Composition comprising a protein hydrolysate and a microalgae extract and use thereof as an agricultural biostimulant

Abstract

The present invention relates to compositions comprising a protein hydrolysate and a microalgae extract. The protein hydrolysate which is included in the compositions of the invention originates from the hydrolysis of animal proteins, in particular from the hydrolysis of pig farming coproducts. The present invention also relates to the method for preparing these compositions, and also to the use of these compositions as agricultural biostimulants.

Description

[0001]Composition comprising a protein hydrolyzate and a microalgae extract and its use as an agricultural biostimulant. FIELD OF THE INVENTION The present invention relates to the agricultural field. It relates to compositions comprising a protein hydrosol and a microalgae extract. The protein hydrolyzate which is included in the compositions of the invention comes from the hydrolysis of animal proteins. The present invention also relates to the process for preparing these compositions, as well as to the use of these compositions as agricultural biostimulants. STATE OF THE ART For many years, the application of chemical fertilizers has been a widely used agricultural practice in the development of intensive agriculture (Oui, L. et al., 2020; González, M. et al., 2015).However, the continued use and misuse of these synthetic fertilizers have caused many negative effects related to the depletion of natural resources as well as the generation of greenhouse gases, water eutrophication, soil salinization, and food safety issues and quality deterioration (González, M. et al., 2015; Ashour, M. et al., 2021; Hassan, SM. et al., 2021). These chemicals also increase plant susceptibility to pathogens, altering the soil microbiome and influencing plant health, which poses a significant threat to consumers (Colla, G. and Rouphael, Y., 2015). For this reason, sustainability in agricultural production is necessary both to meet consumer demand for healthy products and to try to eliminate or reduce the aforementioned problems (González, M. et al., 2015; Hassan, SM. et al., 2021; Colla, G. and Rouphael, Y., 2015; Colla, G. et al., 2014). Currently, the use of biostimulants is widespread in sustainable agriculture as they represent an alternative to chemical fertilizers (Ávila-Pozo P. et al., 2022). Biostimulants are natural preparations that have the potential to reduce the need for fertilizers with an increase in plant growth, even in cases of water and abiotic stress. Current biostimulants are of different types, namely microbial or non-microbial. They include active substances such as humic and fulvic acids, protein hydrolysates, seaweed extracts, beneficial fungi, bacteria, and algae. They can be single- or multi-component formulations, although it can provide a positive action of different components. Biostimulants can be applied by foliar or soil application. They can be hydrolysis products, fermented, or extracted.A number of biostimulants consisting of protein hydrolysates have been used (Colla, G. et al., 2014). These substances, which are generally obtained by enzymatic hydrolysis processes, are generally made up of low molecular weight peptides, amino acids, polysaccharides, etc., used in a wide variety of crops such as cereals, fruits and vegetables and have been shown to have a large number of positive effects on these crops, such as increased productivity and better quality (Ertani, A. et al., 2014; Tejada, M. et al., 2016; Tejada, M. et al., 2018; Rouphael Y. and Colla G., 2018). According to Searchinger T., 2013 and Kapoore RV et al., 2021, the use of these biostimulants in agriculture has two objectives, namely to increase the supply and quality of food for the world population and to reduce the negative effect of agriculture on the environment and human health.To find solutions to the challenge of improving the sustainability of agricultural systems by reducing the use of synthetic inorganic fertilizers, there is therefore still a real need to develop new compositions with a biostimulant effect. In particular, compositions that exhibit a biostimulant effect both under normal conditions and under water stress would be of enormous scientific and agricultural interest. DISCLOSURE OF THE INVENTION The present invention makes it possible to meet the needs set out above. The present inventors have in fact developed a new composition obtained from a protein hydrolyzate combined with a microalgae extract. The inventors have notably shown that such a composition exhibits a significant, even synergistic, biostimulant effect, making it possible to increase the growth and yield (in grains, fruits, etc.) of various plants useful in plant production.This new composition is all the more interesting since this advantageous effect is obtained both under "normal" crop irrigation conditions, but also under water stress conditions (lack of water or drought). The inventors have indeed succeeded in obtaining a biostimulant whose amino acid composition of interest has a particularly advantageous peptide signature, and in particular concerning its tryptophan content which has a role as an auxiliary hormonal precursor in plants. In addition, some of the components of this new composition with a biostimulant effect may in particular come from industrial co-products such as co-products from animal breeding, in particular pig farming. The production of this biostimulant therefore constitutes an alternative of great environmental interest since the recovery of these co-products leads to their elimination, and therefore a reduction in their environmental impact.Similarly, the energy of industrial installations can be used to meet the temperature requirements of microalgae cultivation. Thus, the production of microalgae from which the extract contained in this new composition is derived can in particular make it possible to reduce the energy bills of industrial production sites. It is in this context that the present invention provides a new composition comprising a protein hydrolyzate of animal origin, preferably derived from the hydrolysis of by-products of pig farming, and a microalgae extract. Preferably, this composition comprises a pig bristle protein hydrolyzate and / or a pig lung mucus protein hydrolyzate. Preferably, this composition comprises a spirulina extract, and in particular a phycocyanin extract. Advantageously, the composition according to the invention contains the amounts of amino acids as described in Table 2.Preferably, the composition of the invention contains amino acids whose molecular weight distribution is 3-4% between 1000 Da and 3000 Da, 2.5-3% between 800 Da and 1000 Da, 68-72% between 204 Da and 800 Da and 23-25% less than 204 Da. Preferably, the composition of the invention comprises 1-15% hydrolyzate and 1-5% microalgae extract, and optionally a carrier or vehicle acceptable in the agricultural field. The present invention also relates to a process for preparing the above-mentioned composition comprising: - providing at least one protein hydrolyzate of animal origin, preferably derived from the hydrolysis of by-products of pig farming, - providing a microalgae extract, and - mixtures thereof. The present invention also relates to the use of such a composition as an agricultural biostimulant, and in particular under normal irrigation conditions or under water stress conditions.The composition of the invention is preferably used as a biostimulant for large-scale crops, market gardening, viticulture, forestry, arboriculture and horticulture. Finally, the present invention also relates to a kit for the preparation of a biostimulant which comprises, on the one hand, at least one protein hydrolyzate of animal origin, in particular derived from the hydrolysis of by-products of pig farming and a microalgae extract or a mixture thereof, on the other hand at least one support or vehicle acceptable in the agricultural field, and possibly instructions for use. DESCRIPTION OF THE FIGURES Other characteristics, aims and advantages of the invention will emerge from the description which follows, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which: [Fig.1] Figure 1 shows, in the form of histograms, the results of grain yield measurement in rapeseed (g / plant), grown without treatment (MO) or treated with 2L / ha of microalgae extract (AEC 2L), 6L / ha of microalgae extract (AEC 6L), with 2L / ha of protein hydrolysate of pork co-products (CP 2L), 6L / ha of protein hydrolysate of pork co-products (CP 6L) or with the mixture of 6L / ha of microalgae extract and 6L / ha of protein hydrolysate of pork co-products (MA). [Fig.2] Figure 2 shows, in the form of histograms, the results of measuring the quantity of total dry matter in rapeseed, grown under normal irrigation conditions, without treatment (MO) or treated with 2L / ha of microalgae extract (AEC 2L), 6L / ha of microalgae extract (AEC 6L), with 2L / ha of protein hydrolysate of pork co-products (CP 2L), 6L / ha of protein hydrolysate of pork co-products (CP 6L) or with the mixture of 6L / ha of microalgae extract and 6L / ha of protein hydrolysate of pork co-products (MA). [Fig.3] Figure 3 shows, in the form of histograms, the results of measuring the quantity of total dry matter in rapeseed, grown under drought conditions, without treatment (MO) or treated with 2L / ha of microalgae extract (AEC 2L), 6L / ha of microalgae extract (AEC 6L), with 2L / ha of protein hydrolysate of pork co-products (CP 2L), 6L / ha of protein hydrolysate of pork co-products (CP 6L) or with the mixture of 6L / ha of microalgae extract and 6L / ha of protein hydrolysate of pork co-products (MA). [Fig. 4] Figure 4 represents, in the form of histograms, the effect of a composition according to the invention applied at several doses (BST 1.5L / ha, BST 3 L / Ha, BST 6L / Ha), to the tomato crop, in comparison with that of a reference product (IDROGENA ENERGY; 3L / Ha) or with an untreated sample (TNT), during three successive harvests. [Fig.5] Figure 5 represents, in the form of histograms, the effect of a composition according to the invention applied at several doses (BST 1.5L / ha, BST 3 L / Ha, BST 6L / Ha), on the tomato production yield, in comparison with that of a reference product (IDROGENA ENERGY; 3L / Ha), during three successive harvests. [Fig. 6] Figure 6 represents, in the form of histograms, the effect of a composition according to the invention applied at several doses (BST 1.5L / ha, BST 3 L / Ha, BST 6L / Ha), on the number of fruits harvested (tomatoes), in comparison with that of a reference product (IDROGENA ENERGY; 3L / Ha) or with an untreated sample (TNT), during three successive harvests. [Fig. 7] Figure 7 represents, in the form of histograms, the effect of a composition according to the invention applied at several doses (BST 1.5L / ha, BST 3 L / Ha, BST 6L / Ha), on the quality of the harvest evaluated by measuring the sugar content of the harvested fruits (tomatoes) according to the BRIX scale, in comparison with that of a reference product (TRAINER EDEN STRIM; 3L / Ha) or with an untreated sample (TNT). [Fig. 8] Figure 8 represents, in the form of histograms, the effect of a composition according to the invention applied at several doses (BST 1.5L / ha, BST 3 L / Ha, BST 6L / Ha), on the physiology of the plant evaluated by measuring the chlorophyll content of tomato plants, in comparison with that of a reference product (GOACTIV; 100ml diluted in 100 L of water applied per hectare) or with an untreated sample (TNT). [Fig. 9] Figure 9 represents, in the form of histograms, the effect of a composition according to the invention applied at several doses (BST 1.5L / ha, BST 3 L / Ha, BST 6L / Ha), on the physiology of the plant evaluated by measuring the induction of flowering on tomato plants, in comparison with that of a reference product (GOACTIV; 100ml diluted in 100 L of water applied per hectare) or with an untreated sample (TNT), during two successive harvests. [Fig. 10] Figure 10 represents, in the form of histograms, the effect of a composition according to the invention applied at 6L / Ha, on the physiology of the vine evaluated by measuring the percentage of flowers, in comparison with that of a reference product (VIVAFLOR; 2L / ha) or with an untreated sample (TNT). [Fig. 11] Figure 11 represents, in the form of histograms, the effect of a composition according to the invention applied at 6L / Ha, on the production of the vine evaluated by measuring the yield in tonnes of grapes harvested per hectare, in comparison with that of a reference product (VIVAFLOR; 2L / ha) or with an untreated sample (TNT). [Fig.12] Figure 12 represents, in the form of histograms, the effect of a composition according to the invention applied at 6L / Ha, on the production of the vine evaluated by measuring the number of grape bunches harvested per plot (47 m. 2), in comparison with that of a reference product (VIVAFLOR; 2L / ha) or with an untreated sample (TNT). [Fig. 13] Figure 13 represents, in the form of histograms, the effect of a composition according to the invention applied at 6L / Ha, on the quality of the vine harvest evaluated by measuring malic acid in the harvested grapes, in comparison with that of a reference product (VIVAFLOR; 2L / ha) or with an untreated sample (TNT). [Fig. 14] Figure 14 represents, in the form of histograms, the effect of a composition according to the invention applied at 6L / Ha, on the quality of the vine harvest evaluated by measuring tartaric acid in the harvested grapes, in comparison with that of a reference product (VIVAFLOR; 2L / ha) or with an untreated sample (TNT). [Fig. 15] Figure 15 represents, in the form of histograms, the effect of a composition according to the invention applied at 6L / Ha,on the quality of the vine harvest evaluated by measuring the alcohol content in the harvested grapes, in comparison with that of a reference product (VIVAFLOR; 2L / ha) or with an untreated sample (TNT). [Fig. 16] Figure 16 represents, in the form of histograms, the effect of a composition according to the invention applied at 6L / Ha, on the quality of the vine harvest evaluated by measuring the potassium in the harvested grapes, in comparison with that of a reference product (VIVAFLOR; 2L / ha) or with an untreated sample (TNT). [Fig. 17] Figure 17 represents, in the form of histograms, the effect of a composition according to the invention applied at 6L / Ha, on the quality of the vine harvest evaluated by measuring assimilable nitrogen, in comparison with that of a reference product (VIVAFLOR; 2L / ha) or with an untreated sample (TNT). [Fig. 18] Figure 18 represents, in the form of histograms, the effect of a composition according to the invention applied at 6L / Ha,on apple production evaluated by measuring the quantity of apples harvested from two trees (Kg / 100 Kg fruits), in comparison with that of a reference product (PHYLGREEN; 300 ml / 100L) or with an untreated sample (TNT). DETAILED DESCRIPTION OF THE INVENTION Definitions By "livestock co-products" also called "livestock by-products", we mean a co-product that is created during a livestock process and at the same time as the main product of livestock. In the case of co-products of animal farming, these are the parts of the animal that are not intended for human consumption. For example, by-products of pig farming are testes, bristles (i.e. hair), lobes, spleen, heart, lungs, lung mucus, trachea, blood and cruor (i.e. the solid part of the blood). By "protein hydrolysate" or "protein hydrolysate" or "peptone",means a mixture of amino acids and peptides derived from proteins. Protein hydrolysis corresponds to the cleavage of the peptide bonds between the amino acids resulting in a protein hydrolysate. Protein hydrolysates are mainly produced by enzymatic and / or chemical hydrolysis (with strong acids or alkalis) of animal or vegetable proteins. In the context of the present invention, it is an animal protein hydrolysate, and preferably an animal protein hydrolysate except a hydrolysate derived from chicken feathers. By "components" or "constituents" is meant the active substances of the composition according to the invention, that is to say those which give it its biostimulating effect on plant production. In the present application, the value ranges are indicated in abbreviated form,in order to avoid having to set out in detail and describe each of the values ​​in the range. Any suitable value within the interval may be chosen, as appropriate, as the upper value, lower value, or endpoint of the interval. For example, a range of 0.1-1.0 represents the terminal values ​​of 0.1 and 1.0, as well as the intermediate values ​​of 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and all intermediate ranges within the range 0.1-1.0, such as 0.2-0.5, 0.2-0.8, 0.7-1.0, etc. The words "includes," "include," and "comprising" shall be construed inclusively. Similarly, the terms "include,""including" and "or" shall all be interpreted as inclusive. All such terms, however, shall be construed as encompassing exclusive embodiments which may also be designated by words such as "consist of". "Proteins" are macromolecules found in all living cells. They consist primarily of carbon (C), hydrogen (H), oxygen (O), and nitrogen (N). They perform a multitude of biological functions and are composed of peptides, which are themselves composed of amino acids. The term "amino acid" refers to a molecule containing both an amine group and a carboxyl group. In certain embodiments, the amino acids are α-, β-, γ-, or δ-amino acids, including their stereoisomers and racemates. By "biostimulant",we mean both the biostimulant action but also the composition which has this action in the agricultural field. The biostimulant action provides a positive effect on crop performance (physiology, production, yield, harvest qualities, etc.), and more particularly in conditions of environmental stress. Indeed, the biostimulant action according to the invention can in particular be exerted through an improvement in photosynthesis activity, an increase in leaf nitrogen content, in proteins of lipid metabolism and photosynthesis, in lipids of chloroplast membranes, in phytohormones, but also through an improvement in plant defense mechanisms and in particular the response to stress. Biostimulants are fertilizers which stimulate the nutrition process of plants independently of the nutrients they contain,for the sole purpose of improving one or more of the following characteristics of plants or their rhizosphere: nutrient use efficiency, abiotic stress tolerance, quality characteristics, and the availability of nutrients confined in the soil and rhizosphere (European Commission definition from European Regulation 2019 / 1009 published in the Official Journal in June 2019 and which will be applicable in July 2022). By "agricultural" or "agricultural field" is meant everything related to plant production, and in particular land work and plant production. Thus, the agricultural field / field / specialty / activity includes, consists essentially of, consists of or is a field / field / specialty / activity that falls within plant production (i.e. the field devoted to or relating to land work and plant production). The agricultural composition includes, consists essentially of,consists of or is therefore a composition suitable for and / or a composition for working the land and producing plants. Agricultural use includes, consists essentially of, consists of or is therefore a use suitable for and / or in working the land and producing plants. By "plant production" or "plant production" is meant everything related to large-scale crops, market gardening, viticulture, forestry, arboriculture and horticulture. In this context, "large-scale crops" include cereal crops (wheat, barley, corn, oats, etc.), oilseed crops (rapeseed, sunflower) and protein crops (fava beans and peas),beet cultivation (sugar and fodder) and potato cultivation. “Market gardening” concerns the production of fresh vegetables grown in greenhouses or in open fields. “Arboriculture” concerns the cultivation of perennial fruit trees and the cultivation of small shrub-type fruits. “Horticulture” can cover all specialized agricultural orientations: market gardening, arboriculture, floriculture and nursery. However, the term “horticulture” is restricted here to floriculture (or floral horticulture), ornamental horticulture and nursery activities. “Vehicle” or “support” means any substance of a composition other than the active component(s) thereof. The addition of a carrier to a composition is intended to impart stability, consistency, shape, dissolution property(ies), targeting property(ies), preservation property(ies), half-life, bioavailability, taste,a color, one or more aesthetic properties and / or a given texture, or other particular physical, chemical, biological or taste characteristics. A support is therefore defined more by its use than by a particular chemical composition, said use resulting in particular from its physicochemical properties which make it suitable for fulfilling its role as a support. The support may in particular be a stabilizing agent, a preservative, an antioxidant, a texturing agent or texture agent, a binder, an emulsifier, a colorant, a pigment, a corrosion inhibitor, a polymerization inhibitor, an anti-caking agent, a surfactant (which may also be called an emulsifier, wetting product, dispersant, emulsifier), an anti-foaming agent, an anti-leaching agent, a thickener, a solubilizer, a humectant, a desiccant, an antiozonant agent, an anti-UV agent (photoprotector, UV absorber), a thermal stabilizer, an antifreeze agent, a flame retardant,an adhesion promoter, a solvent, a diluent, an antistatic agent, a buffer additive, an olfactory tracer, an agent combining any of these characteristics. The support preferably has no negative interaction, particularly chemical, with the components of the composition containing them, i.e. the support does not induce any reduction in the desired activity / action / effect of these active substances, either before or after application / administration to the plants to be treated. The support may also be neutral with respect to the components, i.e. it does not affect in any way the activity / action / effect of these components. The support is preferably non-toxic (in particular for the plants to be treated, in particular cereal crops, market garden crops, vines, fruit trees. The support is preferably essentially of natural origin. The support is preferably essentially biodegradable. More preferably,the support is essentially bio-sourced. Particularly preferably, the support is essentially bio-sourced and essentially biodegradable. By "support acceptable in the agricultural field" is meant a support suitable for agricultural use, and in particular for plant production. In particular, it is meant a support capable of being incorporated into a composition for agricultural use. Advantageously, the agriculturally acceptable support does not induce any reduction in the desired phytosanitary activity / action / effect of the components of the composition of the invention. The agriculturally acceptable support is preferably non-toxic (in particular for the plants to be treated, in particular cereal crops, market garden crops, vines,fruit trees. The support is preferably of natural origin. The support is preferably essentially biodegradable. The support is more preferably essentially biosourced. The support is preferably biodegradable and / or biosourced. By "sprayable solution" is meant a solution that can be projected in fine liquid droplets or in powder form. Advantageously, the sprayable solution is in suspension, emulsion or solution in a gaseous medium, preferably in an inert gas. Advantageously, the sprayable solution is presented in the form of a sprayer, vaporizer, aerosol, or spray. By "spraying" is meant the projection of a solution in fine liquid droplets, in aerosol form, in vapor form, or in powder form, onto an object, preferably a crop, in particular cereal crops, market garden crops, vines, fruit trees. Description of the invention According to a first aspect,the present invention relates to a composition comprising a protein hydrolyzate of animal origin, preferably derived from the hydrolysis of by-products of pig farming, and a microalgae extract. The protein hydrolyzate can be obtained by any hydrolysis process well known to those skilled in the art, and in particular by chemical hydrolysis or by enzymatic hydrolysis. For example, the protein hydrolyzate of the composition according to the invention can correspond to CAS number 100085-61-8. The composition according to the invention can comprise, in addition to the microalgae extract, two animal protein hydrolysates. They can be obtained by the same type of hydrolysis process or by different hydrolysis processes, and preferably they are obtained by different hydrolysis processes. Advantageously, when the composition comprises two animal protein hydrolysates, one is obtained by chemical hydrolysis and the other by enzymatic hydrolysis. Thus,a particularly preferred composition comprises on the one hand a chemical hydrolyzate and an enzymatic hydrolyzate of animal proteins and on the other hand an aqueous extract of microalgae. Preferably, the composition according to the invention comprises, in addition to the microalgae extract, a hydrolyzate of pig bristle proteins and / or a hydrolyzate of pig lung mucus proteins. More preferably, it comprises a hydrolyzate of pig bristle proteins and a hydrolyzate of pig lung mucus proteins. A particularly preferred composition according to the invention comprises a protein hydrolyzate derived from the chemical hydrolysis of pig bristles and a protein hydrolyzate derived from the enzymatic hydrolysis of pig lung mucus. Preferably, the microalgae extract contained in the composition according to the invention is a spirulina extract, and in particular a phycocyanin extract. For example,the microalgae extract of the composition according to the invention may correspond to CAS number 20298-86-6. The microalgae extract contained in the composition according to the invention ideally has significant antioxidant activity. This activity can be measured by any method known in the field by the person skilled in the art, and in particular by spectrophotometry, in particular at 620 nm and 652 nm. Preferably, the microalgae extract has an antioxidant activity of at least 70 measured according to the ORAC method (notably described by Agregan R. et al., 2018) and more preferably an antioxidant activity in a range from 70 to 100 according to the ORAC method, or equivalent if this activity is measured by another method. The antioxidant activity of the microalgae extract contained in the composition according to the invention can in particular range from 60 to 90, and advantageously, it has an antioxidant activity ranging from 73 to 76, preferably from 74 to 75,of approximately 75 according to the ORAC measurement method, and in particular of 74.5. Preferably, the constituents of the composition of the invention contain the quantities of amino acids which are indicated in the following table 1. [Table 1] Amino acids Protein hydrolyzate Microalgae extract (g / 100g protein) (mg / 100g extract)glutamic acid10-20, preferably 12-16 20-32, preferably 25-30glycine 5-10, preferably 7-9 17-25, preferably 20-23aspartic acid6-12, preferably 8-10 20-32, preferably 20-25leucine 6-12, preferably 8-10 20-32, preferably 25-30alanine 3-10, preferably 4-7 20-30, preferably 20-25 lysine 3-10, preferably 4-8 3-10, preferably 4-7 proline 3-10, preferably 4-7 8-15, preferably 9-12 valine 3-10, preferably 4-7 6-15, preferably 8-10 arginine 4-12, preferably 5-10 20-32, preferably 25-28 phenylalanine 2-6, preferably 4-7 17-25, preferably 20-24 serine 3-10, preferably 4-9 14-20,preferably 15-18 threonine 2-6, preferably 3-5 12-18, preferably 14-17 histidine 1-4, preferably 1.5-3 3-10, preferably 4-6 tyrosine 2-6, preferably 3-5 25-35, preferably 27-32 isoleucine 2-6, preferably 3-5 20-32, preferably 25-28 cysteine ​​1-8, preferably 1.5-6.5 2-10, preferably 3-6 methionine 0.5-4, preferably 1-3 9-15, preferably 11-14 tryptophan 0-3, preferably 0.5-2.5 1-6, preferably 2-4 The composition according to the present invention has a peptide signature of great interest due to the presence of a combination of acids amino acids leading to specific effects that play a very important role in the metabolism or the constitution of proteins of particular interest to the plant. In particular, we can note the significant presence of alanine, aspartic acid, glutamic acid, involved in improving the assimilation of nutrients, but also leucine, cysteine,valine for improving energy production, or proline, and serine which are involved in signaling in the event of stress. Furthermore, it has been shown that, in apple trees, tryptophan and glycine, alone or in combination, significantly increase the height and diameter of the aerial part, the leaf area, the chlorophyll content, the percentage of fruits and the yield as well as the physical and chemical characteristics of the fruits, and also the mineral composition of the leaves (Mosa et al., 2021). Thus, preferably, the composition according to the present invention advantageously contains the quantities of amino acids which are mentioned in the following table 2. [Table 2] Amino Acids Composition according to the invention (mg / 100g of composition) TRYPTOPHAN 8-20, preferably 10-15 Aspartic acid 250-300, preferably 270-290 Threonine 120-150, preferably 125-145 Serine 160-200,preferably 170-190 Glutamic acid 500-700, preferably 525-650 Proline 150-200, preferably 165-195 Glycine 230-300, preferably 240-280 Alanine 180-240, preferably 200-230 Valine 160-230, preferably 185-215 Cysteine ​​30-80, preferably 40-70 Methionine 20-60, preferably 30-50 Isoleucine 100-180, preferably 130-160 Leucine 200-320, preferably 230-300 Tyrosine 60-140, preferably 10-80-120 Phenylalanine 100-140, preferably 115-135 Lysine 10-50, preferably 15-35 Histidine 40-80, preferably 45-65 Arginine 230-300, preferably 240-290 Preferably, the composition according to the invention contains amino acids whose molecular weight distribution is 3-4% between 1000 Da and 3000 Da, 2.5-3% between 800 Da and 1000 Da, 68-72% between 204 Da and 800 Da and 23-30% below 204 Da. More preferably, it contains amino acids whose molecular weight distribution is 3.2-3,4% between 1000 Da and 3000 Da, 2.5-2.8% between 800 Da and 1000 Da, 69-70% between 204 Da and 800 Da and 24-25% less than 204 Da. According to a particularly preferred embodiment of the present invention, the composition comprises 1-15% hydrolyzate, preferably 10-15%, and most particularly about 13%, and 1-5% microalgae extract, preferably 2-4%, in particular spirulina extract, and preferably a spirulina extract containing 1.5 to 2g / L of phycocyanin, and optionally a support or vehicle acceptable in the agricultural field. The composition according to the invention may be in a liquid form or in a solid form (such as powder, granules, tablets). Preferably, the composition is in a liquid form, preferably in the form of an aqueous solution. According to a second aspect, the present invention relates to a process for preparing the composition according to the invention as described above,characterized in that it comprises: - the provision of at least one protein hydrolyzate of animal origin, in particular from the hydrolysis of by-products of pig farming, - the provision of a microalgae extract, and - their mixtures. The animal protein hydrolyzate can be obtained according to any hydrolysis method well known in the field by the person skilled in the art, in particular by enzymatic hydrolysis, for example in the presence of one or more proteases (pepsin, papain, pancreatin, subtilisin, etc.), or by chemical hydrolysis, for example with one or more strong or alkaline acids. The preparation process according to the invention may in particular comprise the provision of a protein hydrolyzate corresponding to CAS number 100085-61-8. Preferably,The preparation method comprises providing a chemical hydrolyzate and an enzymatic hydrolyzate. The chemical hydrolyzate is preferably derived from pig bristles. The enzymatic hydrolyzate is preferably derived from pig lung mucus. The microalgae extract is preferably an aqueous extract, in particular an aqueous extract of spirulina. The method may in particular comprise providing a microalgae extract corresponding to CAS number 20298-86-6. Advantageously, the method for preparing the composition according to the invention comprises: - providing a chemical hydrolyzate of pig bristles, preferably obtained by acid thermal hydrolysis, and / or providing an enzymatic hydrolyzate of pig lung mucus, preferably obtained using one or more proteases - providing a spirulina extract, preferably an aqueous extract, and in particular an aqueous extract of phycocyanin; and - mixtures thereof. Preferably,the method for preparing the composition of the invention comprises the preparation of a spirulina extract obtained by extraction without any solvent other than water, in particular from dry spirulina. Optionally, this preparation step is followed by a filtration step. The spirulina extract can also be prepared in advance and then frozen until use. According to a third aspect, the present invention relates to the use of the composition described above as an agricultural biostimulant. The composition according to the invention can be used as an agricultural biostimulant under normal irrigation conditions or under water stress conditions. The composition of the invention can be used as a biostimulant on any type of plant crop. Preferably, it is used for field crops, market gardening, viticulture, forestry, arboriculture and horticulture. More preferably,it is used as a biostimulant on cereal crops, market garden crops, vines, fruit trees. Advantageously, the composition of the invention is used as a biostimulant for the cultivation of rapeseed, tomatoes, vines and apple trees. The biostimulant action of the composition according to the present invention can be demonstrated according to conventional methods, well known to those skilled in the art, and which will be chosen according to the relevant parameters to be taken into account for this purpose. They will depend on the type of crop concerned, for example the measurement of the production yield based for example on the number of grains, fruits, the measurement of growth (leaf or root extension, induction of flowering), the assessment of the quality of the harvests (fruits, grains). The composition in fact has a biostimulant action whatever the form in which it is presented. Thus,the composition of the invention can be applied to crops in liquid form, or in solid form, and in particular in powder form. When the composition is applied in liquid form, it can be presented in liquid form directly ready for use, or to be diluted from a concentrated form. When the composition is applied in liquid form, it can also be presented in solid form and can then be diluted / dissolved / put into solution / solubilized in a suitable solvent before use (for example extemporaneously, or for short, medium or long-term storage before use). According to one embodiment, the composition is a liquid composition, preferably in the form of an aqueous solution, preferably in the form of a sprayable aqueous solution,more preferably in the form of an aerosol. The liquid composition may in particular be in a concentrated form (which may for example be diluted before use, for example 20 times concentrated, or 15 times, 10 times, 8 times, 5 times, 4 times, 3 times or even 2 times concentrated) or in a ready-to-use form. According to one embodiment, the composition is a liquid composition obtained by diluting (and / or dissolving and / or dissolving and / or solubilizing) the composition in a solid form in an appropriate solvent, preferably according to an appropriate dilution factor, in particular so as to obtain the amino acid contents as described in Table 2. The solvents suitable for diluting / dissolving / dissolving / solubilizing the concentrated liquid composition and / or the solid composition may for example be chosen from aqueous solvents,and preferably water. A person skilled in the art knows how to determine the appropriate dilution factors in order to obtain a liquid composition having amino acid contents as described in Table 2, from a concentrated liquid composition or a solid composition. In the context of its use as a biostimulant, the composition of the invention can be applied by deposit, in particular by dripping and / or spraying and / or vaporization and / or projection, for example directly onto the growing soil or onto the plants, in particular via foliar and / or root application. Thus, the composition can be deposited at the foot of the crops and / or sprayed and / or vaporized and / or projected onto the crops. The method of application will also be adapted to the type of crops. According to a preferred embodiment,the use is characterized in that the composition is applied to the crops by spraying and / or vaporization and / or projection. The quantity and number of applications and their frequency will be adapted according to the type of crop concerned. For example, the composition of the invention can be used in quantities ranging from 1 to 10L / ha, ranging from 1.5 to 6L / ha, or even ranging from 3 to 5L / ha, in one or more applications more or less spaced out over time. Furthermore, the use of the composition of the invention will also be adapted to the stages of development or growth of the crop concerned, for example the use is characterized in that the composition is applied to the crops before and / or after harvesting said crops. The person skilled in the art will be able to adapt all the criteria of use, which include the method of application, the number,the frequency and the stage(s) of development or growth of the crop concerned. In the context of its use, the composition of the invention may also be integrated into a more complex formulation, in particular a fertilizer, a phytosanitary product or any other composition useful for plant production. Preferably, the composition of the invention is integrated into a fertilizer composition. According to yet another aspect, the present invention relates to a kit for the preparation of a biostimulant, said kit comprising: - either at least one protein hydrolyzate of animal origin, preferably derived from the hydrolysis of by-products of pig farming and a microalgae extract, or a mixture thereof, - at least one support or vehicle acceptable in the agricultural field, - possibly instructions for use. Preferably,the kit according to the invention comprises: - either a hydrolyzate of pig bristle proteins and / or a hydrolyzate of pig lung mucus proteins and a microalgae extract, preferably a spirulina extract, or a mixture thereof, - at least one support or vehicle acceptable in the agricultural field, - optionally instructions for use. Advantageously, the kit according to the invention comprises: - either a hydrolyzate of pig bristle proteins, a hydrolyzate of pig lung mucus proteins, and a microalgae extract, preferably a spirulina extract, or a mixture thereof, - at least one support or vehicle acceptable in the agricultural field, - optionally instructions for use. All the preferred embodiments described above concerning the composition of the invention, and its components,as well as the support or vehicle acceptable in the agricultural field apply mutatis mutandis to the kit of the invention. The present invention also relates to the use of a kit as defined above for stimulating the growth and / or production of crops, preferably field crops, market gardening, viticulture, forestry, arboriculture and horticulture. The present invention further relates to a method for stimulating the growth and / or production of crops, comprising the application of a composition as defined above; wherein the crops are preferably field crops, market gardening, viticulture, forestry, arboriculture and horticulture. The present invention also relates to a method for stimulating the growth and / or production of crops, comprising the following steps: a) preparing a composition as defined above,comprising for example the dilution of the concentrated composition as defined above with an appropriate solvent, and / or the implementation of the kit as defined above); and b) the application of the composition obtained in step a) to the crop concerned. Advantageously, the composition is applied extemporaneously to carry out step b). Likewise, all the preferred embodiments described above concerning the composition of the invention, and its components, the support or vehicle acceptable in the agricultural field as well as the kit, apply mutatis mutandis to these other aspects of the invention. EXAMPLES Example 1 – Composition according to the invention A protein hydrolyzate corresponding to CAS number 100085-61-8 was mixed with a microalgae extract corresponding to CAS number 20298-86-6 so as to obtain an example of a composition of the invention. The protein hydrolyzate and the microalgae extract were added one by one into a cleaned and dried tank,containing the desired amount of water under continuous stirring, so as to obtain a composition comprising 13% hydrolyzate associated with 3% microalgae extract. The temperature during this process was 15 – 35 °C. The mixture was then passed through a Dyno-Mill grinder until a particle size conforming to the request (corresponding to approximately 20 micrometers) was obtained, in a tank equipped with a turbine mixer. Characterization of a composition according to the invention The composition thus obtained contains the mixture of amino acids which is mentioned in Table 3 below. [Table 3] Amino Acids Composition according to the invention (mg / 100g of composition) TRYPTOPHAN 11.2 Aspartic acid 282.5 Threonine 137.5 Serine 187.5 Glutamic acid 555 Proline 182.5 Glycine 260 Alanine 210 Valine 205 Cysteine ​​50 Methionine 37.5 Isoleucine 145 leucine 260 Tyrosine 100 Phenylalanine 120 Lysine 20 Histidine 57,5 Arginine 270 The molecular weight (MW) distribution of the amino acids present in the composition of the invention is summarized in Table 4 below. [Table 4] Distribution (%) MW in Dalton (Da) 3.3 3000>MW>1000 2.6 1000>MW>800 69.7 800>MW>204 24.4 204>MW Example 2 – Biostimulant effect The biostimulant effect of the composition prepared according to Example 1 was tested in field trials on different types of crops, in comparison with other biostimulants. Effect on rapeseed One of the crops that was targeted to evaluate the biostimulation effect is rapeseed (Brassica napus L.),which is an annual dicotyledonous herbaceous plant of the Brassicaceae family (formerly cruciferous). This plant is characterized by its yellow flowers, the processed seeds of which are used for animal and human food, but also for the production of biofuel. It can also be used as fodder for livestock. It is one of the main sources of edible vegetable oil in Europe since rapeseed contains around 45 to 50% oil and 18 to 22% protein. In France, the crop represents approximately 1.1 million hectares for an average yield of 35 q / ha, depending on annual climatic conditions. Rapeseed is the most widely cultivated oilseed in France and is the leading source of oil and protein-rich materials of French origin. The effect of the aqueous extract of phycocyanin from the microalgae spirulina (indicated AEC), protein hydrolysates from pork co-products (indicated CP),as well as the mixture of these components (indicated MA) was tested by spraying, and compared to that obtained on control plants (indicated MO). All plants (treated or not) received the same organic fertilization (organic fertilizer HUMIVAL NPK 5-5-2, supplier FERTIVAL, applied at a dose of 1 Ton / hectare. Grain yield under "normal" irrigation conditions, as well as the quantity of total dry matter of the plant, under "normal" conditions (indicated irrigated) or drought were measured on cultivated plants (treated or not) after applications made at the 5-9 leaf stage, then at the flower bud stage, then at flowering. The results are shown in Figures 1 to 3. They demonstrate that the components (microalgae extract or protein hydrolysates), as well as their mixture, have a positive effect on rapeseed grain yield (Figure 1). In addition,These results show that the components and their mixture have a positive effect on the total weight of the rapeseed plant, which demonstrates a favorable effect on plant growth, whether under normal irrigation conditions (sufficient water – Figure 2) or when the plants are subjected to water stress (Figure 3). Effect on tomatoes The biostimulant effect of the composition prepared according to Example 1 (BST) was tested, by spraying at several doses, during a field experiment on tomato crops (in Bulgaria, France and Spain). During these tests, different parameters were measured: production (fresh weight / plot, number of fruits), harvest quality (fruit sugar content), as well as plant physiology (chlorophyll content, flowering induction). The sugar content was measured according to the Brix scale which determines, in degrees Brix (°B or °Bx),the sucrose fraction in a liquid. One degree Brix is ​​equivalent to 1 gram of sucrose per 100 grams of solution. Chlorophyll content was measured using a SPAD 502 PLUS clamp-on CHLOROPHYLL-METER (supplied by SDEC France), which instantly measures the chlorophyll content of plant leaves on a scale of 0.0 to 99.9 (SPAD index). Flowering induction was measured by scoring the % of flowers on a scale of 0 to 100%, at the flowering stage corresponding to 10% flowers, and the second flowering at the stage of 50% flowers. The results of these tests are shown in Figures 4 to 9. These results highlight a statistically significant growth stimulation dose effect,and which stands out in effectiveness compared to crops treated with a fertilizer currently used (IDROGENA ENERGY). All of these results show that the application of a composition according to the invention to a market garden crop has a positive impact on its growth, its production and the quality of the fruits obtained. Effect on the vine The biostimulant effect of the composition prepared according to Example 1 (BST) was tested, by spraying at several doses, on the cultivation of the vine in France and the associated wine production, on an Auxerrois grape variety, Pedro Ximenez, merlot. During these tests,Different parameters were measured: plant physiology (flowering induction) and production (number of fruits and various harvest quality criteria). Flowering induction was measured by scoring the % of flowers on a scale of 0 to 100%. The malic acid content of the harvested grapes was measured by reflectometry using the reflectoquant® system marketed under ref. 1.16128.0001 by Merck Millipore. Malic acid (malate) is oxidized to oxalacetate by NAD under the catalytic action of malate dehydrogenase. The NADH thus produced reduces, in the presence of diaphorase, a tetrazolium salt to a red formazan which is measured by reflectometry. The tartaric acid content of the harvested grapes was measured using a special wine photometer for measuring tartaric acid, HI83748-02,according to the supplier's recommendations (HANNA Instruments). The alcohol content in the harvested grapes was measured with an OENO Calc mustimeter, according to the supplier's recommendations (Laboratoires Dujardin-Salleron), with which the probable alcohol obtained after complete fermentation is estimated; the calculations being established on the postulate that 16.83g of sugar per liter of must produce 1% volume of alcohol. The results obtained with the use of the composition at a dose of 6L / Ha are shown in Figures 10 to 15. Among the other criteria of the quality of the harvest, potassium and assimilable nitrogen were also measured to assess the effect of the composition of the invention (Figures 16 and 17). Indeed,Potassium acts in the migration and storage of sugars in fruits. Potassium is a factor for vine growth involved in photosynthesis and for yield with the neutralization of organic acids formed. It was measured by ICP AES (iCAP 6000, Thermo), after wet mineralization (analysis method accredited ISO 17025). Available nitrogen is also a factor for vine growth and associated with good vinification of musts. It was measured by the formalin method, also called the Sörensen method (MASNEUF and DUBOURDIEU, 1999). Effect on apple trees The biostimulant effect of the composition prepared according to Example 1 (BST) was also tested by spraying using the dose of 6L / Ha, on Spanish apple trees (FUJI, IDARED, PINK LADY) and the associated tree production,was evaluated. The results obtained are shown in Figure 18. All of these results demonstrate the advantageous biostimulant effect provided by the composition according to the invention on various crops, whether cereal, market garden, viticultural and arboricultural. REFERENCES Agregan R.et al., Medicines 2018, 5, 33; doi:10.3390 / medicines5020033 Ashour, M.; Hassan, SM; Elshobary, ME; Ammar, GAG; Gaber, A.; Alsanie, WF; Mansour, AT; El-Shenody, R. Impact of the commercial biostimulant liquid algae extract (TAM) and its bioactive molecules on the growth and antioxidant activities of chili pepper (Capsicum annuum). Plants 2021, 10, 1045. Ávila-Pozo P, Parrado J, Caballero P, Tejada M. Use of a Biostimulant Obtained from Slaughterhouse Sludge in a Greenhouse Tomato Crop Horticulturae 2022, 8, 622. https: / / doi.org / 10.3390 / horticulturae8070622 Colla, G.; Rouphael, Y. Biostimulants in agriculture. Sci. Hortique. 2015, 196, 1–2. Colla, G.; Rouphael, Y.; Canaguier,R.; Svecova, E.; Cardarelli, M. Biostimulant action of protein hydrolysates of plant origin produced by enzymatic hydrolysis. Front. Plant Sci. 2014 , 5 , 448. Ertani, A.; Pizzaghello, D.; Francioso, O.; Sambo, P.; Sanchez-Cortes, S.; Nardi, S. Capsium chinensis L. growth and nutraceutical properties are enhanced by long-term biostimulants: chemical and metabolomic approaches. Front. Plant Sci. 2014 , 5 , 1–2. González, M.; Cea, M.; Médine, J. ; González, A.; Díez, M.; Cartes, P. ; Montréal, C.; Naria, R. Evaluation of biodegradable polymers as encapsulating agents for the development of a controlled-release urea fertilizer using biochar as a carrier material. Sci. Environ. 2015 , 505 , 446–453. Hassan, SM; Ashour, M.; Soliman, AAE ; Hassanien, HA; Alsanie, WF; Gaber, A.; ElShobary,ME The potential of a new commercial seaweed extract to stimulate the morpho-agronomic and bioactive properties of Eruca vesicaria (L.) Cav. Sustainable Development 2021, 13, 4485. Kapoore RV, Wodd EE, Llewellyn CA, Algae biostimulants: A critical look at microalgal biostimulants for sustainable agricultural practices. Biotechnol Adv. 2021, 49, 107754. MASNEUF I. and DUBOURDIEU D., 1999. Assimilable nitrogen: interest of its dosage by formoltitration; study of some parameters at the origin of variations in its content in musts. Rev. Œnol., n°93, 31-32. Mosa W FA, Ali HM, Abdelsalam NR The utilization of tryptophan and glycine amino acids as safe alternatives to chemical fertilizers in apple orchards. Environ Sci Pollut Res Int 2021.January;28(2):1983-1991 Yes, L.; Zhao, X.; Bao, E.; Li, J.; Zou, Z.; Cao,K. Bio-organic fertilizer with reduced rates of chemical fertilization improves soil fertility and enhances tomato yield and quality. Sci. Rep. 2020, 10, 177. Rouphael Y; Colla G. Synergistic biostimulatory action: designing the next generation of plant biostimulants for sustainable agriculture. Frontiers in Plant science. 2018,9,1655.doi: 10.3389 / fpls.2018.01655 Searchinger T. The great balancing CCT: Installment 1 of creating a sustainable food future, World resources Institute: Washington DC, USA. 2013.pp 1-15. Tejada, M.; Rodríguez-Morgado, B.; Gomez, I.; Franco-Andreu, L.; Benítez, C.; Parrado, J. Use of biofertilizers obtained from sewage sludge on maize yield. EUR. J.Agron. 2016 , 78 , 13–19. Tejada, M.; Rodríguez-Morgado, B. ; Paneque, P.; Parrado, J. Effects of foliar fertilization of a biostimulant obtained from chicken feathers on maize yield. EUR. J.Agron. 2018 , 96 , 54–59.,

Claims

CLAIMS 1. Composition comprising a protein hydrolyzate of animal origin, preferably derived from the hydrolysis of by-products of pig farming, and a microalgae extract.

2. Composition according to claim 1, characterized in that it comprises a pig bristle protein hydrolyzate and / or a pig lung mucus protein hydrolyzate.

3. Composition according to any one of claims 1 and 2, characterized in that the microalgae extract is a spirulina extract, preferably a phycocyanin extract.

4. Composition according to any one of claims 1 to 3, characterized in that it contains the following amounts of amino acids.Amino Acids Composition according to the invention (mg / 100g of composition) TRYPTOPHAN 8-20, preferably 10-15 Aspartic acid 250-300, preferably 270-290 Threonine 120-150, preferably 125-145 Serine 160-200, preferably 170-190 Glutamic acid 500-700, preferably 525-650 Proline 150-200, preferably 165-195 Glycine 230-300, preferably 240-280 Alanine 180-240, preferably 200-230 Valine 160-230, preferably 185-215 Cysteine 30-80, preferably 40-70 Methionine 20-60, preferably 30-50 Isoleucine 100-180, preferably 130-160 Leucine 200-320, preferably 230-300. Tyrosine 60-140, preferably 10-80-120 Phenylalanine 100-140, preferably 115-135 Lysine 10-50, preferably 15-35 Histidine 40-80, preferably 45-65 Arginine 230-300, preferably 240-290 5. Composition according to any one of claims 1 to 4, characterized in that it contains amino acids whose molecular weight distribution is 3-4% between 1000 Da and 3000 Da, 2.5-3% between 800 Da and 1000 Da, 68-72% between 204 Da and 800 Da and 23-25% less than 204 Da.

6. Composition according to any one of claims 1 to 5 comprising 1-15% hydrolyzate and 1-5% microalgae extract, preferably spirulina extract, and optionally a support or vehicle acceptable in the agricultural field. 7.Process for the preparation of a composition according to any one of claims 1 to 6, characterized in that it comprises: - the provision of at least one protein hydrolyzate of animal origin, preferably derived from the hydrolysis of by-products of pig farming, - the provision of a microalgae extract, and - their mixtures.

8. Process for the preparation according to claim 7, characterized in that it comprises: - the provision of a chemical hydrolyzate of pig bristles and / or the provision of an enzymatic hydrolyzate of pig lung mucus - the provision of a spirulina extract, preferably an aqueous extract; and - their mixtures.

9. Use of a composition according to any one of claims 1 to 6 as an agricultural biostimulant.

10. Use of a composition according to claim 9, under normal irrigation conditions or under water stress conditions.

11. Use of a composition according to any one of claims 9 and 10, for large-scale crops, market gardening, viticulture, forestry, arboriculture and horticulture.

12. Use of a composition according to any one of claims 9 to 11, characterized in that said composition is applied by spraying onto the crop, preferably in quantities ranging from 1 to 10L / ha.

13. Kit comprising: - at least one protein hydrolyzate of animal origin, preferably derived from the hydrolysis of by-products of pig farming, preferably a pig bristle protein hydrolyzate and / or a pig lung mucus protein hydrolyzate, and a microalgae extract, in particular a spirulina extract, or a mixture thereof; - at least one support or vehicle acceptable in the agricultural field, - optionally instructions for use, for the preparation of a biostimulant.

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