprising about 5-10 wt.% LacCer[N(18) S(18)] and about 0.4-1 wt.% of GlcCer[N(18) S(18)]. In some embodiments, the composition of the present invention may comprise about 10-15 wt.% of the ganglioside GM3, about 40-55 wt.% of the ganglioside GD3, and wherein said composition further comprising about 4-6 wt.% of the ganglioside GT3, about 5-7 wt.% LacCer[N(18) S(18)] and about 0.4-1 wt.% of GlcCer[N(18) S(18)]. In some embodiments, the composition of the present invention may comprise up to about 95-98 wt.% gangliosides described therein and about 2-5 wt.% of LacCer[N(18) S(18)] and GlcCer[N(18) S(18)] together. The salt of the compound of formulas (1), (2), (3), and (6) can be any suitable salt which is compatible with food use. For example, a sodium, potassium, lithium, calcium, magnesium, zinc, aluminium, trietylamine, diethanolamine, ethanolamine, ethylenediamine, arginine, lysine, histidine, choline, benzathine, chloroprocaine, procaine, or meglumine salt. In one embodiment, the composition of the present invention can be obtained by a method comprising the steps of: ─ Reacting 3’-sialyllactose, an enzyme having trans-sialidase activity, an enzyme having β- galactosidase activity, and a compound formula (7), or a salt thereof: (7), wherein R1is as defined as for the compound of formula (1); to obtain a composition comprising a compound of formula (8), or a salt thereof: wherein R1is as defined as for the compound of formula (1); ─ Reacting the composition comprising the compound of formula (8) with one or more triazine triazine-based acylating agents of formula (9): (9), wherein represents a conjugated system of bonds such that either two or three double bonds are present in the ring, Y is selected from C(O-C(=O)R2), or C(=O), Xais selected from N, NR4, or N(C(=O)R2) Xbis selected from N, or NR4Z is selected from C(=O), or C(OR4), and provided that: when Y is C(O-C(=O)R2), Z is C(OR4), Xaand Xbare N, and three double bonds are present in the ring, or when Y is C(O-C(=O)R2), Z is C(=O), one of Xaand Xbis N and the other group is NR4, and two double bonds are present in the ring, or when Y is C(=O), Z is C(OR4), Xais N(C(=O)R2), Xbis N, and two double bonds are present in the ring, and wherein R2is as defined as for the compound of formula (1), R4is selected from methyl, ethyl, 2,2,2-trifluoroethyl, and substituted or unsubstituted benzyl; to produce the composition comprising the compound of formula (2). In another embodiment, the composition of the present invention can be obtained by a method comprising the steps of: ─ Reacting 3’-sialyllactose, an enzyme having trans-sialidase activity, an enzyme having β- galactosidase activity, and a compound formula (7), or a salt thereof: wherein R1is as defined as for the compound of formula (1); to obtain a composition comprising a compound of formula (8), or a salt thereof: (8), wherein R1is as defined as for the compound of formula (1); ─ Reacting the composition comprising the compound of formula (8) with a mixture comprising sialic acid, cytidine monophosphate (CMP), a nucleoside triphosphate, and at least five enzymes, in which the at least five enzymes comprise at least one enzyme having sialyltransferase activity, at least one enzyme having a N-acylneuraminate citydyltransferase activity, at least one enzyme having inorganic diphosphatase activity, and at least two enzymes having kinase activity; to obtain a composition comprising a compound of formula (10), or a salt thereof: (10), wherein R1is as defined as for the compound of formula (1); ─ Reacting the composition comprising the compound of formula (10) with one or more triazine triazine-based acylating agents of formula (9): represents a conjugated system of bonds such that either two or three double bonds are present in the ring, Y is selected from C(O-C(=O)R2), or C(=O), Xais selected from N, NR4, or N(C(=O)R2) Xbis selected from N, or NR4Z is selected from C(=O), or C(OR4), and provided that: when Y is C(O-C(=O)R2), Z is C(OR4), Xaand Xbare N, and three double bonds are present in the ring, or when Y is C(O-C(=O)R2), Z is C(=O), one of Xaand Xbis N and the other group is NR4, and two double bonds are present in the ring, or when Y is C(=O), Z is C(OR4), Xais N(C(=O)R2), Xbis N, and two double bonds are present in the ring, and wherein R2is as defined as for the compound of formula (1), R4is selected from methyl, ethyl, 2,2,2-trifluoroethyl, and substituted or unsubstituted benzyl; to produce the composition comprising the compound of formula (3), or the composition comprising the compounds of formula (2) and of formula (3). “Enzyme having a β-galactosidase activity” means an enzyme belonging to the glycoside hydrolase family 35 (GH35) which typically catalyses the hydrolysis of terminal non-reducing β-d-galactose residues in β-d-galactosides. An enzyme having a β-galactosidase activity is used interchangeably with the term “β-galactosidase”. A β-galactosidase may also be referred to as lactase. “Enzyme having a trans-sialidase activity” means an enzyme belonging to the glycoside hydrolase family 33 (GH33) which typically catalyzes the reversible transfer of a glycosidically linked sialic acid from sialic acid donors such as oligosaccharides, glycoproteins, glycolipids, and colominic acid to acceptor molecules containing a terminal β-galactopyranosyl unit. Enzyme having a trans-sialidase activity is used interchangeably with the term “trans-sialidase”. In the absence of a suitable acceptor molecule, an enzyme having a trans-sialidase activity may act as a sialidase and transfer a glycosidically linked sialic acid to a water molecule. However, the hydrolytic activity is typically low. “Enzyme having inorganic diphosphatase activity” means an enzyme that catalyzes the hydrolysis of pyrophosphate (PPi). An enzyme having inorganic diphosphatase activity is used interchangeably with the term “inorganic diphosphatase” or “PPase”. “Enzyme having N-acylneuraminate cytidyltransferase activity” means an enzyme that catalyzes the transfer of CMP from CTP to N-acetyl-neuraminic acid (Neu5Ac). An enzyme having N- acylneuraminate cytidyltransferase activity is used interchangeably with the term “N-acylneuraminate cytidylyltransferase” or “CSS”. “Enzyme having a nucleoside diphosphate kinase activity” means an enzyme that catalyzes the phosphorylation of a nucleoside diphosphate. An enzyme having a nucleoside diphosphate kinase activity is used interchangeably with the term “nucleoside-diphosphate kinase” or “NDK”. “Enzyme having a sialyltransferase activity” means an enzyme belonging to the glycosyltransferase family 29 (GT29), or to the glycosyltransferase family 42 (GT42) which typically catalyzes the transfer of sialic acid from CMP-sialic acid to a saccharide acceptor. Enzyme having a sialyltransferase activity is used interchangeably with the term “sialyltransferase” and The enzyme having trans-sialidase activity in its wild-type form, may originate from parasitic euglenoids, such as Trypanosoma cruzi, Trypanosoma congolense, or Trypanosome brucei. In some embodiments, the enzyme having trans-sialidase activity is a wild-type trans-sialidase originating from Trypanosoma cruzi. The amino acid sequence of the wild-type trans-sialidase originating from Trypanosoma cruzi can be found on https: / / www.uniprot.org / , accession: Q26966. The trans-sialidase originating from Trypanosoma cruzi may also be referred to as TcTS. In some embodiments, the enzyme having trans-sialidase activity is a mutant of the wild-type trans- sialidase originating from Trypanosoma cruzi (Q26966). In some embodiments, the mutant trans- sialidase has at least five mutations at amino acid positions selected from the following positions (numbered corresponding to alignment of the amino acid sequence with the amino acid sequence of Q26966): S263T, R477H, V485L, E559V, N59F, S496K, V497G, E521K, D594G, I598D and H600R. In some embodiments, the amino acids sequence of the mutant trans-sialidase is that described on https: / / www.rcsb.org / structure / 1MS0. The mutant trans-sialidase may be produced by methods known to the skilled person. A method for the expression and purification of a mutant trans-sialidase is for example described in Paris et al., Glycobiology 2001, 11, 305-311, or in Buschiazzo et al., Molecular Cell 2002, 10, 757-768. The enzyme having β-galactosidase activity in its wild-type form, may originate from Aspergillus oryzae. In some preferred embodiments, the enzyme having β-galactosidase activity is a truncated variant of the wild-type β-galactosidase originating from Aspergillus orizyae (Q2UCU3). The truncated variant of the β-galactosidase can be purchased from established manufacturers, e.g. Calza Clemente, or produced by methods known to the skilled person such as that described in M.M. Maksimainen et al., International Journal of Biological Macromolecules 2013, 60, 109–115. In some embodiments, the enzyme having sialyltransferase activity is a wild-type α-2,3 / α-2,8- sialyltransferase originating from Campylobacter jejuni, strain OX=197, or a functional analogue thereof. The amino acid sequence of the wild-type α-2,3 / α-2,8-sialyltransferase originating from Campylobacter jejuni, strain OX=197 can be found on https: / / www.uniprot.org / , accession: Q9LAK3. The α-2,3 / α-2,8-sialyltransferase originating from Campylobacter jejuni is referred to as CST-II. In some embodiments, the enzyme having sialyltransferase activity is a mutant of the wild-type α- 2,3 / α-2,8-sialyltransferase originating from Campylobacter jejuni, strain OX=197 (Q9LAK3). In some embodiments, the mutant α-2,3 / α-2,8-sialyltransferase has a mutation at the amino acid 15 position I53G (numbering corresponding to alignment of the amino acid sequence with the amino acid sequence of Q9LAK3), as described in Gilbert et al., Biological Chemistry 2002, 277, 327–337. In some embodiments, the triazine-based acylating agents of formula (9) is a triazine-based acylating agent selected from triazine based acylating agents of formulas (11) and (12):

[0002] wherein R2is as defined as the compound of formula (1), and R4is as defined as for the triazine-base acylating agent of formula (9). In some embodiments, triazine triazine-based acylating agents of formula (9) is a triazine-based acylating agent selected from triazine based acylating agents of formulas (13) and (14): wherein R2is as defined as the compound of formula (1), and R4is as defined as for the triazine-base acylating agent of formula (9). The compound of formula (7) and the triazine base-acylating agents of formulas (9) and (11)-(14) can be obtained by method known to the skilled person. For instance, a method to produce a compound of formula (7) is described by Vaughan et al., J. Am. Chem. Soc. 2006, 128, 6300-6301. A method to produce a triazine-based acylating of formula (9) and (11)-(14) is for example described by Kaminski et al., Journal f. prakt. Chemie.1990, Band 332, Heft 4, S.579-383. A detailed description of the method of producing the composition according to the present invention can be found in the examples below. In some preferred embodiments, the nucleoside triphosphate is adenosine 5'-triphosphate (ATP), and the at least five enzymes comprise the following enzyme: ─ an enzyme having sialyltransferase activity, ─ an enzyme having cytidine monophosphate kinase activity, ─ an enzyme having nucleoside diphosphate kinase activity, ─ an enzyme having N-acylneuraminate cytidyltransferase activity, and ─ an enzyme having inorganic diphosphatase activity. In some preferred embodiments, the enzyme having cytidine monophosphate kinase activity is a wild- type CMP kinase originating from Mycobacterium tuberculosis, or a functional analogue thereof. The amino acid sequence of the wild-type CMP kinase originating from Mycobacterium tuberculosis can be found on https: / / www.ncbi.nlm.nih.gov / genbank / , accession: WP_129368399. The CMP kinase originating from Mycobacterium tuberculosis is also referred to as MtCMK. In some embodiments, the enzyme having nucleoside diphosphate kinase activity is a wild-type nucleoside-diphosphate kinase originating from Mycobacterium tuberculosis complex, or a functional analogue thereof. The amino acid sequence of the wild-type nucleoside-diphosphate kinase originating from Mycobacterium tuberculosis complex, can be found on https: / / www.ncbi.nlm.nih.gov / genbank / , accession: WP_003412592. The nucleoside-diphosphate kinase originating from Mycobacterium tuberculosis complex may also be referred to as MtNDK. In some preferred embodiments, the enzyme having N-acylneuraminate cytidyltransferase activity is a wild-type N-acylneuraminate cytidylyltransferase originating from Neisseria meningitidis or a functional analogue thereof. The amino acid sequence of the wild-type N-acylneuraminate cytidylyltransferase originating from Neisseria meningitidis can be found on https: / / www.ncbi.nlm.nih.gov / genbank / , accession: WP_061726245. The N-acylneuraminate cytidyltransferase originating from Neisseria meningitidis is also referred to as NmCSS. In some embodiments, the enzyme having inorganic diphosphatase activity is a wild-type inorganic diphosphatase originating from Escherichia coli, or a functional analogue thereof. The amino acid sequence of the wild-type inorganic diphosphatase originating from Escherichia coli can 30 be found on https: / / www.ncbi.nlm.nih.gov / genbank / , accession: WP_073849715. The inorganic diphosphatase originating from Escherichia coli is also referred to as EcPPase. The mutated variant and the wild-type enzymes used during the sialyltransferase cycle, can be purchased from established manufacturers, or produced by methods known to the skilled person. For instance, the mutant of the wild-type α-2,3 / α-2,8-sialyltransferase originating from Campylobacter jejuni can be produced by the method described in Gilbert et al., Biological Chemistry 152002, 277, 327–337, whereas the wild-type enzymes can be produced by the method described elsewhere in molecular cloning textbooks. In another aspect, the invention provides a child nutritional formula which comprises the composition as defined above. The composition, as defined above comprising one or more compounds of formula (1), and in some embodiment further comprising a compound of formula (4), (5), and / or (6). In some embodiments, the child nutritional formula comprising the composition according to the present invention, wherein said composition comprising gangliosides GM3 and GD3, wherein the total content of gangliosides GM3 and GD3 in said child nutritional formula is between about 5 mg / l and about 35mg / l, preferably between about 6 mg / l and about 26 mg / l, and wherein the ratio between gangliosides GM3 and GD3 is from about 0.2:1 to about 14:1, preferably from about 0.2:1 to 5:1. In some embodiments, the child nutritional formula comprising the composition according to the present invention, wherein said composition comprising ganglioside GM3, and wherein the total content of GM3 in said child nutritional formula is between about 5 mg / l and about 35mg / l, preferably between about 6 mg / l and about 26 mg / l. In some embodiments, the child nutritional formula comprising the composition according to the present invention, wherein said composition comprising gangliosides GM3 and GD3, and wherein said composition further comprising LacCer[N(18) S(18)], GlcCer[N(18) S(18)] and ganglioside GT3. In some embodiments, the child nutritional formula comprising the composition according to the present invention, wherein said composition comprising gangliosides GM3, and wherein said composition further comprising LacCer[N(18) S(18)] and GlcCer[N(18) S(18)]. In one embodiment, the child nutritional formula comprises from about 0.001 mg / kcal to about 0.04 mg / kcal of one or more compounds compound of formula (2). For example, the child nutritional formula may comprise from about 0.003 mg / kcal to about 0.025 mg / kcal of the one or more compounds of formula (2), or about 0.004 mg / kcal to about 0.017 mg / kcal of the one or more compounds of formula (2). When in a ready to feed form, the child nutritional formula can contain from about 1 mg / l to about 20 mg / l of the one or more compounds of formula (2), for example about 2 mg / l to about 15 mg / l, or about 3 mg to about 10 mg / l. In one embodiment, the child nutritional formula comprises from about 0.0001 mg / kcal to about 0.017 mg / kcal of the compound of formula (3). For example, the child nutritional formula may comprise from about 0.0003 mg / kcal to about 0.008 mg / kcal of the compound of formula (3), or from about 0.004 mg / kcal to about 0.003 mg / kcal of the compound of formula (3). When in a ready to feed form, the child nutritional formula can contain from about 0.1 mg / l to about 10 mg / l of the compound of formula (3), for example from about 0.2 mg / l to about 5 mg / l, or from about 0.3 mg to about 2 mg / l. In one embodiment, the child nutritional formula comprises about 0.0001 mg / kcal to about 0.025 mg / kcal of the compound of formula (4). For example, the child nutritional formula may comprise from about 0.0003 mg / kcal to about 0.017 mg / kcal of the compound of formula (4), or from about 0.004 mg / kcal to about 0.008 mg / kcal of the compound of formula (4). When in ready to feed form, the child nutritional formula can contain from about 0.1 mg / l to about 15 mg / l of the compound of formula (4), for example from about 0.2 mg / l to about 10 mg / l, or from about 0.3 mg to about 5 mg / l. In one embodiment, the child nutritional formula comprises from about 0.0001 mg / kcal to about 0.025 mg / kcal of the compound of formula (5). For example, the child nutritional formula may comprise about 0.0003 mg / kcal to about 0.017 mg / kcal of the compound of formula (5), or about 0.004 mg / kcal to about 0.008 mg / kcal of the compound of formula (5). When in ready to feed form, the child nutritional formula can contain about 0.1 mg / l to about 15 mg / l of the compound of formula (5), for example from about 0.2 mg / l to about 10 mg / l, or from about 0.3 mg to about 5 mg / l. The child nutritional formula as any of described above can comprise a source of protein. The source of protein can be in the form of intact protein, partially hydrolyzed protein, extensively hydrolyzed protein, or amino acids. The protein source can be any source of protein which is suitable for infants, for example cow’s milk protein, goat’s milk protein, rice protein, pea protein, soya protein, and the like. The milk protein may be in the form of whey protein, casein, or combinations of whey and casein. The protein source can be supplemented with free amino acids such that it provides enough of each indispensable and conditionally indispensable amino acid in human breast milk. The protein content of the child nutritional formula is preferably in the range of about 1.8 g / 100 kcal to about 3.2 g / 100 kcal (about 0.43 g to about 0.76 g carbohydrate per 100 KJ). If the protein source is an intact milk protein, the protein content is preferably in the range of about 1.8 g / 100 kcal to about 2.5 g / 100 kcal (about 0.43 g to about 0.6 g carbohydrate per 100 KJ). If the protein source is or includes a plant protein (e.g., rice, soya and the like), the protein content is preferably in the range of about 2.25 g / 100 kcal to about 2.8 g / 100 kcal (about 0.54 g to about 0.67 g carbohydrate per 100 KJ). If the protein source is a hydrolyzed protein, the protein content is preferably in the range of about 1.8 g / 100 kcal to about 2.8 g / 100 kcal (about 0.43 g to about 0.67 g carbohydrate per 100 KJ). If the protein source is free amino acids, the protein content is preferably in the range of about 2.8 g / 100kcal to 3.1 g / 100 kcal. For certain infants, such as those suffering gastrointestinal pathologies with severe malabsorption or premature infants, the protein content can be higher, for example up to 4.1 g / 100 kcal (0.97 g / 100 KJ). The child nutritional formula as any of described above can also comprise a digestible carbohydrate. Examples of digestible carbohydrates include lactose, maltose, sucrose, glucose, glucose syrup or dried glucose syrup, maltodextrins, and starch. Mixtures of carbohydrates can also be used. If the child nutritional formula is intended for preterm infants, the carbohydrate source preferably contains less or no lactose. The digestible carbohydrate content of the child nutritional formula is preferably in the range of from about 9 g / 100 kcal to about 14 g / 100 kcal (from about 2.2 g to about 3.3 g carbohydrate per 100 KJ). The child nutritional formula as any of the described above can further comprise a source of lipid. The lipid source may be any lipid which is suitable for use in infant nutrition. Preferred lipid sources include milk fat, sunflower oil, rapeseed oil, safflower oil, egg yolk lipid, olive oil, coconut oil, palm oil, palm kernel oil, soybean oil, fish oil, and microbial fermentation oil containing. These oils may be in the form of high oleic forms such as high oleic sunflower oil and high oleic safflower oil. The lipid source may also be in the form of fractions derived from these oils such as palm olein, medium chain triglycerides (MCT), and esters of fatty acids such as linoleic acid, palmitic acid, stearic acid, linolenic acid, oleic acid, lauric acid, capric acid, caprylic acid, caproic acid, and the like. The lipid source can also include structured lipids (i.e., lipids that are modified chemically or enzymatically to change their structure). Preferably, the structured lipids are sn2 structured lipids, for example comprising triglycerides having an elevated level of palmitic acid at the sn2 position of the triglyceride. The lipid source can also include oils containing high concentrations of long-chain, polyunsaturated fatty acids such as arachidonic acid (ARA), docosahexaenoic acid (DHA), and / or eicosapentaenoic acid such as fish oils or microbial oils. If the Child nutritional formula is intended for preterm infants, the lipid source preferably contains MCT. For example, the lipid source can contain up to 40% by weight of MCT, preferably about 15% to about 35% by weight of the lipid source. The lipid content of the child nutritional formula is preferably in the range of from about 4.4 g / 100 kcal to about 6 g / 100 kcal (from about 1.1 g to about 1.4 g lipid per 100 KJ). If the child nutritional formula contains ARA, the amount of ARA is preferably in the range of from about 2mg to about 20 mg ARA per 100 kcal, for example about 5mg to about 15mg ARA per 100 kcal. If the child nutritional formula contains DHA, the amount of DRA is preferably in the range of about 2mg to about 20 mg DHA per 100 kcal, for example about 5mg to about 15 DHA per 100 kcal. For example, the child nutritional formula can contain about 10 mg ARA per 100 kcal and about 10 mg DHA per 100 kcal. The mass ratio of n-6 to n-3 fatty acids can be from about 5: 1 to about 15: 1; for example, about 8: 1 to about 10: 1. When in nutritionally complete form, the child nutritional formula contains all vitamins and minerals understood to be essential in the daily diet and in nutritionally adequate amounts. Minimum requirements have been established for certain vitamins and minerals. Minerals which are normally required include sodium, potassium, chloride, calcium, phosphorous, magnesium, iron, zinc, copper, iodine, selenium, manganese, molybdenum, and fluoride. In general, the molar ratio of calcium to available phosphorus is about 1:1 to about 2:1. Vitamins which are normally required include vitamin A, vitamin D, thiamine (vitamin Bl), riboflavin (vitamin B2), niacin (vitamin B3), pantothenic acid (vitamin B5), vitamin B6, biotin (vitamin B7), folate (vitamin B9), vitamin Bl2, vitamin C, vitamin E, and vitamin K. The child nutritional formula may further contain one or more carotenoids. The child nutritional formula can contain a source of other essential nutrients such as choline. Suitable sources of choline include milk fat, milk fat fractions, phospholipids, and choline salts. In general, the child nutritional formula can contain about 7 mg / 100 kcal to about 50 mg / 100 kcal. The child nutritional formula can also contain a source inositol. For example, the child nutritional formula may contain about 4 mg / 100 kcal to about 150 mg / 100 kcal. The child nutritional formula can also comprise at least one probiotic. If the probiotic is capable of producing lactic acid, a probiotic which produce L(+) lactic acid is preferred. Examples of probiotics include yeasts, such as Saccharomyces; and bacteria, such as the genera Bifidobacterium, Bacteroides, Clostridium, Fusobacterium, Melissococcus, Propionibacterium, Streptococcus, Lactococcus, Staphylococcus, Peptostrepococcus, Bacillus, Pediococcus, Micrococcus, Leuconostoc, Weissella, Aerococcus, Oenococcus and Lactobacillus. Specific examples of suitable probiotics are: Saccharomyces cereviseae, Bacillus coagulans, Bacillus licheniformis, Bacillus subtilis, Bifidobacterium bifidum, Bifidobacterium infantis, Bifidobacterium longum, Bifidobacterium breve, Enterococcus faecium, Enterococcus faecalis, Lactobacillus acidophilus, Lactobacillus alimentarius, Lactobacillus casei subsp. casei, Lactobacillus casei Shirota, Lactobacillus curvatus, Lactobacillus delbruckii subsp. lactis, Lactobacillus farciminus, Lactobacillus gasseri, Lactobacillus helveticus, Lactobacillus johnsonii, Lactobacillus rhamnosus ( Lactobacillus GG), Lactobacillus sake, Lactococcus lactis, Lactobacillus reuterii, Micrococcus varians, Pediococcus acidilactici, Pediococcus pentosaceus, Pediococcus acidilactici, Pediococcus halophilus, Streptococcus faecalis, Streptococcus thermophilus, Staphylococcus carnosus and Staphylococcus xylosus. The child nutritional formula can also comprise a source of non-digestible carbohydrates. Suitable non- digestible carbohydrates include human milk oligosaccharides, galacto-oligosaccharides, fructo- oligosaccharide, polydextrose, and mixtures of these oligosaccharides. Preferably the child nutritional formula contains a source of human milk oligosaccharides, for example 2’-fucosyllactose, 3- fucosyllactose, di-fucosyllactose, lacto-N-fucopentaose 1, lacto-N-tetraose, lacto-N-neotetraose, 3’- sialyllactose, 6’-sialyllactose, disialyllacto-N-tetraose, and mixtures of these oligosaccharides. The child nutritional formula may comprise from about 0.02 g / 100kcal to about 3 g / 100kcal of non- digestible carbohydrates, for example from about 0.02 g / 100kcal to about 2.25 g / 100kcal. In one embodiment, the source of non-digestible carbohydrates includes an acidic human milk oligosaccharide such as 3’-sialyllactose, 6’-sialyllactose, and / or disialyllacto-N-tetraose. The acidic human milk oligosaccharide can be present in an amount from 0.015 g / 100kcal to about 0.23 g / 100 kcal, for example from about 0.02 g / 100 kcal to about 0.15 g / 100 kcal. This corresponds to the amount from about 0.1 g / l to about 1.5 g / l, for example about 0.13 g / l to about 1 g / l, in ready to feed liquid. In another embodiment, the source of non-digestible carbohydrates includes a fucosyl human milk oligosaccharide such as 2’-fucosyllactose, 3-fucosyllactose, di-fucosyllactose, lacto-N-fucopentaose 1. The acidic human milk oligosaccharide can be present in an amount from about 0.015 g / 100kcal to about 1.5 g / 100 kcal, for example from about 0.02 g / 100 kcal to about 1.0 g / 100 kcal. This corresponds to the amount from about 0.1 g / l to about 10 g / l, for example from about 0.13 g / l to about 6.7 g / l, in ready to feed liquid. In another embodiment, the source of non-digestible carbohydrates includes a core human milk oligosaccharide such as lacto-N-tetraose and / or lacto-N-neotetraose. The core human milk oligosaccharide can be present in an amount from 0.015 g / 100kcal to about 0.3 g / 100 kcal, for example from about 0.02 g / 100 kcal to about 0.23 g / 100 kcal. This corresponds to the amount from about 0.1 g / l to about 2 g / l, for example from about 0.13 g / l to about 1.5 g / l, in ready to feed liquid. The child nutritional formula can also comprise a source of animal milk fat globule membrane, especially cow milk fat globule membrane. The source of animal milk fat globule membrane can be selected from whole animal milk or a concentrated fraction of animal. Suitable concentrated fractions of animal milk include buttermilk, beta serum and fat-fractions obtained during the production of whey protein concentrates or whey protein isolates. Sources of milk fat globule membrane in the form of concentrated fractions of animal milk are commercially available. The child nutritional formula can comprise other substances which may be beneficial to the infants and toddlers such as lactoferrin, nucleotides, nucleosides, sphingomyelin, and the like. If desired, the child nutritional formula can comprise emulsifiers and stabilizers such as soy lecithin, citric acid esters of mono-and di-glycerides, and the like. This is especially the case if the child nutritional formula is provided in liquid form. The child nutritional formula can be prepared in any suitable manner. For example, a child nutritional formula can be prepared by blending the protein source, the carbohydrate source, and the lipid source in appropriate proportions. If used, emulsifiers may be included in the blend. The vitamins and minerals may be added at this stage but are usually added later to avoid thermal degradation. Any lipophilic vitamins, emulsifiers and the like may be dissolved into the lipid source prior to blending. The ganglioside composition can be included in the lipid source prior to blending. Water, preferably water which has been subjected to reverse osmosis, may then be mixed in to form a liquid mixture. The liquid mixture then can be thermally treated to reduce bacterial loads. For example, the liquid mixture may be rapidly heated to a temperature in the range of about 80°C to about 110°C for about 5 seconds to about 5 minutes. This may be carried out by steam injection or by heat exchanger, for example a plate heat exchanger. The liquid mixture then can be cooled to about 60°C to about 85°C, for example by flash cooling. The liquid mixture then can be homogenized, for example in two stages at about 7 MPa to about 40 MPa in the first stage and about 2 MPa to about 14 MPa in the second stage. The homogenized mixture then can be further cooled to add any heat sensitive components, such as vitamins and minerals. The pH and solids content of the homogenized mixture is conveniently standardized at this point. If it is desired to produce a powdered child nutritional formula, the homogenized mixture is transferred to a suitable drying apparatus such as a spray drier or freeze drier and converted to powder. The powder preferably has a moisture content of less than about 5% by weight. If it is desired to produce a liquid child nutritional formula, the homogenized mixture is filled into suitable containers, preferably aseptically. However, the liquid child nutritional formula also can be retorted in the container. Suitable apparatus for carrying out filling of this nature is commercially available. The liquid child nutritional formula may be in the form of a ready to feed formula having a solids content of about 10 to about 14% by weight or may be in the form of a concentrate, usually having a solids content of about 20 to about 26% by weight. The presence of synthetic compounds and compositions of the invention in a child nutritional formula have multiple benefits for young children, as the compounds and compositions comprising thereof stimulates colonization of beneficial bacterial species of phyla Actinobacteriota, Bacteroidota and / or Firmicutes that contribute to eubiosis, i.e., a healthy and balanced composition of microbiota that contributes to the metabolic function, protection against pathogens and provides nutrients and energy to the host. Any young child would benefit from a dietary supplement comprising the synthetic compounds of the invention. For example, in children with no current gastrointestinal problems the compounds would sustain eubiosis and contribute to healthy growth and development of the children, and also reduce the risk of development of dysbiosis, i.e. an imbalance in the diversity of microorganisms that greatly influences the state of health and disease, in their gut. Children with symptoms of disbalanced microbiome, i.e. who has or on the way to develop dysbiosis, would be relieved from these symptoms as the compounds would restore eubiosis and sustain it. The compounds and compositions of the invention stimulate the growth and physiological activity of beneficial bacteria of microbiota of the young child gut and thereby promote healthy functionality and maturation of the young child digestive and immune systems and the young child growth and development. According to the invention the compounds and composition comprising thereof surprisingly increase the relative abundance of one or more of following bacterial species in the young child gut microbiota: Bifidobacterium longum, Bifidobacterium breve, Bifidobacterium scardovii, Bacteroides caccae, Bacteroides uniformis, Bacteroides stercoris, Bacteroides xylanisolvens, Parabacteroides merdae, Faecalibacterium prausnitzii, Collinsella aerofaciens, Ruthenibacterium lactatiformans, Ruminococcus gnavus, Hungatella hathewayi. These microbiota species provide minerals and synthesize biologically active molecular, e.g. vitamins, metabolites, e.g. SCFAs, that are essential nutrients for the child growth, development and maturation and contribute to a healthy functioning of gastrointestinal tract of young children, reduce the risk of development of inflammatory conditions in the children gut, These bacteria also reduce the risk of pathogenic microorganism infection. Accordingly, embodiments of the invention include use of the compounds and compositions as a dietary supplement for young children, wherein that dietary supplement - supports and / or promotes maturation of the immune system of the child; and / or - reduces the risk of colonization of the child gut by a pathogenic bacterial species and / or decreases the risk of colonization thereof; and / or - maintains and / or improves the child gut barrier integrity; and / or - provides to the child gut the nutrients essential for the child growth, development and maturation, such as vitamins, amino acids, short-chain fatty acids, and thereby it reduces the likelihood of development of a metabolic disease or condition, like diabetes, cardio-vascular disease or obesity, inflammatory disease, like IBD or Cohn’s disease, allergic disease or condition, like asthma, and / or food intolerance in the child in the time of treatment and later in life. According to the invention any young child would benefit from oral intake of a dietary supplement comprising one or more compounds of the invention, however, the invention contemplates that the youngest children might benefit the most. Accordingly, in some preferred embodiments of the invention, the young child is an infant of 1 day to 365 days old. The amount of the compounds or composition required to be administered will vary depending upon factors such as the age of a child or child’s gastrointestinal status, or other factor like underlying medical conditions or socio-environmental factors, like family conditions. However, the required amount can be readily set by a medical practitioner and would generally be in the range from about 1 mg to about 30 mg per day, in certain embodiments from about 2 mg to about 20 mg per day, for example from about 3 mg to about 10 mg per day. An appropriate dose can be determined based on several factors, including, for example, body weight and / or condition, the severity of the inflammation, other ailments and / or diseases, the incidence and / or severity of side effects and the manner of administration. Appropriate dose ranges may be determined by methods known to those skilled in the art. The duration of the administration of the compounds or compositions will also vary depending upon the factors as those mentioned above. However, the duration can be readily set by a medical practitioner. For example, the composition can be administered during the first week of life of the child, or during the first 2 weeks of life, or during the first 3 weeks of life, or during the first month of life, or during the first 2 months of life, or during the first 3 months of life, or during the first 4 months of life, or during the first 6 months of life, or during the first 8 months of life, or during the first 10 months of life, or during the first year of life, or during the first three years of life. The compounds or composition can be administered daily, or with intervals between administration longer than a day. Further, the composition can be administered more than once a day. Selected preferred embodiments of the invention 1. A synthetic compound of formula (1), or salt thereof: wherein R1is a C13-C17alkyl chain; R2is a C15-C19alkyl chain, preferably C18; and R3is a carbohydrate moiety selected from: Neu5Acα2-3-Galβ1-4-Glcβ1-, or Neu5Acα2-8-Neu5Acα2-3-Galβ1-4-Glc β1-; for use in dietary treatment or prophylaxis of gut dysbiosis in a young child. . The synthetic compound for use according to embodiment 1, wherein the compound enhances the relative abundance of bacterial species of phyla Actinobacteriota, Bacteroidota and / or Firmicutes in the gut microbiome of the young child when an effective amount of the compound is administered to said child orally in one or more doses per day during at least 7 days. . A nutritional composition comprising one or more synthetic compounds for use according to embodiment 1 or 2. . The nutritional composition for use according to embodiment 3, comprising a synthetic compound of formula (2), or a salt thereof: wherein, R1and R2are defined as for the compound of formula (1). . The nutritional composition for use according to embodiment 3, comprising a synthetic compound of formula (3), or a salt thereof: wherein R1and R2are as defined as for the glycosphingolipid of formula (1) . The nutritional composition for use according to embodiment 3, comprising a synthetic compound of formula (2) and of formula (3), or salts thereof: wherein R1and R2are as defined as for the glycosphingolipid of formula (1). The nutritional composition for use according to embodiment 6, wherein the ratio between the synthetic compound of formula (2) and the synthetic compound of formula (3) is from about 0.2:1 to about 14:1, preferably from about 0.2:1 to 5:1. The nutritional composition for use according to any one of embodiments 3 to 7, further comprising a synthetic compound of formula (4): wherein R1and R2are defined as for the compound of formula (1). The nutritional composition for use according to any one of embodiments 3 to 8, further comprising a synthetic compound of formula (5): (5) wherein R1and R2are defined as for the compound of formula (1). 10. The nutritional composition for use according to any one of embodiments 3 to 9, further comprising a synthetic compound of formula (6): wherein R1and R2, Glc, Gal, and Neu5Ac are defined as for the compound of formula (1). 11. The nutritional composition for use of any one of embodiments 3 to 10, wherein said composition is an infant nutritional formula. 12. The nutritional composition for use of embodiment 11, wherein said composition comprises at least 0.0001 wt% any of synthetic compounds of formula (2) or (3), or a combination thereof, such as between about 5 mg / l and about 35mg / l, preferably between about 6 mg / l and about 26 mg / l of said compounds or said combination. 13. The synthetic compound for use of embodiment 1 or the nutritional composition for use according to any one of embodiments 3 to 11, wherein said compound or said composition increases the relative abundance of one or more following bacterial species in the young child gut microbiota: Bifidobacterium longum, Bifidobacterium breve, Bifidobacterium scardovii, Bacteroides caccae, Bacteroides uniformis, Bacteroides stercoris, Bacteroides xylanisolvens, Parabacteroides merdae, Faecalibacterium prausnitzii, Collinsella aerofaciens, Ruthenibacterium lactatiformans, Ruminococcus gnavus, Hungatella hathewayi. 14. The synthetic compound or nutritional composition for use of embodiment 13, wherein the compound or the composition - supports and / or promotes maturation of the immune system of the child; - reduces colonization of the child gut by a pathogenic bacterial species decreases the risk of said colonization; - maintains and / or improves the child gut barrier integrity; and / or - provides nutrients essential for the child growth and maturation, such as vitamins, amino acids, short-chain fatty acids. 15. The synthetic compound or nutritional composition for use according any of the preceding embodiments, wherein the young child is 1 day to 365 days old. Examples The examples described below are not limiting but for illustration purposes only. Example 1: General procedure for the production of a composition comprising a compound of formula (8) The 2,3-trans-sialidase catalyzed sialylation reaction is performed in an aqueous solution at a pH between about 6.0 to about 7.0. A typical reaction mixture contains the compound of formula (7) (1 eq.), 3’-sialyllactose (3.5 eq.), β-cyclodextrin (0.5 eq.), and 2,3-transialidase (TcTS, 0.4 g / L). The reaction mixture is stirred for about 3 to 6 hours at a temperature of about 37°C and then the β-galactosidase is added (0.13 g / L). The reaction mixture is nanofiltered using 300 to 500 Da membranes, a pressure of 15 to 20 bar and a temperature of about 30-40°C for about 6 to 8 hours. The nanofiltration retentate (NFR) is heated to a temperature between about 60 to 95°C for about 10 to 60 minutes. The NFR is then diafiltered (DF) using 250 kDa membranes, a pressure of around 15 to 20 bar, a temperature of about 15 to 40°C, and around 10 diafiltration volumes relative to the volume of the NFR. Example 2: General procedure for the production of a composition comprising a compound of formula (8) and of formula (10) The enzymatic reaction is performed in an aqueous solution at a pH between about 6.5 to about 7.5, and at a temperature of about 37oC. A typical reaction mixture contains the compound of formula (8) (1 eq.), N-acetylneuraminic acid (Neu5Ac, 2.5 eq.), β-cyclodextrin (0.525 eq.), ATP (3.5 eq.), CMP (0.27 eq.), MgCl2 (20 mM), and the following enzymes: sialyltransferase (CST-II I53A, 5g / L), cytidine monophosphate kinase (MtCMK, 12g / L), nucleoside diphosphate kinase (MtNDK, 6g / L), N- acylneuraminate cytidyltransferase (NmCSS, 1g / L), inorganic diphosphatase (EcPPase, 2.5 μL / mL). Example 3: General procedure for the production of a composition comprising a compound of formula (2) or compounds of formula (2) and (3) A composition comprising a compound of formula (8), or compounds of formula (8) and (10) is dissolved in methanol, and the triazine-based acylating agent is added. The resulting suspension is stirred at 50oC until a thin layer chromatography (TLC) analysis shows complete consumption of the starting material. Then, water is added, and the reaction mixture is cooled down to room temperature. A solid precipitates, which is filtered and dried in vacuum to obtain the final product. Example 4: Production of a composition comprising GM3 The composition comprising GM3 is synthesized in two steps. In the first step a composition comprising N-lyso-GM3 is obtained staring from lactosyl-D-erythro-sphingosine as described in Example 1. In the second step the composition comprising N-lyso-GM3 is subjected to N-acylation with the triazine- based acylating agent as described in Example (3). The triazine-based acylating agent is 4,6-dimethoxy-1,3,5-triazyn-2-yl stearate. The composition comprising GM3, produced by the process above, contains about 75-85 wt. % of ganglioside GM3 [α-N-acetylneuraminosyl-(2→3)-O-β-D-galactopyranosyl-(1→4)-β-D-glucopyranosyl- (1→1´)-N-stearoyl-D-erythro-sphingosine), about 5-10 wt.% by mass of LacCer[N(18) S(18)] [β-D- galactopyranosyl-(1→4)-β-D-glucopyranosyl-(1→1´)-N-stearoyl-D-erythro-sphingosine]; and about 0.4- 1 wt.% of GlcCer[N(18) S(18)] [β-D-glucopyranosyl-(1→1´)-N-stearoyl-d-erythro-sphingosine]. The GM3, LacCer and GlcCer all contain a C18fatty acid acylated to the sphingosine base. Example 5: Production of a composition comprising GM3 and GD3 The composition comprising GM3 and GD3 is synthesized in three steps. In the first step a composition comprising N-lyso-GM3 is obtained as described in Example 1. In the second step a composition comprising N-lyso-GM3 and N-lyso-GD3 is obtained as described in Example 2. In the third step the composition comprising N-lyso-GM3 and N-lyso-GD3 is subjected to N-acylation with the triazine- based acylating agent as described in Example 3. The composition comprising GM3 and GD3, produced by the process above, contains about 12-60 wt. % of ganglioside GM3 [α-N-acetylneuraminosyl-(2→3)-O-β-D-galactopyranosyl-(1→4)-β-D- glucopyranosyl-(1→1´)-N-stearoyl-D-erythro-sphingosine]; 20-55 wt. % of ganglioside GD3 [α-N- acetylneuraminosyl-(2→8)-α-N-acetylneuraminosyl-(2→3)-O-β-D-galactopyranosyl-(1→4)-β-D- glucopyranosyl-(1→1´)-N-stearoyl-D-erythro-sphingosine]; about 0-5 wt. % of ganglioside GT3 [α-N- acetylneuraminosyl-(2→8)-α-N-acetylneuraminosyl-(2→8)-α-N-acetylneuraminosyl-(2→3)-O-β-D- galactopyranosyl-(1→4)-β-D-glucopyranosyl-(1→1´)-N-stearoyl-D-erythro-sphingosine]; about 5-10 wt.% of LacCer[N(18) S(18)] [β-D-galactopyranosyl-(1→4)-β-D-glucopyranosyl-(1→1´)-N-stearoyl-D- erythro-sphingosine]; and about 0.4-1 wt.% of GlcCer[N(18) S(18)] [β-D-glucopyranosyl-(1→1´)-N- stearoyl-d-erythro-sphingosine]. The GM3, GD3, GT3 LacCer and GlcCer all contain a C18 fatty acid acylated to the sphingosine base. Example 6. Production of Enzymes The enzymes used for the production of the composition as described above are either purchased from commercial manufacturers or produced in-house by standard molecular cloning techniques using recombinant E. coli as the host. Example 7. The impact the compositions of the present invention on metabolite production in the gut of healthy infants. The objective of the study was to investigate the impact on metabolite production of healthy, exclusively formula-fed infants (1-3 months) by the different ganglioside compositions of the present invention. Three different ganglioside compositions were tested (test products), particularly one composition comprising GM3 (referred to as test product GM3), and two compositions comprising GM3 and GD3 (referred to as test product GM3-GD3 mix 1 and test product GM3-GD3 mix 2), wherein test products GM3-GD3 mix 1 and GM3-GD3 mix 2 were characterized by a different ratio of the two gangliosides. Particularly, GM3-GD3 mix 1 is characterized by a mass ratio between GM3 and GD3 of about 1:4, whereas GM3-GD3 mix 2 is characterized by a mass ratio between GM3 and GD3 of about 3:1. The three test products were tested as such or upon being subjected to gastric and small intestinal digestion / absorption prior to colonic incubation. The digested test products are referred to as GM3+, GM3-GD3 mix 1+, and GM3-GD3 mix 2+. Tests were performed using the ex vivo SIFR® technology, wherein the impact on metabolite production such as production of SCFA, lactate and bCFA, and key fermentation parameters such as pH and gas were assessed for 6 test subjects. The test products were compared against a no-substrate control, while predigested products and their undigested counterparts were also compared against each other. Test Study: Test products GM3, GM3-GD3 mix 1, GM3-GD3 mix 2, and their digested forms were tested at 1 g / L against a no-substrate control (NSC). The dose was determined based on a previous study showing that only minor effects on Bifidobacterium species were observed at 0.5 g / L, while dosing gangliosides at ≥ 1 g / L exerted pronounced effects. The test products were dosed as such or upon pre- digestion prior to colonic incubation. Test products, sample type, their corresponding compositions and doses are summarized in Table 1. Table 1. Test products, Sample Type, Compositions and Doses Dose Entry Test Product Type Composition [g / L] 1 Blank NSC No substrate 1 GM313.5 wt.% GD353.2 wt.% GM3-GD3 mix 1 2 Non-digested GT35.1 wt.% 1 (A)* LacCer[N(18)S(18)] 6.6 wt.% GlcCer[N(18)S(18)] 0.4 wt.% GM379.6 wt% GM3 3 Non-digested LacCer[N(18)S(18)] 7.4 wt.% 1 (B)* GlcCer[N(18)S(18)] 1 wt.% GM361.0 wt.% GM3-GD3 mix 2 GD322.0 wt.% 4 Non-digested 1 (C)* LacCer[N(18)S(18)] 7.3 wt.% GlcCer[N(18)S(18)] 0.5 wt.% GM3-GD3 mix 1 + 5 Digested Before digestion as for entry 2 1 (A+)* GM3 + 6 Digested Before digestion as for entry 3 1 (B+)* GM3-GD3 mix 2 + 7 Digested Before digestion as for entry 4 1 (C+)* *Abbreviations used in the schematic presentation of the study shown in Figure 1 The digested test products were subjected to gastric and small intestinal digestion procedures according to the method adapted to the infant gut published by Ménard et al., Food Chem.2018, 240, 338–345. Subsequently, small intestinal absorption was stimulated by means of a 1.0 kDa dialysis membranes resulting in absorption of gangliosides (size = 1.6 kDa) only upon their digestion to fractions <1.0 kDa. The colonic fermentation of the test products by the infant gut microbiota was investigated using the SIFR® technology (Cryptobiotix). The study design is schematically presented in Figure 1. An ex vivo SIFR® study was implemented, simulating colonic fermentation of test products by the gut microbiota derived from healthy infants (n = 6). An ex vivo SIFR® study was implemented, simulating colonic fermentation of test products by the gut microbiota derived from healthy infants (n = 6). Faecal samples were collected according to a procedure approved by Ethics Committee of the University Hospital Ghent (reference number BC-09977). The selection criteria for the donors were as follows: healthy infants of 1-3 months. The exclusion criteria were breastfeeding for more than 1 month in the past and 2 weeks prior to faecal donation, antibiotic use in 30 days before sample delivery for the study and previous NEC or gut surgery. This resulted in the enrolment of 6 specific test subjects (Table 2). The average age of the infants was 2.2 (± 1.0) months. The simulation parameters were as follows: • Test Product = 7 • No substrate control (NSC) = background medium + microbiota (no product) • Undigested products: GM3, GM3-GD3 mix 1, GM3-GD3 mix 2 • Predigested products: GM3 +, GM3-GD3 mix 1 +, GM3-GD3 mix 2 + • Time points = 0h (only for NSC), 24 h (all test products) Key fermentation parameters and metabolite production were measured at 0 h (only NSC) and 24h (for all test products). During the current study, acetate, propionate, butyrate, valerate and branched chain fatty acids (bCFAs) (sum of isobutyrate, isovalerate and isocaproate) were determined via a GC-FID approach. Lactate was measured with a high-throughput spectrophotometric method. Further, pH and gas production were also measured as key markers for microbial metabolic activity. For exploratory evaluation of the obtained results, a series of principle component analysis (PCA) was performed. The two principal components with the largest eigenvalues were plotted. For the statistical evaluation of the treatment effects on key fermentation parameters, cell counts, microbial diversity (4 indices) and microbial composition (phylum level) across 6 different donors, a repeated measures ANOVA analysis was performed (~ based on paired t-testing, thus accounting for fact that values are compared between samples of a given donor). The statistical significance of the potential treatment effects was determined via Benjamini-Hochberg post hoc testing30. Test Study Results • Undigested test product (GM3-GD3 mix 1, GM3 and GM3-GD3 mix 2) The treatment of the undigested GM3-GD3 mix 1, GM3 and GM3-GD3 mix 2 resulted in the following key observations: ─ pH Tended to decrease (not significant), while gas production tended to increase, most significantly for GD3 (+28%). ─ Significant increase in total SCFA production, with the highest increase observed for GM3- GD3 mix 1 (+14.7%), followed by GM3-GD3 mix 2 (+10.6%) and GM3 (+6.0%). This is largely attributed to a significant increase in acetate production for GM3-GD3 mix 1 (+19.0%), GM3-GD3 mix 2 (+14.2%) and GM3 (+8.1%). ─ Propionate levels tended to decrease (-3.9% for GM3-GD3 mix 1, -2.0% for GM3-GD3 mix 2 and -0.6% for GM3), while butyrate levels tended to increase (+28.2% for GM3-GD3 mix 1, +12.5% for MIX and +7.1% for GM3), bCFA significantly decreased, with the strongest decrease observed for GM3 (-8.3%), followed by GM3-GD3 mix 1 (-7.5%) and GM3-GD3 mix 1 (-5.6%). • Predigested test products (GD3+, GM3+ AND MIX+) Compared to the undigested counterpart (GM3-GD3 mix 1, GM3 and GM3-GD3 mix 2), the treatment of the predigested GM3-GD3 mix 1+, GM3+ and GM3-GD3 mix 2+ resulted in the following key observations: ─ Stronger decrease in pH with lower increase in gas production. ─ Lower increase in total SCFA production: GM3-GD3 mix 1+ (+11.6%), GM3-GD3 mix 2+ (+7.1%) and GM3+ (+5.9%). ─ Similarly, lower increase in acetate production was observed for : GM3-GD3 mix 1+ (+17.1%), GM3-GD3 mix 2+ (12.1%) while higher increase observed for GM3 (+10.7%) - Stronger decrease in propionate, especially for GM3-GD3 mix 2+ (-8.1%), followed by GM3- GD3 mix 1+ (-6.2%) and GM3+ (-5.1%). ─ Lower increase in butyrate: GM3-GD3 mix 1+ (+19.8%), GM3-GD3 mix 2+ (+5,9%), GM3+ (+1.0%) ─ Significantly stronger decrease in bCFA: GM3+ (-36.3%), GM3-GD3 mix 1+ (-28.4%) and GM3-GD3 mix 2+ (-22.0%) Discussion & Conclusion Upon simulating a single intake, the gangliosides impacted microbial metabolite production, i.e. decreased pH and increased gas production, significantly increased acetate levels, while tending to increase butyrate levels (thus also significantly increasing total SCFA). These stimulatory effects were the most and the least pronounced for GM3-GD3 mix 1 / GM3-GD3 mix 1+ and GM3 / GM3+, respectively, while GM3-GD3 mix 2 / GM3-GD3 mix 2+ exerted intermediate effects. Gut bacteria such as Bifidobacterium spp. present in infant’s gut are capable of degrading milk gangliosides and releasing sialic acid. Sialic acid is a functional sugar that is used as a fermentation substrate by a number of gut bacteria, many of which promote SCFA production. Since GM3-GD3 mix 1 has a higher content of GD3 which contains more sialic acid residues compared to GM3 per unit mass (2 vs 1), GM3-GD3 mix 1 could provide more nutrients for microbial fermentation, especially by SCFA- producing bacteria. In addition, the stimulatory effects on acetate and butyrate (thus, total SCFA) were only slightly reduced when gangliosides were subjected to upper GIT passage, e.g., +11.6% more total SCFA for GM3-GD3 mix 1+ compared to +14.7% for GM3-GD3 mix 1. This suggests that gastric and small intestinal digestion has only a minor impact on the stimulatory effects on gangliosides on health related SCFAs production. Interestingly, all test products tended to decrease propionate and bCFA production. In contrast to the stimulatory effects on acetate and butyrate, these inhibitory effects of the tested products are significantly enhanced by simulated oral, gastric, and small intestinal digestion. For example, bCFAs production decreased of -8.3% on average for undigested GM3 while decreased -36.3% for predigested GM3+. Overall, the tested products strongly stimulated acetate and butyrate levels, thus increasing total SCFA production. The strength of these stimulatory effects ranked as follows: GM3-GD3 mix 1 > GM3-GD3 mix 2 > GM3. These effects were only mildly reduced by the pre-digestion prior to colonic incubation. In contrast, propionate and bCFAs production decreased in response to all test products and were further lowered by the pre-digestion of the test products when compared to the undigested counterparts. Overall, the obtained results suggest that the compositions of the present invention impact microbial metabolite production. Besides increasing acetate / butyrate production, the compositions of the present invention lowered propionate / bCFAs levels, potentially resulting in a series of health benefits for the human host. Pre-digestion only had minor effects on the increase of acetate / butyrate levels, while significantly further decreasing propionate / bCFA levels. Example 8. The impact compositions of the present invention on infant gut microbiota The research objective of the study was to investigate the impact of compositions of the invention on the composition of the gut microbiota of healthy, exclusively formula-fed infants (1-3 months) by two different gangliosides and the combination thereof. Three different ganglioside compositions were tested (test products), particularly one composition comprising GM3 (referred to as test product GM3), and two compositions comprising GM3 and GD3 (referred to as test product GM3-GD3 mix 1 and test product GM3-GD3 mix 2), wherein test products GM3-GD3 mix 1 and GM3-GD3 mix 2 were characterized by a different ratio of the two gangliosides. Particularly, GM3-GD3 mix 1 is characterized by a mass ratio between GM3 and GD3 of about 1:4, whereas GM3-GD3 mix 2 is characterized by a mass ratio between GM3 and GD3 of about 3:1. The three test products were tested as such or upon being subjected to gastric and small intestinal digestion / absorption prior to colonic incubation. The digested test products are referred to as GM3+, GM3-GD3 mix 1+, and GM3-GD3 mix 2+. Using the ex vivo SIFR® technology, the impact on and microbial composition (quantitative 16S rRNA gene profiling) was assessed for 6 test subjects. The test products were compared against a no-substrate control, while predigested products and their undigested counterparts were also compared against each other. The study design and ganglioside compositions are described in Example 7. Microbial composition analysis (quantitative 16S rRNA gene profiling) were performed at 0h (no substrate control (NSC)) and 24h (all test arms). Upon DNA extraction, library preparation and sequencing were performed on an Illumina MiSeq platform with v3 chemistry. The 16S rRNA gene V3-V4 hypervariable regions were amplified using primers 341F (50 -CCT ACG GGN GGC WGC AG-30) and 785Rmod (50 -GAC TAC HVG GGT ATC TAA KCC-30). Results were analysed at different taxonomic levels (phylum, family and OTU level). For taxonomic analysis, the proportional data derived from sequencing (%) were corrected for the total amount of cells present in each sample (detected via flow cytometry), allowing to obtain more representative insights in the impact of interventions on the gut microbiota. For exploratory evaluation of the obtained results, a series of principle component analysis (PCA) was performed. The two principal components with the largest eigenvalues were plotted. For the statistical evaluation of the treatment effects on key fermentation parameters, cell counts, microbial diversity (4 indices) and microbial composition (phylum level) across 6 different donors, a repeated measures ANOVA analysis was performed (~ based on paired t-testing, thus accounting for fact that values are compared between samples of a given donor). The statistical significance of the potential treatment effects was determined via Benjamini-Hochberg post hoc testing30. The latter involves that a correction for multiple comparisons was implemented where p-values were adjusted by multiplying them with the total number of comparisons divided by the rank of each original p-value (across all p-values). In this specific case, 9 comparisons were considered (= 6 comparisons (NSC vs.6 treatments) + 3 comparisons (undigested vs predigested). In practice, this means that while the largest obtained p-value remained uncorrected (i.e., multiplied 1), the lowest p-value was multiplied with 9, thus strongly decreasing the chance of type 1 errors (i.e., false positives). In addition, the resulting series of adjusted p-values was rendered non-decreasing (i.e., when an adjusted p-value was higher than any of the subsequent adjusted p-values, its value was equalled to this lowest value). This generates a false discovery rate threshold allowing to estimate and control the chance of type 1 errors (i.e., false positives). For the statistical evaluation of the treatment effects on microbial composition (family and OTU level), the Benjamini-Hochberg correction was applied within each comparison, given the large number of features analyzed. As a remark, for statistical analysis of the quantitative 16S rRNA gene profiling, a value below the limit of quantification (LOQ) was equaled to the LOQ. Then, statistics was performed based on log- transformation of the absolute values (to render the data normally distributed). To establish an overall LOQ, first, 1 read was divided by the total amount of reads in each sample, followed by multiplication with the bacterial cell count detected via flow cytometry. This allowed to obtain a LOQ for each sample individually. Then, the highest LOQ was used as overall LOQ of the entire dataset. Further, regularized Canonical Correlation Analysis (rCCA) was performed to highlight correlations between metabolites and compositional data (at family and OTU level). Regarding compositional data, log-transformed, absolute phylogenetic data was used as input. rCCA was executed using the mixOmics package with the shrinkage method for estimation of penalization parameters in R project.org / ). Results 1. Background on key phyla / families / species of the human gut microbiome. The Actinobacteria phylum mainly consists of Bifidobacteriaceae and Coriobacteriaceae. The Bifidobacteriaceae family contains many known health-related species, able to produce acetate and lactate39. Collinsella species are on the other hand the most abundant Coriobacteriaceae membersandproduce H2gas, formate, acetate and lactate. The Bacteroidetes phylum contains versatile glycan- fermenting members. Key families are the Bacteroidaceae and Prevotellaceae, two families considered to be main differentiators between the so-called enterotypes29. Bacteroides species produce acetate and propionate and doing so also succinate (as intermediate of propionate production)40. Other families are Rikenellaceae, Tannerellaceae and Porphyromonadaceae. Further, the Firmicutes phylum contains a diverse series of phyla including, amongst others: • Acidaminococcaceae: a key species of this family is Phascolarctobacterium faecium, an abundant colonizer41that is able to convert succinate into propionate42• Erysipelotrichaceae (e.g., Eubacterium biforme) and Christensenellaceae (e.g., C. minuta) • Lachnospiraceae: contains several important butyrate-producing species such as Anaerobutyricum hallii43, Anaerostipes44, Butyrivibrio, Coprococcus, Eubacterium rectale, Roseburia. Further, Lachnospiraceae are among the first to be established in the gastrointestinal tract, with Ruminococcus gnavus being the exclusive representative of this family in 2-months old breast-fed infants. Further, this family also contains Dorea spp., which is a major gasproducer(H2 / CO2) related to IBS . • Ruminococcaceae: several important butyrate-producing species such as Butyricicoccus pullicaecorum, Gemmiger formicilis, Faecalibacterium prausnitzii and Subdoligranulum variable; • Selenomonadaceae: Megamonas species; • Veillonellaceae: lactate-converting, acetate / propionate / H2-producing species such as Veilonella; • As a remark, Enterococcaceae, Lactobacillaceae and Streptococcaceae are Firmicutes families containing lactic acid producing member that typically colonize the upper GIT but to much lower extent the colon. While Proteobacteria mainly contain opportunistic pathogens (e.g., Escherichia coli), Verrucomicrobia has the health-related, mucin-degrading, acetate / propionate-producing Akkermansia muciniphila as its main representative. Finally, besides bacteria, there are also Archaeasuch as Methanobrevibactersmithii colonize the human gut. M. smithii converts H2 / CO2to CH4. Other H2and / or CO2consumers are acetogens (Blautia hydrogenotrophica; Lachnospiraceae member) and sulphate reducers (Desufovibrio piger: Proteobacteria member that converts H2 / SO4to H2S). 2. Donor characterization (0h) A PCA at family level (explaining a large portion of the variation (92.7%)) demonstrated that there were marked differences in microbial composition between the 6 infants at baseline. First, all infants except infant 5 had high levels of Bifidobacteriaceae, a dominant member of the infant microbiota49, with levels being particularly high for infants 2 / 4 that thus positioned to the left side of the PCA. In contrast, infants 5 positioned to the right due to high levels of rather Bacteroidaceae / Lachnospiraceae. Finally, infants 1 / 3 / 6 had intermediate Bifidobacteriaceae levels, along with donor-dependent taxa such as, amongst others, Coriobacteriaceae (infant 1 and particularly infant 3), Enterobacteriaceae (infant 1) and Ruminococcaceae (infant 6). Overall, the marked differences in microbiota composition at baseline stress that infants used during the current study covered the broad range of microbiota composition that occurs in vivo, thus ensuring representative findings, which cannot be obtained when incorporating only one or a limited number of test subjects. 3. Cell density and diversity Analysis of the total cell numbers across the different samples demonstrated that all products tended to increase total bacterial cell density, albeit not significantly due to the large interpersonal differences across the different infant donors. On average, the increase in cell density was more pronounced for the predigested gangliosides compared to their undigested counterparts. Four diversity indices (the observed number of operational taxonomic units (OTUs), i.e. groups of closely related bacterial species), the Chao1 diversity index, the reciprocal Simpson diversity index and the Shannon diversity index, were calculated to obtain optimal insights into microbial diversity. First, both the observed number of species and the Chao1 diversity index were calculated as measures of species richness. As the Chao1 diversity index estimates the number of missing species (and thus “counts the uncountable”), this index is likely the most appropriate measure for species richness for the current dataset. While the observed number of OTUs tended to decrease for all the products, Chao1 diversity index tended to increase for GM3-GD3 MIX 2 and especially GM3-GD3 MIX 2+ . Further, two additional indices were based on both species’ richness and evenness (reciprocal Simpson diversity index and Shannon diversity index). These indices are based on the dominant community members and have higher values if these dominant members are more evenly distributed. A significant increase in both indices was observed for GM3-GD3 MIX 1. In addition, the predigested GM3-GD3 MIX 1+ also tended to decrease both indices significantly compared to GD3. Overall, this suggests that gangliosides support a broad range of gut microbes (see Example 7, Table 1 for a detailed description of the test compounds). 4. Changes in microbial composition To obtain insight into the main changes in microbial composition, a principal component analysis (PCA) was performed based on the absolute levels (cells / mL) of the most abundant families5. The PCA was not based on standardized data but on centered data, thus reducing the mean level of each family to 0 yet retaining the actual standard deviation. This approach with centred data allows to zoom in on the shifts in the most abundant families. The PCA provided comprehensive insight given that the first two components alone already explained 96.8% of the variation of the dataset. With respect to the impact of time, there was a marked differential clustering of 0h and 24h samples, demonstrating the growth of the infant gut microbes along the 24h incubations. Further, treatment effects were observed upwards along PC2. While they will be elaborated in much more depth in the next section, a pronounced effect of GM3-GD3 MIX1 and GM3-GD3 MIX 1+ seemed to be a stimulatory effect on Ruminococcaceae, while other product- specific effects were driven by Bifidobacteriaceae and Bacteroidaceae members. 5. Exploratory analysis of treatment effects To focus on treatment effects in more detail, a PCA analysis was performed at the highest phylogenetic resolution (OTU level) and at 24h only, thus removing the noise caused by time. Interestingly, all test products positioned distinctly different from the NSC, suggesting pronounced effects of the gangliosides on microbial composition: • First, positioning was mostly driven by ganglioside type (GM3-GD3 MIX 1, GM3 or GM3-GD3 MIX2) and not based on whether gangliosides were previously subjected to an upper GIT simulation, suggesting that gangliosides are largely resistant to digestion / absorption • GM3-GD3 MIX2 / GM3-GD3 MIX2+ exerted effects on microbial composition that were intermediate between those of GM3-GD3 MIX 1 / GM3-GD3 MIX 1+ and GM3 / GM3+: o The stimulation of Ruminococcaceae by GM3-GD3 MIX 1 / GM3-GD3 MIX 1+ was due to the increase of the butyrate producing Faecalibacterium prausnitzii. Further, GM3-GD3 MIX 1 / GM3-GD3 MIX 1 also stimulated two Bacteroidaceae members (Phocaeicola massiliensis and Bacteroides stercoris along with Hungatella hathewayi. o GM3 / GM3+ rather related to, amongst others, Parabacteroides distasonis and Bacteroides dorei / vulgatus Remark: an additional PCA (based on non-log transformed absolute levels (cells / mL), thus focusing on only highly abundant OTUs) revealed the involvement of also Bifidobacterium species (e.g. Bifidobacterium longum in fermentation of gangliosides. Overall, the exploratory analysis revealed marked effects of the test products on microbial composition. To statistically support these findings, the data was further processed at three phylogenetic levels, i.e., phylum, family and OTU level. 6. In-depth analysis of treatment results a. Phylum A targeted analysis was performed for key phyla (Actinobacteriota, Bacteroidota, Firmicutes) and 2 additional minor phyla (Proteobacteria and Verrucomicrobiota) that were detected across the 6 infants. This revealed following key treatment effects: • Significant increase in Firmicutes for all products, especially for GD3 / GD3+; • Higher increase in Actinobacteriota for predigested products, compared to the undigested ones; • Increase in Bacteroidota for all products. b. Family and OTUs To gain insight in treatment effects at family and OTU level, key taxa were displayed in heat maps based on the log2(average fold change of treatment vs. NSC) (not shown), meaning that positive valuesindicatean increase, while negative values a decrease due to treatment. Further, at both taxonomic levels, a rCCA was performed to highlight correlations between key fermentation parameters and specific taxa. Owing to interpersonal differences and treatment effects, correlations could be established between specific metabolites and certain taxa, in line with known metabolic capabilities of these taxa. As published recently, such approach allows to build hypothesis on mode-of-action (Van den Abbeele, P. et al. Bridging preclinical and clinical gut microbiota research using the ex vivo SIFR technology. Front Microbiol (2023) doi: 10.3389 / fmicb.2023.1131662). Given the large interpersonal differences across the 6 infants at OTU level, strong correlations were mostly established at family level: • Acetate ~ acetate producers in the family Bacteroidaceae54. In addition, 3 OTUs related to Bifidobacterium species also correlated with acetate production. • Propionate ~ propionate producers belonging to: o Bacteroidaceae (including 3 Bacteroides spp.) o Veillonellaceae (including Veillonella parvula) • Butyrate ~ butyrate producers belonging to o Coriobacteriaceae (including Collinsella aerofaciens) o Lachnospiraceae (including Hungatella hathewayi) o Ruminococcaceae (including Faecalibacterium prausnitzii, Ruthenibacterium lactatiformans) A selection of infant health relevant OTUs is summarized in the Table 2 below (Upward and downward arrows indicate marked increase or decrease, respectively. Noted correlations with SCFA production were also indicated (Ac: acetate, Pro: propionate, But: butyrate). Table 2. Undigested Predigested GM3- GM3 GM3- GM3- GM3+ GM3- Correlation w / GD3 GD3 GD3 GD3 KFP (rCCA) MIX1 MIX2 MIX1+ MIX2+ HEALTH-RELATED OTUS Bifidobacterium longum↑ ↑ -Bifidobacterium breve↑ ↑ ↑ ↑ AcBifidobacterium scardovii↑ ↑ ↑ ↑ ↑ AcBacteroides dorei / vulgatus↓ ↓ -Bacteroides caccae↑ ↓ ProBacteroides uniformis↑ ↓ Ac / ProBacteroides stercoris↑ ↑ ProBacteroides xylanisolvens↑ ↑ ↑ ↑ -Parabacteroides distasonis↓ ↑ ↓ ↑ -Parabacteroides merdae↑ ↑ ↑ Ac / ProFaecalibacterium prausnitzii↑ ↑ ↑ ↑ ↑ ↑ -OTHER OTUs Collinsella aerofaciens↑ ↑ ButRuthenibacterium lactatiformans↑ ↑ ↑ ↑ ↑ ↑ ButRuminococcus gnavus↑ -Hungatella hathewayi↑ ↑ ↑ ↑ ↑ ButVarious test products stimulated OTUs related to two ‘infant type’ Bifidobacterium species, i.e., B. longum and B. breve, along with a third species B. scardovii • GM3 exerted stronger bifidogenic effects compared to GM3- GD3 MIX1 • Stronger stimulatory effects were observed for predigested gangliosides, most noticeable when comparing GM3-GD3 MIX1+ to GM3-GD3 MIX1 • Remarkably, GM3-GD3 MIX2 more strongly stimulated B. breve compared to the individual gangliosides, suggesting a synergy between GM3-GD3 MIX1 and GM3 Bifidobacterium spp. are the main acetate and lactate producers of the infant gut microbiota and are also known to cross-feed with other SCFA producing bacteria. Additionally, the effects on the OTUs were more consistent across the different donors for the pre-digested products compared to the undigested ones. GM3-GD3 MIX1 / GM3-GD3 MIX1+ also significantly increased Collinsella aerofaciens. In a recent study, a C. aerofaciens subspecies was demonstrated to be able to synthesize butyrate. In the current study, C. aerofaciens correlated with butyrate production, suggesting that C. aerofaciens may play a role in enhancing butyrate production upon ganglioside consumption. Further, multiple OTUs related to Bacteroides species (acetate / propionate producers) markedly responded to various treatments and positively correlated with SCFA production: • Bacteroides dorei / vulgatus • Bacteroides caccae ~ propionate • Bacteroides uniformis ~ acetate, propionate • Bacteroides stercoris ~ propionate • Bacteroides xylanisolvens GM3 and GM3-GD3 MIX1 exerted very different effects on these Bacteroides species. While GM3 tended to increase Bacteroides dorei / vulgatus, GM3-GD3 MIX1 inhibited this species and instead stimulated the 4 other OTUs. Further, GM3-GD3 MIX1, but not GM3-GD3 MIX1 + stimulated B. caccae, B. uniformis and B. stercoris. Bacteroides species have been shown - to have protective anti-inflammatory responses during viral infections (Ramakrishna, C. et al. Bacteroides fragilis polysaccharide A induces IL-10 secreting B and T cells that prevent viral encephalitis. Nat Commun 10, 2153 (2019)), prevention of colitis (Shen, Y. et al. Outer membrane vesicles of a human commensal mediate immune regulation and disease protection. Cell Host Microbe 12, 509–520 (2012)), and translocation of pathogens (Vernay, T. et al. Bacteroides fragilis prevents Salmonella Heidelberg translocation in co-culture model mimicking intestinal epithelium. Benef Microbes 11, 391–401 (2020)), limitation of susceptibility to asthma induction (Johnson, J. L., Jones, M. B. & Cobb, B. A. Bacterial capsular polysaccharide prevents the onset of asthma through T-cell activation. Glycobiology 25, 368–375 (2015)), while also having been associated with favorable anticancer immune responses (Routy, B. et al. The gut microbiota influences anticancer immunosurveillance and general health. Nat Rev Clin Oncol 15, 382–396 (2018)). OTUs related to acetate / propionate producing Parabacteroides species (in the family Tannerellaceae) also responded differently to the different treatments: • Parabacteroides distasonis strongly decreased for GM3-GD3 MIX1 / GM3-GD3 MIX1 +but increased for GM3 / GM3+ • Parabacteroides merdae specifically increased for GM3-GD3 MIX1 / GM3-GD3 MIX1+, (and correlated with propionate production) • Parabacteroides species have recently been proposed as next-generation probiotics given their potent anti-inflammatory effects and anti-obesity potential (Wang, K. et al. Parabacteroides distasonis Alleviates Obesity and Metabolic Dysfunctions via Production of Succinate and Secondary Bile Acids. Cell Rep 26, 222-235.e5 (2019); Cuffaro, B. et al. In Vitro Characterization of Gut Microbiota-Derived Commensal Strains: Selection of Parabacteroides distasonis Strains Alleviating TNBS-Induced Colitis in Mice. Cells 9, E2104 (2020)). While aforementioned Actinobacteriota and Bacteroidota members were involved in ganglioside fermentation, the Firmicutes was most strongly affected by ganglioside treatment (as mentioned above, this phylum significantly increased for all treatments). At family level, this increase of Firmicutes followed from strong increases of multiple families, most notably Ruminococcaceae, Lachnospiraceae, and Erysipelotrichaceae. First, OTUs related to two members of Ruminococcaceae significantly increased upon all treatments for specific donors: • Faecalibacterium prausnitzii is one of the main butyrate producers of the human gut microbiota and has been linked with health benefits that extend well beyond butyrate production and are e.g. mediated via a protein called Microbial Anti-inflammatory Molecule (MAM) (Breyner, N. M. et al. Microbial Anti-Inflammatory Molecule (MAM) from Faecalibacterium prausnitzii Shows a Protective Effect on DNBS and DSS-Induced Colitis Model in Mice through Inhibition of NF-κB Pathway. Frontiers in Microbiology 8, (2017)). F. prausnitzii strongly increased for donor 6 and donor 1 (upon GD3 / GD3+ treatment). Notably, butyrate levels and F. prausnitzii levels of donor 6 followed the same trend, suggesting that F. prausnitzii is the key butyrate producing species upon GM3-GD3 MIX1 / GM3-GD3 MIX1 + treatment for this donor. • Ruthenibacterium lactatiformans: potent lactate producer (Shkoporov, A. N. et al. Ruthenibacterium lactatiformans gen. nov., sp. nov., an anaerobic, lactate-producing member of the family Ruminococcaceae isolated from human faeces. Int J Syst Evol Microbiol 66, 3041– 3049 (2016)), increased for donor 1 and 3. Interestingly, these two donors exhibited the highest lactate levels among all the donors- that increased for GM3 / GM3+ / GM3-GD3 MIX2 / GM3-GD3 MIX2+ Within the Lachnospiraceae, gangliosides (particularly GM3-GD3 MIX1 and / or GM3-GD3 MIX1+) increased following two OTUs: • Ruminococcus gnavus: interestingly, along with Bifidobacteriaceae, Lachnospiraceae are among the first to be established in the gastrointestinal tract of infants, with Ruminococcus gnavus being the exclusive representative of this family in 2-months old breast-fed infants45. This could, in part, be attributed to their ability to ferment gangliosides • Hungatella hathewayi: belonging to the family Lachnospiraceae. H. hathewayi were previously reported to produce acetate, lactate and butyrate. 7. Discussion and conclusions The research objectives of the study were to assess the impact of gangliosides on the gut microbiota of healthy, exclusively formula-fed infants (1-3 months). For this purpose, the impact on metabolic activity (pH, gas, SCFA, lactate and bCFA) and composition (quantitative 16S rRNA gene profiling) upon adding the gangliosides GM3-GD3 MIX1, GM3 and the combination thereof, to the colonic environment of infants, as simulated with the ex vivo SIFR® technology. The test products, three mixtures of GM3 and GD3 gangliosides containing different weight ratios each ganglioside (identified herein as GM3-GD3 MIX1, GM3 and GM3-GD3 MIX29, were tested upon being subjected to gastric and small intestinal digestion / absorption prior to colonic incubation (GM3-GD3 MIX1+ / GM3+ / GM3-GD3 MIX2+).6 different infants were included in the study design. In-depth analysis of microbial composition revealed that all the test products tended to increase bacterial cell density. While microbial diversity in terms of species richness tended to increase for GM3-GD3 MIX2 and especially GM3-GD3 MIX2+, species evenness significantly increased for GM3- GD3 MIX1, overall suggesting that gangliosides tend to support a broad range of gut microbes. First, all test products (except GM3-GD3 MIX1) displayed significant and / or consistent bifidogenic effects, increasing the abundance of OTUs related to Bifidobacterium longum, Bifidobacterium breve and / or Bifidobacterium scardovii (Saturio, S., et. al. 2021 Role of Bifidobacteria on infant health. Microorganisms. 9(12): 2415. doi:10.3390 / microorganisms9122415). A remarkable finding was that GM3-GD3 MIX2 most strongly stimulated B. breve, suggesting a synergistic effect between GD3 and GM3. Moreover, pre-digestion generally resulted in stronger bifidogenic effects. Another Actinobacteriota member, i.e., an OTU related to Collinsella aerofaciens - a potential butyrate producer – also increased for GM3-GD3 MIX1 / GM3-GD3 MIX1+. In addition, GM3-GD3 MIX1 exerted strong stimulatory effects on a number of OTUs related to acetate / propionate-producing Bacteroides spp., i.e., B. caccae, B. uniformis, B. stercoris, while B. xylanisolvens increased for all GD3 / GD3+-containing compositions. In contrast, GM3-GD3 MIX1 / GM3- GD3 MIX1+ strongly reduced the abundance of the OTU related to Bacteroides dorei / vulgatus. Similarly, GM3-GD3 MIX1 / GM3-GD3 MIX1+ also increased Parabacteroides merdae, while decreasing Parabacteroides distasonis. The effect of GM3-GD3 MIX1 on Bacteroidota members was highly species- specific. In contrast, GM3 did not lower levels of Parabacteroides distasonis and Bacteroides dorei / vulgatus. The most pronounced effect of the gangliosides was a strong increase of the phylum Firmicutes and its families. Most notably, the test gangliosides increased two OTUs in the family Ruminococcaceae which are related to Faecalibacterium prausnitzii and Ruthenibacterium lactatiformans for certain donors. These increases also correlated with the butyrate and lactate production by their gut microbiota. Some other notable OTUs that were significantly increased by the products related to Hungatella hathewayi (butyrate producer). Example 9. Child nutritional formula A child nutritional formula having the following composition is prepared: Nutrient Per 100kcal Per Liter Energy (kcal) 100 670 Protein (g) 1.83 12.3 Lipid (g) 5.3 35.7 Linoleic acid (g) 0.79 5.3 Α-linolenic acid (mg) 101 675 Lactose (g) 11.2 74.7 Minerals (g) 0.37 2.5 Vitamin A (μg RE) 105 700 Vitamin D (μg) 1.5 10 Vitamin E (mg TE) 0.8 5.4 Vitamin K1 (μg) 8 54 Vitamin C (mg) 10 67 Vitamin B1 (mg) 0.07 0.47 Vitamin B2 (mg) 0.15 1.0 Niacin (mg) 1.0 6.7 Vitamin B6 (mg) 0.075 0.5 Folic acid (μg) 9.0 60 Pantothenic acid (mg) 0.45 3.0 Vitamin B12 (μg) 0.3 2.0 Biotin (μg) 2.2 15 Ganglioside GM3 (mg) 1.5 10 Lactosyl ceramide (mg) 0.18 1.2 Glucosyl ceramide (mg) 0.09 0.6 The disclosure should not be seen in any way restricted to the embodiments described and a person with ordinary skill in the art will foresee many possibilities to modifications thereof. The above described embodiments are combinable. The following claims further set out particular embodiments of the disclosure.

Claims

CLAIMS 1. A synthetic compound of formula (1), or salt thereof:wherein R1is a C13-C17 alkyl chain; R2is a C13-C17,alkyl chain, preferably, C18alkyl chain, and R3is a carbohydrate moiety selected from: Neu5Acα2-3-Galβ1-4-Glcβ1-, or Neu5Acα2-8-Neu5Acα2-3-Galβ1-4-Glc β1-; for use in dietary treatment or prophylaxis of gut dysbiosis in a young child.

2. The synthetic compound for use according to claim 1, wherein the compound enhances the relative abundance of bacterial species of phyla Actinobacteriota, Bacteroidota and / or Firmicutes in the gut microbiome of the young child when an effective amount of the compound is administered to said child orally in one or more doses per day during at least 7 days.

3. A nutritional composition comprising one or more synthetic compounds of formula (1) for use according to claim 1 or 2.

4. The nutritional composition for use according to claim 3, comprising a synthetic compound of formula (2), or a salt thereof:wherein, R1and R2are defined as for the compound of formula (1).

5. The nutritional composition for use according to claim 3, comprising a synthetic compound of formula (3), or a salt thereof:wherein R1and R2are as defined as for the glycosphingolipid of formula (1) 6. The nutritional composition for use according to claim 3, comprising a synthetic compound of formula (2) and of formula (3), or salts thereof:wherein R1and R2are as defined as for the glycosphingolipid of formula (1).

7. The nutritional composition for use according to claim 6, wherein the ratio between the synthetic compound of formula (2) and the synthetic compound of formula (3) is from about 0.2:1 to about 14:1, preferably from about 0.2:1 to 5:

1.

8. The nutritional composition for use according to any one of claims 3 to 7, further comprising a synthetic compound of formula (4):wherein R1and R2are defined as for the compound of formula (1).

9. The nutritional composition for use according to any one of claims 3 to 8, further comprising a synthetic compound of formula (5):wherein R1and R2are defined as for the compound of formula (1).

10. The nutritional composition for use according to any one of claims 3 to 9, further comprising a synthetic compound of formula (6):(6) wherein R1and R2, Glc, Gal, and Neu5Ac are defined as for the compound of formula (1).

11. The nutritional composition for use of any one of claims 3 to 10, wherein said composition is an infant nutritional formula.

12. The nutritional composition for use according to claim 11, wherein said composition comprises at least 0.0001 wt% any of synthetic compounds of formula (2) or (3), or a combination thereof, such as between about 5 mg / l and about 35mg / l, preferably between about 6 mg / l and about 26 mg / l of said compounds or said combination.

13. The synthetic compound for use according to claim 1 or the nutritional composition for use according to any one of claims 3 to 11, wherein said compound or said composition increases the relative abundance of one or more following bacterial species in the young child gut microbiota: Bifidobacterium longum, Bifidobacterium breve, Bifidobacterium scardovii, Bacteroides caccae, Bacteroides uniformis, Bacteroides stercoris, Bacteroides xylanisolvens, Parabacteroides merdae, Faecalibacterium prausnitzii, Collinsella aerofaciens, Ruthenibacterium lactatiformans, Ruminococcus gnavus, Hungatella hathewayi.

14. The synthetic compound or nutritional composition for use according to claim 13, wherein the compound or the composition - supports and / or promotes maturation of the immune system of the child; - reduces colonization of the child gut by a pathogenic bacterial species decreases the risk of said colonization; - maintains and / or improves the child gut barrier integrity; and / or - provides to the child nutrients essential for the child growth and maturation, such as vitamins, amino acids, short-chain fatty acids. 15.The compound or composition for use according to any of the preceding claims, wherein the young child is from 1 day to 365 days old.