A novel animal feed additive composition

Abstract

An animal feed additive composition comprising: a) 45-65 % by weight, with respect to the total weight of the a)+b), of a butyric acid glycerol ester, said butyric acid glycerol ester comprising at least 75 % by weight of tributyrin, and b) 35-55% by weight, with respect to the total weight of the a)+b), of a valeric acid glycerol ester, said valeric acid glycerol ester comprising at least 30 % by weight of monovalerin.

Description

[0001] A NOVEL ANIMAL FEED ADDITIVE COMPOSITION

[0002] ***

[0003] DESCRIPTION

[0004] FIELD OF THE INVENTION

[0005] The present invention refers to a glycerol esters based animal feed additive composition for promoting the gastro-intestinal functionality in animals, thereby providing several beneficial effects such as not only promoting the gastro intestinal growth, improving the feed conversion ratio and the growth performance of said animals, but also improving the development of a apposite microbiota in the intestinal tract, reducing gastrointestinal microbial dysbiosis and the growth of harmful microbiota, as well as stimulating the growth of beneficial microbiota.

[0006] BACKGROUND OF THE INVENTION

[0007] It is well known in the art that different short and medium chain fatty acids have positive effects on animal health and performance in general. Utilizing glycerol esters of short and medium chain fatty acids is a technology to achieve the targeted delivery of these acids to the gastrointestinal tract of an animal. There are indeed several advantages associated with delivering said acids in the form of glycerol esters. Some of the acids, like propionic acid, butyric acid and valeric acid are either corrosive and / or have a pungent, unpleasant odor, which causes handling, safety, manufacturing and transport challenges. Said glycerol esters do not have these issues related to smell or corrosiveness. Delivering short and medium chain fatty acids to an animal in the form of glycerol esters is also a good way to transport the fatty acids to the lower regions of the gastrointestinal tract of an animal. Free short chain fatty acids are indeed likely to be absorbed to a degree in the higher regions of the gastrointestinal canal and will reach the cecum or large intestine in far lower concentrations than intended for an effective dose. Glycerol esters on the other hand will to a large extent reach these regions and a large proportion of the fatty acid will be released and thus absorbed in these regions.

[0008] Another environmental and also economical aspect is known in the industry as feed conversion ratio. Simply put, as much as possible of the feed given to animals should result in growth. Resources are spent on producing the animal feed, resources that cause release of carbon dioxide to the atmosphere, depletion of water resources and fertilization and use of insecticides and herbicides during the growing of the plants used. Harvest, transportation and preparation will cause further release of carbon dioxide and use of resources. It is, in the light of the above, important to obtain an effective use, i.e. efficient feed conversion ratio, of the prepared animal feed as it will reduce the amount needed and hence also decrease the impact on the environment.

[0009] In the feed industry, for a great many years it was practice to provide antibiotics in daily feed to animals as a prophylactic treatment. This practice is banned in many countries as it over time contributes to the emergence of multi-resistant bacteria which are very difficult to treat when affecting animal or man. It is accordingly very important to avoid use of antibiotics as far as possible.

[0010] SUMMARY OF THE INVENTION

[0011] The Applicant noted that feed additives capable of improving the gastro-intestinal functionality in animals and in particular bringing several benefits to the microbiota of said animals, would have positive effects on animal health and performance in general at the same time desirably helping the industry in radically reducing use of antibiotics.

[0012] It has been now found that a feed additive composition based on glycerol esters of butyric acid in combination with glycerol esters of valeric acid demonstrated to be suitable for improving the gastrointestinal functionality in animals, and particularly in improving the development of a apposite intestinal microbiota in the intestinal tract, reducing gastrointestinal microbial dysbiosis and the growth of harmful microbiota, as well as stimulating the growth of beneficial microbiota in said animals.

[0013] Particularly, the present invention relates, in a first aspect, to an animal feed additive composition comprising: a) 45-65 % by weight, with respect to the total weight of a)+b), of a butyric acid glycerol ester, said butyric acid glycerol ester comprising at least 75 % by weight of tributyrin, and b) 35-55% by weight, with respect to the total weight of a)+b), of a valeric acid glycerol ester, said valeric acid glycerol ester comprising at least 30 % by weight of monovalerin. Surprisingly, said animal feed additive composition is suitable in achieving a targeted delivery of said short chain fatty acids to the gastrointestinal tract of animals thus promoting their gastro-intestinal functionality not only by promoting the gastro intestinal growth, improving the feed conversion ratio and the growth performance of said animals, but also by improving the development of a apposite microbiota in the intestinal tract , reducing gastrointestinal microbial dysbiosis and the growth of harmful microbiota, as well as by stimulating the growth of beneficial microbiota of said animals. Thanks to these properties, the animal feed additive composition according to the invention is particularly suitable to improve animal health and performance of foremost young animals, bringing them several benefits among which, for example, the growth performance.

[0014] In a further aspect, the present invention relates to a granular feed additive for animal nutrition in which the animal feed additive composition according to the invention is loaded on a granular carrier.

[0015] Most of the advantages of the granular feed additive according to this aspect of the present invention have been already disclosed in relation to the use according to the first aspect of the present invention and are not herewith repeated. In addition, the granular feed additive allows the animal feed additive composition to be handled as a dry substance.

[0016] In a still further aspect, the present invention relates to an animal feed additive composition or a granular feed additive according to the above aspects of the invention for use in promoting the gastro-intestinal functionality in an animal.

[0017] Advantageously, the use according to this aspect of the invention entails at least one beneficial effect in the animals fed with the animal feed additive composition according to the first aspect of the invention, said beneficial effect being selected from the group consisting of:

[0018] - promotion of the gastro intestinal growth,

[0019] - improvement of the feed conversion ratio,

[0020] - improvement of the growth performance,

[0021] - improvement of the development of an apposite microbiota in the intestinal tract, - reduction of gastrointestinal microbial dysbiosis,

[0022] - reduction of the growth of harmful microbiota, and

[0023] - stimulation of growth of beneficial microbiota.

[0024] The advantages of the use according to this aspect of the present invention have been already disclosed in relation to the first aspect of the present invention and are not herewith repeated.

[0025] DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention relates, in a first aspect, to an animal feed additive composition comprising: a) 45-65 % by weight, with respect to the total weight of a)+b), of a butyric acid glycerol ester, said butyric acid glycerol ester comprising at least 75 % by weight of tributyrin, and b) 35-55% by weight, with respect to the total weight of a)+b), of a valeric acid glycerol ester, said valeric acid glycerol ester comprising at least 30 % by weight of monovalerin.

[0027] Surprisingly, the feed additive composition according to the invention, based on glycerol esters of butyric acid in combination with glycerol esters of valeric acid, is suitable in achieving a targeted delivery of said short chain fatty acids to the gastrointestinal tract of animals thus promoting their gastro-intestinal functionality not only by promoting the gastro intestinal growth, improving the feed conversion ratio and the growth performance of said animals, but also by improving the development of a apposite microbiota in the intestinal tract, reducing gastrointestinal microbial dysbiosis and the growth of harmful microbiota, as well as by stimulating the growth of beneficial microbiota of said animals.

[0028] In this way, the feed additive composition according to the invention demonstrated to be capable of improving the gastro-intestinal functionality in animals and in particular of bringing several benefits to their microbiota, with several positive effects on animal health and performance in general, at the same time desirably helping the industry in radically reducing use of antibiotics. Thanks to all these properties, the animal feed additive composition according to the invention is particularly suitable to improve the health and performance of foremost young animals, bringing them several benefits among which, for example, the growth performance.

[0029] Within the framework of the present description and in the subsequent claims, except where otherwise indicated, all the numerical entities expressing amounts, parameters, percentages, and so forth, are to be understood as being preceded in all instances by the term "about". As used herein, the term “about” will be understood by persons of ordinary skill in the art and will vary to some extent on the context in which it is used. As used herein when referring to a measurable value such as an amount, a temporal duration, and the like, the term “about” is meant to encompass variations of ±20% or ±10%, including ±5%, ±1 %, and ±0.1 % from the specified value, as such variations are appropriate to perform the disclosed methods.

[0030] Also, all ranges of numerical entities include all the possible combinations of the maximum and minimum values and include all the possible intermediate ranges, in addition to those specifically indicated herein below.

[0031] Unless defined otherwise, all technical and scientific terms used herein generally have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0032] As used herein, the articles “a” and “an” refer to one or to more than one (i.e. to at least one) of the grammatical object of the article. By way of example, “an element” means one element or more than one element.

[0033] The present invention may present in one or more of the above aspects one or more of the characteristics disclosed hereinafter.

[0034] According to the present invention, the animal feed additive composition comprises a butyric acid glycerol ester (component a) in combination with a valeric acid glycerol ester (component b).

[0035] In the animal feed additive composition according to the invention, said butyric acid glycerol ester represents from 45 to 65 % by weight, preferably from 50 to 60 % by weight, even more preferably from 53 to 58 % by weight, and said valeric acid glycerol ester represents from 35 to 55% by weight, preferably from 40 to 50 % by weight, even more preferably from 42 to 47 % by weight, with respect to the total weight of the sum of said butyric and valeric acids glycerol esters.

[0036] Within the framework of the present description and in the subsequent claims, the total weight of the sum of butyric acid glycerol esters (component a) and valeric acid glycerol esters (component b), is also referred to as the “the total weight of a)+b)”.

[0037] According to the present invention, the butyric acid glycerol ester comprises at least 75 % by weight, preferably at least 80 % by weight, even more preferably at least 85% by weight, still more preferably at least 90% by weight of tributyrin.

[0038] Preferably, the butyric acid glycerol ester comprises less than 25 % by weight, more preferably less than 20 % by weight, even more preferably less than 15 % by weight, still more preferably less than 10 % by weight of glycerol dibutyrate.

[0039] Preferably, the butyric acid glycerol ester comprises less 12 % by weight, more preferably less than 8 % by weight, even more preferably less than 6 % by weight, still more preferably less than 5% by weight of glycerol monobutyrate.

[0040] According to the present invention, the valeric acid glycerol ester comprises at least 30 % by weight, preferably at least 40 % by weight, more preferably at least 45 % by weight, even more preferably at least 50 % by weight, still more preferably at least 60 % by weight, still even more preferably at least 70 % by weight of monovalerin.

[0041] Preferably, the valeric acid glycerol ester comprises less than 70 % by weight, more preferably less than 60 % by weight, even more preferably less than 55 % by weight, still more preferably less than 50 % by weight, still even more preferably less than 40 % by weight, still even more preferably less than 30 % by weight of divalerin.

[0042] Preferably, the valeric acid glycerol ester comprises less than 25 % by weight, more preferably less than 12 % by weight, even more preferably less than 8 % by weight, still more preferably less than 6 % by weight, still even more preferably less than 5 % by weight, still even more preferably less than 3 % by weight of trivalerin.

[0043] Preferably, in the animal feed additive composition according to the invention the molar ratio butyric acid I valeric acid, in free or esterified form, ranges from 1 .5 to 2.5, more preferably from 1 .8 to 2.2.

[0044] Preferably, the animal feed additive composition according to the invention further comprises, with respect to the total weight of a)+b), 1 -15 % by weight, more preferably 1 -10 % by weight, even more preferably 2-8 % by weight, still more preferably 3-7 % by weight of an essential oil.

[0045] Preferably, said essential oil is selected from the group consisting of: cinnamic aldehyde, carvacrol, thyme oil, inulin, garlic oil, betanine, quilliaja saponin, D-limonene, orange oil and combinations thereof.

[0046] In a preferred embodiment, the animal feed additive composition according to the invention comprises, with respect to the total weight of a)+b), 3-4.5 %, more preferably 3.4-4.2 % by weight of cinnamic aldehyde and / or carvacrol and 1 -2.5 %, more preferably 1 .5-2.2 % by weight of D-limonene.

[0047] It is known in the art that glycerol fatty acid esters could have a tendency to hydrolyze over time, particularly in cases where water and ions are present. Glycerol esters of fatty acids may accordingly release part of their fatty acid and glycerol through hydrolysis while at the same time the respective triglycerides, diglycerides and monoglycerides remain in an equilibrium balance. The amount of free glycerol and of free fatty acids can advantageously be kept at levels well below desired limits of the animal feed additive composition through addition of an acid scavenger.

[0048] Preferably, the animal feed additive composition according to the invention comprises an acid scavenger, more preferably from 1 to 5 % by weight, even more preferably from 1 .5 to 3 % by weight, still more preferably from 1 .8 to 2.7 % by weight, still even more preferably from 2 to 2.5 % by weight of said acid scavenger, with respect to the total weight of a)+b).

[0049] Preferably, said acid scavenger is selected from the group consisting of magnesium oxide, zinc oxide, calcium oxide, calcium stearate, zinc stearate and a combination thereof. In this way, the content of glycerol and of free valeric and butyric acid could be easily controlled.

[0050] Preferably, the animal feed additive composition according to the invention comprises, with respect to the total weight of a)+b), less than 4 % by weight, more preferably less than 3.5 % by weight, even more preferably less than 3 % by weight of a free short chain fatty acid selected from the group consisting of valeric acid and butyric acid. In this way, handling, safety, manufacturing and transport challenges as well targeted delivery of the fatty acids of the feed composition to the gastrointestinal tract of the animal are desirably optimized. Preferably, the animal feed additive composition according to the invention comprises, with respect to the total weight of a)+b), less than 4 % by weight, more preferably less than 3.5 % by weight, even more preferably less than 3 % by weight of glycerol.

[0051] Preferably, the animal feed additive composition according to the invention further comprises a buffering agent, more preferably 1 - 15 % by weight, with respect to the total weight of a)+b), of said buffering agent.

[0052] Preferably, said buffering agent selected from the group consisting of an alkali metal formate, an alkali metal acetate, an alkali metal propionate or a combination thereof.

[0053] Preferably, said alkali metal is selected from the group consisting of sodium, potassium, calcium and combinations thereof.

[0054] In a further aspect, the present invention relates to a granular feed additive for animal nutrition in which the animal feed additive composition according to the invention is loaded on a granular carrier.

[0055] Most of the advantages of the granular feed additive according to this aspect of the present invention have been already disclosed in relation to the use according to the first aspect of the present invention and are not herewith repeated. In addition, the granular feed additive allows the animal feed additive composition to be handled as a dry substance.

[0056] In the granular feed additive, the animal feed additive composition according to the invention may be loaded on the granular carrier according to any technique known to the skilled person for that purpose, for example by absorption.

[0057] Preferably, in the granular feed additive according to this aspect of the invention said granular carrier is silica.

[0058] Preferably, in the granular feed additive according to this aspect of the invention said granular carrier comprises particles having an average particle size of 20-70 microns.

[0059] Preferably, in the granular feed additive according to this aspect of the invention the animal feed additive composition is loaded on the granular carrier in a weight ratio of 50-80 % animal feed additive composition to 20-50 % granular carrier.

[0060] In a still further aspect, the present invention relates to an animal feed additive composition or a granular feed additive according to the above aspects of the invention for use in promoting the gastro-intestinal functionality in an animal. That is to say, the present invention relates also to a method of promoting the gastrointestinal functionality in an animal by administering to said animal an animal feed additive composition or a granular feed additive according to the present invention.

[0061] Advantageously, the use or method according to this aspect of the invention entails at least one beneficial effect in the animals fed with the animal feed additive composition according to the present invention, said beneficial effect being selected from the group consisting of:

[0062] - promotion of the gastro intestinal growth,

[0063] - improvement of the feed conversion ratio,

[0064] - improvement of the growth performance,

[0065] - improvement of the development of a apposite microbiota in the intestinal tract,

[0066] - reduction of gastrointestinal microbial dysbiosis,

[0067] - reduction of the growth of harmful microbiota, and

[0068] - stimulation of growth of beneficial microbiota.

[0069] The advantages of the use or method according to this aspect of the present invention have been already disclosed in relation to the first aspect of the present invention and are not herewith repeated.

[0070] Preferably, said harmful microbiota comprises at least one microorganism belonging to a genus selected from the group consisting of: Prevotella, Sutterella, Campylobacter, Fusobacteriaceae, and Enterobacteriaceae.

[0071] Preferably, said beneficial microbiota comprises at least one microorganism belonging to a genus selected from the group consisting of: Prevotellaceae, Lahnospiraceae, Lachnospiraceae, Ruminococcaceae, Lactobacillaceae, and Bifidobacterium.

[0072] According to this aspect of the invention, the animal feed additive composition or of the granular feed additive is used or administered for promoting the gastro-intestinal functionality in an animal, preferably a mammal, more preferably a monogastric mammal, even more preferably a pig.

[0073] The animal feed additive composition as herein disclosed is particularly suitable to young animals where the intestine is still under development, thanks to the beneficial effects that the same can have on the development of a balanced and beneficial intestinal microbiota. It is indeed known that the intestinal microbiota needs to be adapted to the type of nutrient consumed. For example a suckling piglet will have, and will need to have a different intestinal microbiota than a weaned piglet consuming solid feed. The development of a sound intestinal microbiota together with the development of the intestine structure such as balanced villi / crypt ratio is very important to the future growth performance of the young pig. The animal feed additive composition of the present invention has shown to improve both of these features and thereby create a better start in life for the young pig.

[0074] In a preferred embodiment of the invention, when the animal is a pig, the same is a weaned piglet or a nursery pig, even more preferably in the pre-grower phase. In this way, the animal feed additive composition or of the granular feed additive according to the invention has demonstrated to assist said animal in the adaptation of the intestinal microbiota from nursing diet to solid feed diet, especially but not exclusively when it is in the pre-grower phase.

[0075] When used for or administered to weaned piglets or nursery pigs, the animal feed additive composition can suitably be administered in either of two regimes. A first regime is to start when a the young piglets are weaned at about 3 - 4 weeks of age and continue through the early grower stage when the pigs are about 2 - 3 months of age.

[0076] The second regime is known as creep feeding in the trade and this means that the suckling / nursing / lactating piglets are introduced early on to solid feed and continues until the pigs are about 2 - 3 months of age. In the second regime the piglets will be gradually weaned and suckling will be ended at about 1 - 2 months of age.

[0077] In both alternatives the animal feed additive composition of the present invention may advantageously be added to the solid feed where it will improve the adaptation from the sows milk to solid feed in respect of intestinal microbial flora as well as the integrity of the intestinal tract.

[0078] Preferably, in the use or method according to the present invention the animal feed additive composition or of the granular feed additive is administered to said animal in an amount of 0.25 - 1 .5 gram per kilogram of feed, more preferably 0.4 - 1 .5 gram per kilogram of feed, even more preferably in an amount of 0.6 - 1 .2 gram per kilogram of feed. Further features and advantages of the invention will appear more clearly from the following description of some preferred embodiments thereof, made hereinafter by way of the following non-limiting examples.

[0079] Embodiment examples

[0080] In order to prove the concept separate field studies were performed. These three studies will be presented separately as:

[0081] -Example 1 with tables 1 a - 1d

[0082] -Example 2 with tables 2a - 2d

[0083] -Example 3 with tables 3a -3d

[0084] Example 1

[0085] Experimental animals

[0086] 320 crossbreed DLY (Yorkshire x Landrace x Duroc) weaned piglets (castrates males and females, weaned at around 28 days of age with average body weight of 8 kg per piglets) were used in this trail, and allocated to the experimental treatments based on the gender (half males and half females) and weaned body weight (each piglets were weighed, and grouped based on the similar average body weight). The vaccination history of the piglets were recorded. Prior to the start of the study, the animals were examined for signs of illness or injury. Any that appeared to be in poor condition were removed from the study. Animals were assigned to their treatment groups in a randomized complete block design. All the pens, where the animals were kept in, were uniquely labelled.

[0087] Each animal was observed daily by the animal supervisor in its pen and any variation of its appearance, the appearance of its excreta or of its behavior will be noted. If an animal was in poor condition, it would be observed more frequently. Table 1a Experimental treatments.

[0088] Table 1b formulated composition.

[0089] The diets for each group were calculated to be iso-nutritive, and to meet or exceed the nutrient requirements recommended by NRC (2012) for pigs. The diets (pellet) and water were ad libitum available.

[0090] All diets were prepared under the direct supervision of qualified personnel. Test products were premixed with ground cereal before addition to the final mix to assure fine homogeneity. In order to avoid cross-contamination, control feeds were manufactured before those containing test items, and cleaning batches (e.g. cereals) were used before and in between manufacturing of diets for this trial according to internal cleaning standard operating procedures.

[0091] All diets were stored in a cool (<20QC) and dry place until used.

[0092] Experimental procedure

[0093] Performance parameters: Piglets body weight at weaning day (around 28 days of age), 2 weeks post weaning (PW, around 38 days of age), and ending day (4 weeks PW, or around 52 days of age). Corresponding Average weight gain (ADG), feed intake (ADFI), and feed convert ratio (FCR) in each period have been calculated.

[0094] General health records (diarrhea rate, etc.), was recorded daily. Results

[0095] Table 1 c

[0096] Effect of the feed additive composition according to the invention on growth performance of weaned piglets

[0097] ADFI = average daily feed intake (gram per day) ADG = average daily growth (gram per day) FOR = feed conversion ratio

[0098] Conclusions

[0099] It is clearly shown that the performance as daily growth of piglets provided with the animal feed additive composition in accordance with the present invention performed much better than the control group. Also more of the nutrients in the feed was effectively absorbed by the gastrointestinal tract of the piglets provided with the animal feed additive composition in accordance with the present invention. This means that the environmental footprint on the feed used will be improved as will the production economy for the pig farmer. The above data indicates that the villi / crypt ratio is improved and also that the intestinal microbiota will adapt quicker to solid feed post weaning in group B & C than for the control group A.

[0100] The average weight gain for group B was improved by 13% compared to the control group A after 28 days. For group C compared to the control group A the corresponding improvement was 7.5 %. The feed conversion ratio was improved by 1 1 .5% for group B compared to the control group A after 28 days while the improvement for group C was 10%.

[0101] Especially noteworthy is the average feed intake and average weight gain over the first 16 days where the average daily feed intake for group B was improved by 4.6% and for group C by 4%. The average daily growth was even more impressive where group B had an average daily growth 15% higher that the control group A. The corresponding improvement for group C was 12.4%.

[0102] Table 1 d

[0103] Effect of the compositions on diarrhea rate of weaned piglets

[0104] Conclusions

[0105] It is clear from the above data that diarrhea is more common during the first two weeks post weaning which is the initial period where villi / crypt ratio as well as change in a microbial composition adapted to solid feed in the intestinal tract is changing from the previous microbiota adapted to a nursing diet. It is also clear from the above data that group B and C have a radically reduced the occurrence of diarrhea compared to the control group A.

[0106] Example 2

[0107] At least 384 crossbreed (Landrace x Large White dam line and Pietrain sire line) weaned piglets (males and females) from M.G. Agropecuaria were used for the trial. The experimental animals were obtained from 3 consecutive batches of piglets delayed one week. They were weaned at ca. 24 days of age with an average weaning weight of ca. 6.5 kg. Piglets were fed a unique diet (the same creep-feed used during nursing) from weaning to the onset of the study 4 days after weaning (acclimatization period). Animals were allocated to single-sex pens (replicates) so each treatment consisted of an equal number of homogeneous replicates (regarding sex and initial body weight).

[0108] Prior to the start of the study, the animals were examined for signs of ill, health and injury. Any that appeared to be in poor condition was removed from the study. If this practice reduced the number of pigs below to that required for the study, it was rescheduled with a fresh batch of animals. All the pens where the animals were kept in were uniquely labelled (number of the room, number of the pen and treatment code). A Randomized Complete Block Design (RCBD) with 3 experimental treatments was used.

[0109] Table 2 a zeed composition

[0110] Table 2b Experimental treatments.

[0111] Table 2c formulated composition.

[0112] Results

[0113] Table 2 d

[0114] Effect of different esterified fatty acids on growth performance of weaned piglets

[0115] ADFI = average daily feed intake (gram per day) ADG = average daily growth (gram per day) FOR = feed conversion ratio

[0116] Conclusions

[0117] It is clearly shown that the performance as daily growth of piglets provided with the animal feed additive composition in accordance with the present invention performed much better than the control group. Also more of the nutrients in the feed was effectively absorbed by the gastrointestinal tract of the piglets provided with the animal feed additive composition in accordance with the present invention. This means that the environmental footprint on the feed used will be improved as will the production economy for the pig farmer. The above data indicates that the villi / crypt ratio is improved and also that the intestinal microbiota will adapt quicker to solid feed post weaning in group B & C than for the control group A. The average weight gain for group B was improved by 9.6% compared to the control group A after 28 days. For group C compared to the control group A the corresponding improvement was 4.5 %.

[0118] The feed conversion ratio was improved by 6.5% for group B compared to the control group A after 28 days while the improvement for group C was 2.5%.

[0119] Especially noteworthy is the average feed intake and average weight gain over the first 14 days where the average daily feed intake for group B was improved by 1 1 .7%. The average daily growth was even more impressive where group B had an average daily growth 49.6% higher that the control group A. The corresponding improvement for group C was 24.7%.

[0120] Example 3

[0121] A total of 240 28-day-old Duroc x Landrace x Yorkshire weaned piglets were randomly divided into 5 groups with 6 replicates per group and 8 pigs per replicate using a completely randomized block design. The trial lasted 28 days and followed the experimental design as defined in Table 3b; the diets were as follows: CON- basal diet, ZnO- basal diet supplemented with 2,000 mg / kg ZnO, EFA_500, EFA_750, and EFA_1000- basal diet supplemented with 500, 750, and 1 ,000 mg / kg composition according to the invention (see Table 3c). The diet formula (Table 3a) was compliant with the recommendations of Chinese standards (GB / T 39235-2020, Nutritional Requirements for 8-25 kg Piglets). The basal diet contained no antibiotics, ZnO, or other growth-promoting additives.

[0122] On day 0, 14, and 28, the body weight of piglets was measured and the average daily gain (ADG) of weaned piglets was calculated. Feed intake was recorded per pen throughout the experiment to calculate average daily feed intake (ADFI). The feed-to- gain ratio (F / G) was calculated based on ADG and ADFI as follows: ADG = (Final Weight - Initial Weight) I Number of Trial Days; ADFI = Feed Consumption I (Number of Piglets per Group x Number of Trial Days); F / G = Average Daily Feed Intake I Average Daily Gain. Evaluation of diarrhea in piglets from day 0 to 28: The fecal consistency of each piglet was observed and recorded daily during the trial period to calculate the diarrhea rate (DI), calculated as follows: Diarrhea Rate (%) = (Number of Diarrhea Episodes per Piglet During the Trial) / (Number of Piglets per Group x Number of Trial Days) x 100%.

[0123] Table 3a - Feed composition

[0124] Table 3c EFA formulated composition

[0125] Table 3d Results a~bDifferent letters of superscript in the same line indicated significant differences among different groups (P < 0.05).

[0126] The piglet weight results at different time points in Table 3d showed that both ZnO and the composition according to the invention, compared with CON, had a significantly higher average daily gain (ADG) and a significantly lower diarrhea rate on d 0-14 (P < 0.05). The composition according to the invention also exhibited a significant reduction in feed-to-gain ratio (F / G) (P < 0.05) in any administration regime tested. On d 15-28, compared with CON, EFA_500, EFA_750 and EFA_1000 significantly increased ADG and reduced diarrhea rate (P < 0.05), alleviating the post-weaning diarrhea.

[0127] It has been clearly shown that the performance provided with the animal feed additive composition in accordance with the present invention, even if administered at a regime of 0.5 kg / ton provided the same if not better results on the piglets than ZnO when administered at a level four time higher, of 2 kg / ton. This not only shows that the composition according to the invention is not a mere alternative to ZnO but instead brings improvements in terms of amount of feed additive to be used.

Claims

CLAIMS1 . An animal feed additive composition comprising: a) 45-65 % by weight, with respect to the total weight of the a)+b), of a butyric acid glycerol ester, said butyric acid glycerol ester comprising at least 75 % by weight of tributyrin, and b) 35-55% by weight, with respect to the total weight of the a)+b), of a valeric acid glycerol ester, said valeric acid glycerol ester comprising at least 30 % by weight of monovalerin.

2. The animal feed additive composition according to claim 1 , wherein said butyric acid glycerol ester comprises at least 80 % by weight of tributyrin.

3. The animal feed additive composition according to claim 1 or 2, wherein said valeric acid glycerol ester comprises at least 40 % by weight of monovalerin.

4. The animal feed additive composition according to any of the claims 1 -3, wherein the animal feed additive composition further comprises, with respect to the total weight of a)+b), 1 -15 % by weight of an essential oil.

5. The animal feed additive composition according to claim 4 wherein the essential oil is selected from the group consisting of: cinnamic aldehyde, carvacrol, thyme oil, inulin, garlic oil, betanine, quilliaja saponin, D-limonene, orange oil and combinations thereof.

6. The animal feed additive composition according to any one of the claims 1 -5, wherein said animal feed additive composition comprises an acid scavenger.

7. The animal feed additive composition according to any of the claims 1 -6, wherein said animal feed additive composition comprises, with respect to the total weight of a)+b), less than 4 % by weight of a free short chain fatty acid selected from the group consisting of valeric acid and butyric acid.

8. The animal feed additive composition according to any one of the claims 1 -7, wherein said animal feed additive composition comprises with respect to the total weight of a)+b), less than 4 % by weight of glycerol.

9. The animal feed additive composition according to any of the claims 1 - 8, wherein the composition further comprises a buffering agent.

10. A granular feed additive for animal nutrition comprising the animal feed additive composition according to any of the claims 1 - 9, wherein said animal feed additive composition is loaded on a granular carrier.1 1 . The granular feed additive for animal nutrition according to claim 10, wherein said granular carrier is silica.

12. An animal feed additive composition according to any claim from 1 to 9 or a granular feed additive for animal nutrition according to claim 10 or 1 1 , for use in promoting the gastro-intestinal functionality in an animal.

13. The animal feed additive composition or the granular feed additive for animal nutrition for use according to claim 12, wherein said use entails at least one beneficial effect in said animal, said beneficial effect being selected from the group consisting of:- promotion of the gastro intestinal growth,- improvement of the feed conversion ratio,- improvement of the growth performance,- improvement of the development of a apposite microbiota in the intestinal tract- reduction of gastrointestinal microbial dysbiosis;- reduction of the growth of harmful microbiota, and- stimulation of growth of beneficial microbiota.

14. The animal feed additive composition or the granular feed additive for animal nutrition for use according to claim 13, wherein said harmful microbiota comprises at least one microorganism belonging to a genus selected from the group consisting of: Prevotella, Sutterella, Campylobacter, Fusobacteriaceae, and Enterobacteriaceae.

15. The animal feed additive composition or the granular feed additive for animal nutrition for use according to claim 13, wherein said beneficial microbiota comprises at least one microorganism belonging to a genus selected from the group consisting of: Prevotellaceae, Lahnospiraceae, Lachnospiraceae, Ruminococcaceae, Lactobacillaceae, and Bifidobacterium.

16. The animal feed additive composition or the granular feed additive for animal nutrition for use according to any of the claims 12 - 15, wherein said animal is a mammal.

17. The animal feed additive composition or the granular feed additive for animal nutrition for use according to claim 16, wherein the mammal is a monogastric mammal.

18. The animal feed additive composition or the granular feed additive for animal nutrition for use according to claim 17, wherein the monogastric animal is a pig.

19. The animal feed additive composition or the granular feed additive for animal nutrition for use according to claim 18, wherein the pig is a weaned piglet or a nursery Pig-20. The animal feed additive composition or the granular feed additive for animal nutrition for use according to claim 19, wherein said weaned piglet or nursery pig is in the pre-grower phase.21 . The animal feed additive composition or the granular feed additive for animal nutrition for use according to any of the claims 12-20, wherein said animal feed additive composition is administered to said animal in an amount of 0.25 - 1.5 gram per kilogram of feed.

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