The present invention discloses further a process for improving the efficiency of feed for promoting the growth of animals.

Background of the invention The well being and health and hence the economic value of livestock depends primarily on a good-functioning and well-balanced microbial ecosystem in the gastrointestinal tract of the host. Disturbance of this microbial eco-system will ultimately result in a decreased performance, often attended with infectious diarrhea. An important source of said disturbance is the presence in the gastrointestinal tract of undesired micro-organisms as contaminating pathogens in the animal's feed or in the near environment of the animal. All food and feed ingredients are naturally contaminated with bacteria, yeast and fungi (mainly mould-forming), the latter usually in the form of spores. At temperatures above 4 °C, most foods and feeds are ideal media for microbial growth and most of the time for subsequent toxic metabolite (e. g. endotoxin, mycotoxin) production by the in situ development of micro-organisms. Also in the environment of the animals, e. g. stable, faeces,..., is full of potential pathogenic bacteria.

Contamination of agricultural products with mycotoxin producing fungi is often unavoidable and of world-wide concern. Since humidity and temperature are important parameters for fungal growth, liquid food and feed are very susceptible to fungal contamination and growth and subsequent mycotoxin development. Mycotoxicosis can be caused by e. g. aflatoxins, ochratoxins, trichothecenes, zearalenones and citrinins. Mycotoxins cause a wide variety of adverse clinical signs depending on the nature and concentration of mycotoxins present, duration of exposure, the animal species, its age and nutritional health status at the time of exposure to the contaminated food and feed.

In view of the economical interest of modern animal husbandry systems to increase productivity maintain profitability, it has become a general practice to increase the growth rate by subjecting specific animals such as piglets to an early weaning. This early weaning however burdens the animal with a lot of adverse stresses, mainly of nutritional origin and are often accompanied by a more or less severe decrease in feed intake and energy deficiency and thus leading to a mobilization of body reserves by the animal. Feed maldigestion and malabsorption may further aggravate the situation and result in digestive upsets mainly due to bacterial and fungal overgrowth in and/or viral infections of the gastrointestinal tract. Such digestive pathology problem leads to severe weight losses and an increased mortality amongst the animals.

The digestive pathology as described above also leads to a very inefficient feed conversion. Thus the feed taken up by the animal is not efficiently converted. A low FCR (Feed Conversion Ratio is the ratio of the amount of feed consumed relative to the weight gain of an animal) indicates that a given amount of feed results in a growing animal gaining proportionately more weight. The latter situation indicates that the animal is able to utilize the feed more efficiently.

The administration of traditional antimicrobials or feed antibiotics is one way in which the digestive pathology is prevented and hence a way to lower the FCR. It is clear that antibiotic therapy for the treatment of numerous disorders and diseases results in the destruction or suppression of the overall intestinal microflora. This action on the intestinal microflora by the antibiotic can afterwards result in a non controlled proliferation of pathogenic microorganisms or can result in the build-up of resistance. This can give rise to diseases like diarrhea. Therefore, it has been necessary constantly to develop and use new antibiotics and mixtures thereof to the animals as described in e. g. EP Patent 597167, which discloses the use of an antibiotic mixture of gentamycin and lincomycin.

An important draw-back, however is that many antibiotics applied to the animals provoke resistance of the bacteria present in the animals and other microorganisms. Further, a number of the used antibiotics to the animals are the same or chemically very closely related to those antibiotics which are used in the fight against diseases provoked by bacteria and other micro-organisms in humans. As such, there has been an increasing concern in the public opinion that the resistance found in the microorganisms in the livestock will be

transferred to the disease provoking microorganisms living in human beings, wherefore these cannot be controlled with the present human antibiotics at disposal. ~ Alternative feed additives to improve the animal's well-being and hence its ability to efficiently convert feed into food products are increasingly being used and include feed acidifiers for improved feed preservation and/or improved protection of the digestive tract against proliferation of pathogenic bacteria (WO 98/43634). Also medium-chain fatty acids (MCFA) having 6 to 12 carbon atoms have been reported for use in feedstock; e. g. US Patent no 5,462, 967 discloses the use of MCFAs having 6 to 12 carbon atoms for anti-protozoiasis effect and suppression of an excess formation of systematic fat of, in particular, domestic fowl.

With regard to the relative expensive cost factor of feed in the production of food- producing animals, it is clear that an additional aspect of lowered feed conversions will directly improve the profitability of a feed producer.

It is an object of the present invention to provide a composition which provides an effective inhibition of digestive pathology in the animal's gastrointestinal tract. It is a further object of the present invention to provide a composition which improves the microbial balance of the intestinal microflora. It is a further object of the present invention to provide a composition which provides a low FCR without increasing the feed cost per unit weight. It is a further object to the present invention to provide a composition which enhances growth. It is a further object of the present invention to provide a method of enhancing weight gain and feed efficiency in an animal.

Summary of the invention The invention relates in general to a composition comprising a MCFA component and at least one additional growth promoting component selected from the group comprising organic acids, inorganic acids, animal feed antibiotics, conventional growth promoters and plant extracts like oreganum and allicin.

The compositions according to the present invention surprisingly led to a synergistic antimicrobial activity against bacteria, yeast, and moulds. Said compositions also lead to a much increased growth and a much reduced FCR.

In a preferred embodiment, the invention relates to a composition comprising a MCFA component and at léast one additiiiEl growtipromoting component selected from the group comprising animal feed antibiotics, conventional growth promoters and plant extracts and further comprises a growth promoting component selected from the group comprising organic acids and inorganic acids.

In another preferred embodiment, the invention relates to a composition comprising a MCFA component and at least one growth-promoting component selected from the group comprising probiotics, synbiotics, enzymes, and bio-active components.

In a particularly preferred embodiment, the MCFA component comprised in a composition according to the invention is provided in the form of an emulsion. In an even more preferred embodiment, said emulsion further comprises a surfactant, preferably a non- ionic poloxamer surfactant.

The invention further relates to methods for improving growth and/or reducing feed conversion and/or for improving feed value and/or for improving general health and well being of an animal by providing said animal with a feed comprising a composition according to the present invention.

Detailed description of the figure Figure 1 illustrates the set up for poultry trials performed as explained in example 2 and 3.

Detailed description of the invention Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art.

In this specification and the appended claims, the singular forms"a","an", and"the" include plural references unless dictated otherwise.

As used herein, the term"composition"is construed to mean a feed additive.

The term"feed conversion"is used to describe efficiency in animal feed uptake and refers to the units of feed consumed divided by the units of animal weight gain over a specific

time period. The"Feed Conversion Ratio"is the ratio of the amount of feed consumed relative to the weight gain of an animal.

The present invention relates to improved feed conversion activities of animals without concomitant substantial or significant stimulation of feed intake. Typically the feed intake is the same or decreased in treated animals as compared to untreated animals. New compositions and methods for obtaining the above are available.

As used herein the expression"improving the feed conversion"and cognate expressions such as"feed conversion improvement"refer to improving feed utilization efficiency and/or improving growth rate. That is, in accordance with the present invention, treated animals (as compared to untreated animals) can have substantially the same feed intake and grow at an increased growth rate, can have decreased feed intake and grow at substantially the same growth rate, or can have decreased feed intake and grow at an increased growth rate. The term"growth"as used herein refers to a gain in weight as in gained weight by increased tissue deposits on the animal's carcass yielding the choice meat.

In accordance with the present invention, in a first aspect, a composition is provided comprising a MCFA component and at least one growth-promoting component selected from the group comprising organic acids, inorganic acids, animal feed antibiotics, conventional growth promoters and plant extracts.

In one embodiment, a composition is provided wherein the MCFA component consists essentially of MCFA, salts, or derivatives, or mixtures thereof. A particular suitable phase of the MCFA component according to the present invention is solid or semi-fluid, more in particular emulsions. Accordingly, the MCFA component of the composition according to the present invention may be a single MCFA, a single MCFA salt, a single MCFA derivative, a mixture of MCFAs, a mixture of MCFA salts, a mixture of MCFA derivatives, a mixture of MCFA's and MCFA salts, a mixture of MCFAs and MCFA derivatives, a mixture of MCFA salts and MCFA derivatives, a mixture of MCFAs, MCFA salts and MCFA derivatives.

As used herein, the term"MCFA component"refers to a fraction in the composition according to the present invention consisting essentially of MCFA, salts, or derivatives, or mixtures thereof. As used herein, the term"MCFA"refers to a medium chain fatty acid with

said"medium chain fatty acid"meaning a saturated fatty acid, unsaturated fatty acid, or- mixture thereof, having 6 to 14 carbon atoms. By"medium chai aturated fatty acid,"as used herein, is meant C6 (caproic), C8 (caprylic), C10 (capric), C12 (lauric), or myristic (C14) saturated fatty acids, or mixtures thereof. Particularly suitable is the use of a C8/C10 mixture in equal amounts. The C7, Cg, C11s and Cis saturated fatty acids are not commonly found, but they are not excluded from the possible medium chain fatty acids.

As used herein, the term'MCFA salt"refers to a salt of the free fatty acid. As used herein, the term"free fatty acid"refers to a, underivatised fatty acid, i. e. a fatty acid not converted into a salt, an amide, an ester etc. As used herein, the term MCFA derivative refers to a medium chain fatty acid whose carboxylic acid group is reversibly converted into another group to form amides, esters, glycerides. In this specification, the term MCFA derivative excludes MCFA salt.

As used herein, the term"growth-promoting component"refers to a compound or composition which exerts a growth-promoting activity or effect within a living vertebrate host, which excludes MCFA, salts, or derivatives thereof, or mixtures thereof. Said growth- promoting component is usually (part of) a feed additive or feed supplement.

In another embodiment, the invention provides for a composition comprising a MCFA component and at least one growth-promoting component selected from the group comprising pre-biotics, pro-biotics, synbiotics, proteases, and bio-active agents.

The term"prebiotic"as used herein refers to carbohydrates. Certain non-digestible carbohydrates, such as components of soluble dietary fibre may stimulate the growth or activity of beneficial/probiotic bacteria.

"Probiotics"as used herein are by definition living microbiological dietary supplements that have beneficial effects to the host through their function in the digestive tract. In order to be effective the probiotic micro-organisms must be able survive the digestive conditions, and they must be able to colonise the gastrointestinal tract at least temporarily without any harm to the host. Only certain strains of micro-organisms have these properties. Most preferred probiotic micro-organisms according to the invention include, but are not limited to members of two bacterial genera: Lactobacillus and Bifidobacterium.

As used herein"bio-active components"refer to compounds which have a biological acitivity and include but are not limited to component which are present in blood plasma, such as but not limited to lactitol, maltitol, guar gom, inulin, raffinose and verbascose.

More in particular, additional useful growth-promoting components include but are not limiting to prebiotics such as oligosaccharides including inulins, fructo-oligosaccharides, and galacto-oligosaccharides ; probiotics such as Bifidobacterium thermophilum and infantis, Lactobacillus acidophilus, bulgaricus, casei, lactis, plantarum, and reuteri, Bacillus subtilis and cereus, Streptococcus faecium, diacetilactus, and thermophilus, Enterococcus faecium and faecium, Torulopsia, Aspergillus otyzae, and Streptomyces ; including their vegetative spores, non-vegetative spores (Bacillus) and synthetic derivatives; synbiotics; enzymes such as phytase, glycanases, lipases, acid proteases from Rhizopus rhizopodiformis, Aspergillus niger, and the genus Tramates, and neutral to alkaline proteases from Bacillus subtilis, licheniformis, and natta ; herbs such as Mimosaceae and oregano, including extracts and essential oils thereof; and fungi belonging to the class Basidiomycotina comprising genera belonging to the orders Agaricales and Aphyllophorales, such as Armillariella mellea (Fr. ) Karst, Tricholoma matsutake (S. Ito et Imai) Sing. , Lentinus edodes (Berk. ) Sing. and Shiitake, Coriolus versicolor (Fr. ) Quel., Grifola gigantea (Fr. ) Pilat, Favolus arcularius (Fr. ) Ames, Ganoderma (Reishi), Cordyceps, Coriolus or Grifola (Maitake), either alone or in any combination with each other may be used as growth-promoting components in this specification. Other bio-active components such as present in blood plasma are also suitable.

The presence of a MCFA component in combination with a growth-promoting component in said new composition, according to the present invention has a synergistic effect on feed conversion improvement leading to much reduced FCRs.

Compared to FCR's obtained with single-growth-component feed additives, compositions of the present invention provides substantially higher feed conversion and substantially lower FCR. As used herein, the term"single-growth-component feed additive" refers to an additive comprising at least one growth component within a single class of growth-promoting components. The term"class"of growth-promoting components as used herein refers to a group or set of growth components sharing common characteristics and/or functionalities such as e. g. class of antibiotics, class of prebiotics, class of probiotics, class of

synbiotics, class of herbs, class of conventional growth promoters, class of organic acids, and class of inorganic acids.

Compositions of the present invention provide at least 4-times higher antimicrobial effects compared to results obtained with single-growth-component feed additives.

In one embodiment, the MCFA in the composition according to the present invention is selected from the group of medium chain saturated fatty acids. Useful medium chain saturated fatty acids include but are not limited both even and odd fatty acids such as caproic acid (C6), heptanoic acid (C7), caprylic acid (C8), pelargonic acid (Cg), and capric acid (C10), including mixtures of each other. In the present invention, particular useful are mixtures of specific different saturated fatty acids, the individual specific saturated fatty acids containing a different number of carbon atoms. Such mixtures provide optimal antimicrobial properties.

In homologues series of fatty acids, the bactericidal efficiency has been found to increase with increasing chain length. Fatty acids with a chain length of 8 to 10 carbon atoms show optimal antimicrobial activity.

In the present specification, undecanoic acid and lauric acid are suitable medium chain saturated fatty acids and also butyric acid, valeric acid, tridecanoic, and myristic acid may be equally suitable in the present invention.

Substituted MCFAs such as 2-methyl-tetradecanoic acid, 5-methyltetradecanoic acid, 2, 2-dimethyltetradecanoic acid, including, branched, monobasic, and dibasic fatty acids may be equally suitable in the present invention. In particular the non-synthetic acids are suitable.

In a particular useful embodiment, the MCFA in the composition according to the present invention is selected from the group of C 8-10 medium chain saturated fatty acids.

The currently accepted theory for the mechanism according to which the fatty acids exert antimicrobial activity is that the lipid microbial cell membrane is permeable for the undissociated fatty acid, as a consequence of which the fatty acid is capable of passing across the microbial cell membrane towards the more alkaline interior. Because of the higher intracellular alkalinity, the fatty acid is dissociated, thus involving a decrease of the

intracellular pH below the survival level. The fatty acid thus in fact acts as a protonophore, which increases inward leak of H+ and which makes that the efflux of H+ is too slow to allow the intracellular pH to be increased again. The physicochemical properties of the fatty acids which allow them to act as protonophores, may vary and depend on numerous parameters.

Examples of such parameters are the chain length, amphotheric characteristics and pKa of the fatty acid as well as the physicochemical environment, precipitations, the pH at the place of action and the chemical composition of the microbial envelope which determines the passage of the fatty acids through the membrane. In this respect, the better performance of the fatty acid containing 8-10 carbon atoms is attributed to the extreme permeability of the microbial cell membrane for this fatty acid. In addition, destabilization of plasma membrane alters the energy metabolism of the micro-organism.

Concentrations up to lu105 ppm of MCFA component in the animal feed are suitable.

In further embodiment, up to 5x104 ppm, in a further embodiment up to 1x104 ppm, in a further embodiment up to 5x103 ppm, and yet in a further embodiment up to 1. 5x103 ppm in the animal feed are useful concentrations. In a further embodiment concentrations as low as 102 ppm were effective.

According to a further embodiment, a composition is provided wherein the MCFA component comprises at least one MCFA salt and at least one MCFA derivative.

According to a further embodiment, a composition is provided wherein the MCFA component comprises at least one MCFA salt. In this specification, mixtures of two or more salts of the free fatty acids are particulary suitable. Non-limiting examples of suitable MCFA salts in the present invention include alkali metal salts such as lithium salts, sodium salts, potassium salts, and the like ; alkaline earth metal salts such as magnesium salts, calcium salts, barium salts, and the like ; various metal salts such as zinc salts, aluminum salts, iron salts, manganese salts, and the like ; organoamine salts such as monoethanloamine salts, diethanoamine salts, trietholamine salts, and the like ; basic amino salts such as lysine salts, ornithine salts, arginine salts, histidine salts, hydroxylysine salts, and the like ; and alkali metal salts such as ammonium salts, and basic amino acid salts.

In a further embodiment of the present invention, a composition is provided wherein the MCFA comprises at least one MCFA salt selected from the group comprising ammonium salts, sodium salts, potassium salts, and calcium salts.

The use amount of MCFA salts in the present invention in animal feed is usually 0. 001% to 25% by weight. The use amount of MCFA salts varies with factors such as the animal host, the animal's age, the kind of ingredients other than MCFA salts etc.

According to a further embodiment, a composition is provided wherein the MCFA component is at least one MCFA derivative. Suitable MCFA derivatives are selected from the group comprising mono-, di-, and tri-glycerides. A molecule of mono-, di-, or triglyceride is composed of a backbone of glycerol to which respectively one ("mono"), two ("di") or three fatty acids ("tri") are bound. Any combination of saturated, monounsaturated, or polyunsaturated fatty acids can be in a mono-, di-, or triglyceride molecule. A monounsaturated fatty acid has one site where hydrogen atoms can be added. A polyunsaturated fatty acid has two or more sites for additional hydrogen atoms.

Examples of naturally occurring substances which are rich in MCFA derivatives such as mono-, di-, and triglycerides include but are not limited to coconut oil, palm kernel oil, babassu oil, cohune oil, tacum oil, cuphea oil derived from plant seeds, milk of mammalian species, such as milk from horse, rat, goat and rabbit, or butterfat. Also commercial sources of chemically structured or tailor-made mono-, di-, and triglycerides may be useful, or mixtures of these.

Suitable concentrations of MCFA derivatives such as mono-, di-, and triglycerides in the feed are ranged from 0.20% to 12% by weight. In a further embodiment, MCFA derivative concentrations may range from 0.25% to 10% by weight in the feed. In a further embodiment, MCFA derivative concentrations may range from 0.5% to 5% by weight in the feed.

In one embodiment of the present invention, the growth promoter component may be a single compound or a mixture of compounds within a single class of growth-promoting components or mixtures of single or two or more compounds from a single or two or more classes.

In one embodiment of the present invention, a composition is provided wherein the growth-promoting component a least one component selected from the group comprising organic acids and inorganic acids. Accordingly, the growth-promoting component of the composition according to the present invention may be a single organic acid, a single inorganic acid, a mixture of organic acids, a mixture of inorganic acids or a mixture of organic and inorganic acids.

In a preferred embodiment of the present invention, wherein the composition, which comprises a MCFA component and at least one growth-promoting component selected from the group comprising animal feed antibiotics, conventional growth promoters, or plant extracts, further comprises a growth-promoting component selected from the group comprising organic acids and inorganic acids. Thus, such preferred composition comprises a MCFA, a growth promoting element being an animal feed antibiotics, conventional growth promoter or plant extract and additionally also comprises at least one organic and/or inorganic acid.

In a further embodiment, a composition is provided wherein the growth-promoting component is an organic acid. In a further embodiment, a composition is provided wherein the growth-promoting component is an organic acid being a C1 8 carboxylic acid selected from the group comprising unsubstituted carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, valerianic acid, and caproic acid, substituted carboxylic acids such as adipic acid, maleic acid, succinic acid, citric acid, fumaric acid, tartaric acid, lactic acid, gluconic acid, malic acid, and ascorbic acid, including cyclic carboxylic acids such as picolinic acid. The organic acid component may be a single unsubstituted carboxylic acid, a single substituted carboxylic acid, a mixture of unsubstituted carboxylic acids, a mixture of substituted carboxylic acids and a mixture of unsubstituted carboxylic acids and substituted carboxylic acids including saturated, unsaturated, cyclic and aliphatic carboxylic acids and metal complexes and salts thereof. Also single racemic forms and racemic mixtures may be used.

In a further embodiment, when added in feed for animals, useful concentrations of such carboxylic acids range from 0.05 eq/kg to 0.25 eq/kg feed. In further embodiments, concentrations of such carboxylic acids range from 0,10 eq/kg to 0.20 eq/kg feed, from 0,10 eq/kg to 0.15 eq/kg feed or from 0.12 eq/kg to 0.18 eq/kg feed.

In yet a further embodiment,-a composition is provided-wherein the growth-promoting component is an inorganic acid including strong inorganic acids in small quantities such as perchloric acid, hydroiodic acid, hydrobromic acid, hydrochloric acid, sulfuric acid, and nitric acid and weak inorganic acids such as phosphoric acid, hydrofluoric acid, hypochlorous acid, and nitrous acid. Suitable concentrations of weak and strong inorganic acids which are useful range from 0.1-0. 3% to 1-1.5% by weight.

In another embodiment according to the present invention, a composition is provided wherein the growth-promoting component is an animal feed antibiotic. Non-limiting examples of useful animal feed antibiotics include avoparcin, bacitracin such as zinc bacitracin, chlortetracyclin, flavophospholipol (flavomycin), furadox, gentamicin, lasalocid, lincomycin, monensin, neomycin, oleandomycin, oxytetracyclin, sarimomoicin, spiramycin, sulfametazine, tetracycline, tylosin, virginiamycin, salinomycin, avilamycin. In a further embodiment, a useful concentration of an animal feed antibiotic ranges from 0.5 ppm to 250 ppm in animal feed. In further embodiment, a useful antibiotic concentration for animal feed ranges from 1 ppm to 150 ppm. In further embodiment, a useful antibiotic concentration for animal feed ranges from 2 ppm to 100 ppm. In further embodiment, a useful antibiotic concentration for animal feed ranges from 2.5 ppm to 50 ppm. In yet a further embodiment, a useful antibiotic concentration for animal feed ranges from 2.5 ppm to 5 ppm.

In another embodiment according to the present invention, a composition is provided wherein the growth-promoting component is a conventional growth promoter selected from the group comprising nitrovin, olaquindox, carbadox, and cyadox. Concentrations of such conventional growth promoters ranges from 20 ppm to 150 ppm but usually range from 50 ppm to100 ppm.

In another embodiment, the composition according to the present invention comprises an amount from 0.5% to 99.9% by weight of MCFA component. In yet another embodiment, an amount from 1 % to 99,9% by weight of MCFA component is comprised in a composition according to the present invention. In a further embodiment, an amount from 50% to 99,9% by weight of MCFA component in a composition according to the present invention. In yet another further embodiment, an amount from 70% to 99.9% by weight of MCFA component is comprised in a composition according to the present invention. In a further embodiment, an

amount from 85% to 99.9% by weight of MCFA component is comprised in a composition according to the present invention. In yet a further embodiment, an amount from 95% to 99.9% by weight of MCFA component is comprised in a composition according to the present invention.

In another preferred embodiment, the composition according to the invention comprises - silicium dioxide, in a concentration ranging from 10 % to 20 % by weight and preferably in a concentration of 30 % by weight, - an aromatic compound, in a concentration ranging from 5 % to 25% by weight and preferably in a concentration of 10 % by weight; - semolina e. g. rice or wheat semolina in a concentration ranging from 5% to 25% by weight and preferably in a concentration of 10 % by weight; and - a mixture of the C6, C8, and C10 MCFA, preferably in liquid form, in a concentration ranging from 0.5% to 99.9% by weight, more preferably ranging from 1% to 99,9% by weight, even more preferably ranging from 50 % to 99.9 % by weight. In a most preferred embodiment, the concentration of MCFA mixture comprises 50 % by weight.

Said mixture of the C6, C8, and C10 MCFA preferably comprises C6 MCFA in a concentration ranging from 0 % to 10%, Cs MCFA in a concentration ranging from 40 % to 50% and C10 MCFA in a concentration ranging from 40 % to 50%. Ce, Cs and C10 MCFA are preferably obtained from palm or coco. In another preferred embodiment, this composition, comprising silicium dioxide, an aroma, semolina and a MCFA mixture, further comprises a growth promoting element according to the definition of the present invention.

According to this specification, a composition is provided comprising a MCFA component and at least one growth-promoting component. It is generally recognized by a skilled person in the art that supplemental ingredients are being used, e. g. various additives such as amino acids, minerals, vitamins, enzymes, etc. , with various objects, such as nutrient replenishment, nutrient fortification, improvements of digestion and absorption, disease prevention, etc. t In a preferred embodiment, the composition according to the invention comprises a MCFA component and at least one growth-promoting component, whereby the MCFA component is provided in the form of an emulsion. In an even more preferred embodiment,

the invention relates to a composition, wherein said emulsion comprises said MCFA component,; iivaterhickening agent and a surfactant.

By the wording"surfactant"as used herein is meant any agent that acts as a solubiliser and/or as an emulsifier with or without thermo reversible gelling properties. The wording"thickening agent"is intended to include thickening agents with or without thermo reversible properties.

If only one surfactant and one thickening agent are used in the composition according to the invention, they must be selected with care and in suitable amounts so that at least one of these elements has thermo reversible gelling properties.

The total amount of the surfactant (s) and thickening agents should be present in an amount effective to produce a homogenous formulation. In a preferred embodiment, the surfactant is used in the emulsion in a concentration from 0.1 % to 10 % by weight. In a further embodiment, the surfactant is used in the emulsion in a concentration from 2.5 % to 10 % by weight. In a further embodiment, an amount from 4.0 % to 10 % by weight of surfactant is comprised in the emulsion.

In another preferred embodiment, the thickening agent is used in the emulsion in a concentration from 0 % to 1 % by weight. In a further embodiment, the thickening agent is used in the emulsion in a concentration from 0.1 % to 1 % by weight. In a further embodiment, an amount from 0.2 % to 1 % by weight of thickening agent is comprised in the emulsion. In yet another embodiment the thickening agent is used in the emulsion in a concentration of 0.5 % to 1 % by weight.

In yet another embodiment, the MCFA component is used in the emulsion in a concentration from 0.1 % to 99.9 % by weight. In a further embodiment, the MCFA component is used in the emulsion in a concentration from 25 % to 99.9 % by weight. In a further embodiment, an amount from 40 % to 100 % by weight of MCFA component is comprised in the emulsion. In yet another embodiment the MCFA component is used in the emulsion in a concentration of 75 % to 100 % by weight.

In another embodiment, water is used in the emulsion in a concentration from 0.1 % to, . 9 % by weight. In a further embodiment, water is used in the emulsion in a concentration from 25 % to 99.9 % by weight. In a further embodiment, an amount from 40 % to 100 % by weight of water is comprised in the emulsion. In yet another embodiment water is used in the emulsion in a concentration of 75 % to 100 % by weight.

According to another embodiment, the surfactant is preferably selected from the group comprising non-ionic surfactants, more preferably from any non-ionic poloxamer known in the art. Poloxamers are synthetic block copolymers of hydrophilic ethylene oxide chains and hydrophobic propylene oxide chains, having the general formula HO-- [C2 H4 O] a-- [C3 H6 O] b-- [C2 H4 O] a--H, a and b representing the number of the hydrophilic and hydrophobic chains respectively. By choosing the surfactant (s) having hydrophobic and hydrophilic domains in appropriate amounts, it is possible to achieve a composition having suitable thermo-reversible gelling properties, i. e. the viscosity of the composition system is reversible with temperature.

In a particularly preferred embodiment, the invention relates to a composition wherein said surfactant is selected from the group comprising Lutrol F68. RTM and Lutrol F127. RTM.

Lutrol F68. RTM. , which also has the name poloxamer 188 and wherein a=80 and b=27, and Lutrol F127. RTM. , which also has the name poloxamer 407 and wherein a=101 and b=56, are commercially available and obtainable from BASF.

In another particularly preferred embodiment, the invention relates to a composition wherein said thickening agent is Rhodigel 80.

An example of an emulsion comprising MCFA according to the invention may consist of an emulsion comprising 44.87 % by weight of MCFA, in particular a mixture of C6, C8 and Clo MCFA, 50 % by weight of water, 0.125 % by weight of the thickening agent Rhodigel 80 and 5 % by weight of Lutrol F68.

In a further embodiment, a composition according to the present invention is particularly useful as a antimicrobial agent, particularly in livestock feed. In a further embodiment, a composition according to the present invention is particularly useful for animal

feed. In a further embodiment, a composition according to the present invention is particularly usefu-Ffor p-oultry and pig feed.

Accordingly, the use of a composition according to present invention has been proven to be particularly suitable for intestinal ecosystem improvement and/or lowering feed conversion ratio's and/or growth enhancement.

Further, a composition of the present invention may be suitable for intestinal function improvement and/or carcass quality improvement. When fed to dairy animals such as dairy cows, goats and ewes, a composition of the present invention may improve milk production.

It is a second aspect of the present invention to provide an animal feed comprising the synergetic composition according to the invention from 0. 001% to 20% by weight and comprising standard animal feed from 80% to 99.999% by weight. As used herein, the term "standard animal feed"refers to feed for animals, i. e. feed that can be used in the animal husbandry field and is suitable to be fed to meat-producing animals to supply part or all of the meat-producing animal's nutrient requirements. Main ingredients of standard animal feed include but are not limited to wheat flour, starch, dextrin, cereal grains such as corn, milo, etc. , oil seed meals, such as soybean meal, rapeseed meal, cottonseed meal, linseed meal, chaffs and brans, such as rice bran, de-oiled rice bran, wheat bran, fish meals, oils and fats, such as beef tallow, soybean oil, palm oil, coconut oil, and fish oil, minerals like limestone, phosphates, trace elements and vitamins.

In a further embodiment, said animal feed comprises a composition according to the present invention from 0. 01% to 10% by weight. In a further embodiment, said animal feed comprises a composition according to the present invention from 0. 1% to 10% by weight. In a further embodiment, said animal feed comprises a composition according to the present invention from 0.5% to 5% by weight. In a further embodiment, said animal feed comprises a composition according to the present invention from 0. 1% to 5% by weight. In a further embodiment, said animal feed comprises a composition according to the present invention from 0.5% to 2% by weight.

According to the present invention, an animal feed is provided for use as feed for meat-producing animals. As herein used, the term"meat-producing animals refer to livestock animals including but not limited to cattle such as ruminants, sheep, swine including pigs and

hogs, horses, and poultry, and their progeny, such as sucking pigs, piglets, calves, lambs kids, foals and chickens ëtc.

Also fishes, such as eel, carps, trout, rainbow trout, yellowtail, sea bream, silver salmon, gold fishes, colored carp, tropical fishes; shellfishes; crustaceans; are examples of the animals covered by the composition and/or animal feed of the present invention.

Also pets, such as dogs, cats, rabbits, hamsters, and their progeny are examples of the animals covered by the composition and/or animal feed of the present invention.

In a further embodiment, an animal feed according to the present invention is used for poultry or pig feed, in particular during the early life stages. Non-limiting examples of poultry that may be considered in the present invention include chickens, ducks, geese, guinea fowl, peafowl, pigeons, and turkeys. As used herein, the wording"during early life stage of poultry" refers to a life stage comprised between 1 day and 4 weeks. As used herein, the wording "during early life stage of pig"refers to a life stage comprised between the birth and 1 week, preferably 2 weeks after weaning. In a preferred embodiment an animal feed according to the invention is fed to piglets during a period comprised between weaning and up to 20 kg. In a further preferred embodiment an animal feed according to the invention is fed to pigs during a period comprised between 20 kg and slaughter weight. In a further preferred embodiment an animal feed according to the invention is fed to poultry during a period comprised between 1 day and 4 weeks.

A further aspect of the present invention relates to a method for the improvement or prevention of digestive pathology and/or growth improvement and/or for reducing feed conversion and/or for improving feed value and/or for improving health and well-being of an animal by providing said animal with a feed comprising a composition as provided in this specification.

The compositions of the present invention may be added either directly to the animal's feed or may be added as a premix. Optionally, the composition can be dosed via dilution in the drinking water or via a spraying technique to the animal. The compositions according to the present invention will mostly be present in a form of a dry powder or mini-granules but may also be present in humidified, pasta-like emulsion-like or liquid form. A powder additive may be prepared by dry-blending of the ingredients, but it may also be prepared by wet- blending of the ingredients followed by drying, grinding and possible sifting. A mini-granulate

may be prepared the same way although to begin with, a sufficient amount of liquid may be, added of an appropriate'kincr (e. g. wafer) in order to obtain sufficient adhesion power between the particles of the ingredients.

Accordingly, the present invention relates to induction by feeding the animal with a composition of the present invention of changes in the microbial ecosystem in the gastrointestinal tract of the animal in a specific way resulting in an improved gastrointestinal ecosystem. In particular when using Lentinus edodes, the total amount of enteric pathogens are in a first stage enumerated in the lumen of the gastrointestinal tract, i. e. a selective enrichment of the enteric pathogens within the lumen of the gastrointestinal tract, and in a second stage, the enumerated enteric pathogens are very quickly excreted from the gastrointestinal tract of the animal. As used herein, the term"enteric pathogens"refers to an undesired population of pathogens.

The compositions according to the present invention have antimicrobial, especially antifungal and/or antiviral and/or antibacterial activity.

As will be appreciated, there are a large number of such enteric pathogens including but not limiting to Gram negative bacteria like Salmonella, Escherichia, Shigella, Klebsiella, Erwinia, Yersinia, Campylobacter, Helicobacter, Vibrio, and Pseudomonas ; Gram positive bacteria like Clostridium ; viruses like Norwalk virus, Norwalk-like viruses and Rotavirus; protozoa like Crytosporidium, Entamoeba, Giardia, and Dientamoeba ; fungi from the genera comprising Aspergillus, Candida, Cephalosporum, Fusarium, Penicillum including fungi belonging to the Fungi imperfect ! ; yeast including Saccharomyces and Hemiascomycetes.

The present invention would be suitable for the suppression of the development these pathogens in feed and in the gastrointestinal tract of animals.

By fast elimination of enteric pathogens from the gastrointestinal tract, in a second instance, better performances, which reflect in daily growth and feed conversion of the treated animals are obtained. The overall growth promoting effect of the feed additive composition of the present invention is readily and clearly visible at the elution level of the enriched enteric pathogen population from the gastrointestinal tract of the animal.

The administration of a composition according to the present invention to animals allows for a specific sequential action in the gastroiritestinal tract, i. e. the enumeration ofthe enteric pathogens prior to a wash-out of the enumerated enteric pathogens. As a result of the synergistic action of the compositions of the present invention, efficient inhibition of microbial outgrowth by killing of the microbial cells is obtained.

Examples The following examples of the invention are exemplary and should not be taken as in any way limiting.

Example 1 : Antimicrobial effect of the compositions of the present invention on bacteria, yeast, and mould development.

As used herein, the term"control feed"refers to a standard animal feed for meat-producing animals.

Solid feed was used. The test was performed in vitro. No tests in vivo were performed.

The antimicrobial effect on development of bacteria, yeast and moulds was monitored (Table 1. ) Evaluation of antimicrobial effect was performed as follows : Microorganisms were incubated with test substance (eventually blank) at different concentrations. The difference between the amount of bacteria at time 0 and at time 3 hours (after incubation) was calculated. This difference is a measure of the antimicrobial activity of the product. Results are expressed in Table 1.

Table 1 Decrease (expressed in delta log units) of different types of micro-organisms after exposure to the diet mentioned in the table during 3 hours at 37 °C. Initial bacterial load was 105 CFU/g. Diet Decrease of type of micro- organism Bacteria Yeast Moulds control 0.73 0.54 0.55 control + Lentinus edodes 1. 35 0.78 0.85 control + formic acid 1. 21 1.18 1.35 control + phophorous acid 0. 75 0.60 1.20 control + Salinomycine 1. 19 control + Amoxyciline 2. 31 control + inulin 0. 85 control + Bacillus sp. 0.77 control + Oregostim 1. 18 1, 23 1,46 -control + MCFA's-----2. 20--3. 30- 3.00 control + Lentinus edodes + MCFA's 2, 96 4, 06 3,80 control + formic acid + + MCFA's 3, 02 3,98 3,74 control + phophorous acid + MCFA's 2. 76 4.12 3.92 control + Salinomycine + MCFA's 2. 31 control + Amoxyciline + MCFA's 2. 89 control + inulin + MCFA's 2. 23 control + Bacillus s. + MCFA's 3, 04 control + Oregostim + MCFA's 3, 01 4, 02+ 3, 88+

From Table 1, it is clear that the combination of the use of a MCFA component with a growth- promoting component as in the compositions of the present invention has a synergistic effect on antimicrobial activity. The higher the delta log unit, the higher the antimicrobial effect. We conclude that compared to antimicrobial activity obtained with single-growth-component feed additives, feed additives comprising a composition according to the present invention provides up to 3 to 4 times higher antimicrobial effects.

Example 2: For the in vivo poultrv trials, following set up was performed: One battery consisted of 4 pens (see figure 1). The animals were one-day chickens with a density of 40 animals per pen. The animals were kept on straw and the total area per pen was 2 m2. At the start of the trial, the chickens were warmed by an infra red bulb and lightned constantly. The chickens were fed different feed at libitum, as illustrated in table 2. Feed A was control feed, feed B was control feed + MCFAs, feed C was control feed + MCFAs + additive, feed D was repitition of feed C. At regular time intervals, the chickens were weighed individually and feed intake was measured. Next, feed conversion was calculated. The results are illustrated in table 2A and 2B. This trial was performed using male broilers during 35 days.

Table 2 Influence of MCFA's in combination with different agents on chicken performance Diet Daily growth FCR (g/chicken/day) Control 53. 16 1. 61 control + Lentinus edodes 53. 22 1.60 control + formic acid 52. 18 1. 55 control + hophorous acid 52.23 1. 56 control + Salinomycin 54. 06 1. 60 control + Avilamycin 53. 99 1. 59 control + inulin 51. 09 1. 65 control + Bacillus sp. 53. 22 1. 61 control + Oregostim 53. 03 1. 66 control + MCFA's 55. 98 1. 53 control + Lentinus edodes + MCFA's 56.71 1.52 control + formic acid + + MCFA's 53.22 1.63 control + hophorous acid + MCFA's 52. 18 1. 69 control + Salinomycin + MCFA's 56. 46 1. 56 control + Avilamycin + MCFA's 56. 12 1. 59 control + inulin + MCFA's 53. 78 1. 60 control + Bacillus sp. + MCFA's 52. 68 1. 63 control + Oregostim + MCFA's 53. 77 1. 61

From table 2, it is clear that the combination of the use of a MCFA component with a growth promoting component as provided by the compositions of the present invention has a synergistic effect on growth and feed conversion ratio of the animal. We conclude that compared to FCR's obtained with single-growth-component feed additives, the compositions of the present invention provides substantially higher feed conversion and substantially lower FCRs.

Example 3 In this example, the antimicrobial effect of the compositions of the present invention, wherein MCFA is used as an emulsion was evaluated in vivo by means of poultry trials.

The following set up was performed. The experimental farm consisted of 4 pens wherein the animals were kept on straw. The animals were male broilers of 1 day old. The animals were kept on straw and the total area per pen was 2 m2. The pens had an available surface of 2 m2 and are illustrated on figure 1. The broilers were placed at a stocking density of 40/pen, to obtain an average of 38-39 kg body weight2 at 35 days of age. For each evaluation, the total number of broilers used in the trial was 40 times 4 broilers. 40 broilers per treatment was the minimum in order to reduce the statistical deviation on technical performances. The animals were not vaccinated at the beginning of the experiment. Optimal housing temperature was provided by central water heating and infrared bulbs (1 per pen) and the pens were lightened constantly.

All broilers received feed (1 feeder/pen, manual distribution) and water (1 hanging drinker per pen) ad libitum. Feed was a standard broiler feed and the same for all animals. The chickens were fed with different feeds at libitum, Drinking water was fortified as follows : treatment 1 contained no additives in water, treatment 2 contained 0.001 % of an emulsion which contained 50 % water, 0.125 % xanthan, 5% lutrol F68 nd 44.875 % MCFAs, while treamtent 3 contained avilamycin. Average pen weight and feed intake were recorded weekly. The

effects of the feed compositions on the performances of male broilers as recorded after 35 days are illustrated~in-ta-bE3.

Table 3. Effect of the different feed compositions on the performances of male broilers (0 to 35 days) Daily growth FCR (g/chicken/day) Control 56.34 1.454 Control + avilamycin 57. 31 1. 468 Control + emulsion 59.29 1.404 From this table 3, it is clear that feeding animals with a control feed to which an emulsion of MCFAs is added effectively improves the daily weight gain and thus the growth of the animals and in addition also improves feed conversion.

Experiment 4 The present example relates to the effects of a composition according to the invention comprising MCFAs, in particular a mixture of C6, C8 and C10 MCFAs, and a growth promoting element on piglet performance of piglets in the phase 7-20 kg.

Commercial available weaning and starter feeds were used. During the first 2 weeks, a weaning feed was given to the piglets. From the third week till the end of the trial, i. e. at an average weight of 20 kg, the piglets received a starter feed. The trial feeds used are illustrated in table 4. During the whole trial period the piglets were fed ad libitum.

The piglets under study were 120 weaned barrows and sows, with an age of 28 days at weaning. In the stable, 12 pens were present which contained each 10 piglets. For each trial, 3 replicates of 10 piglets were used. Ventilation and heating was automatically controlled. In each pen, 1 drinking nipple was present for water supply.

Piglets were distinguished and weighed individually. They were allocated randomly to the different groups so that the average weight of each group was equal. A total of 120 animals was monitored.

The following parameters were monitored during the trial : - the feed intake per trial group. (measured at the end of the trial) - the weight of the individual animals (was measured at the beginning and at the end of the trial) - the feed conversion ratio per trial group - veterinary treatments and - mortality.

Results of this experiment are indicated in Table 4.

Table 4 Effect of the different feed compositions comprising MFCAs with or without a additional growth promoting element on the performances of pigs Diet Daily growth FCR Number of Mortality g/pig/day Veterinary (%) treatments * Control 340 1. 73 30 6, 6 control + Lentinus edodes 335 1. 74 32 10, 0 control + formic acid 351 1. 69 28 10,0 control + phophorous acid 346 1. 69 30 6, 6 control + Salinomycin 362 1. 70 26 6, 6 control + Avilamycin 365 1. 65 25 3, 3 control + inulin 330 1. 78 32 10 control + Bacillus sp. 345 1. 70 27 6, 6 control + Oregostim 349 1. 71 26 6, 6 control + MCFA's 374 1. 65 15 0, 0 control + Lentinus edodes + MCFAs 368 1. 70 16 3, 3 control + formic acid + MCFAs 371 1. 65 19 0, 0 control + phophorous acid + MCFAs 378 1. 62 14 3, 3 control + Salinomycin + MCFAs 370 1. 65 15 0, 0 control + Avilamycin + MCFAs 366 1. 67 13 3, 3 control + inulin + MCFAs 367 1. 72 12 3, 3 control + Bacillus s. + MCFAs 365 1. 72 11 0, 0 control + Oregostim + MCFAs 365 1.70 14 0,0 (*) the number of veterinary treatments refers to the sum of all treatments performed on the animals during the total period of the trial.

Experiment 5 This example illustrates the influence of a composition according to the present invention on piglet performance.

The present example relates to the effects of a composition according to the invention comprising MCFAs, in particular a mixture of C6, C8 and C10 MCFAs, and a growth promoting element. This composition particularly comprises 30% siliciumdioxide ; 10% aroma, 10% wheat semolina and 50% of a mixture comprising C6, C8 and C10 MCFAs.

A.

In a first example, the effect of the composition as defined above, was tested on pigs in the weaning phase.

The experiment was carried out on pigs from weaning till 2 weeks after weaning. The following feeds were tested during the trial. Feed 1 consisted of a control feed. Feed 2 consisted of a control feed to which 0.2 % of the composition according to the invention was

added. Pig weight and feed intake were monitored. The piglets were weighed on a weekly ~basis. Resurts are in-dicated in Table 5.

Table 5 Effect of the composition according to the invention on pig performance in the weaning phase Feed 1 Feed 2 Age of the piglets (days) 21 21 Trial duration (days) 16 16 Amount of animals 40 40 Mortality 0 0 Average weight start (kg) 7.47 7.53 Average weight end (kg) 11.29 11.90 Weight gain per animal 3. 82 4.37 Average daily gain (g/d) 239 273 Days to obtain 5 kg growth 21 18 Feed intake/group (kg) 101 99 Feed intake/piglet (kg) 5.05 4.95 Daily feed intake/piglet (g) 361 355 Feed conversion ratio 1. 51 1.30 From table 5, it can be concluded that the feed comprising a composition according to the present invention induces a higher daily growth of the pigs, and effectively reduces feed conversion, during the weaning phase.

B. In a second example, the effect of the composition as defined above was tested on pigs in the growing and finishing phase.

The experimental farm consisted of 2 rows, each containing 10 pens. Each pen (2m x 4m) contained 14 pigs. The pigs received feed and water ad libitum. Gilts and boars were mixed.

During the whole experiment the pens were ventilated. The feeds were distributed in such a way, that the average pig weight per feed was similar for all feeds at the beginning of the animal trial, when pig approximately weighted 30 kg.

The following feeds were tested during the trial. Feed 1 consisted of a control feed. Feed 2 consisted of a control feed to which the composition as defined above was added. Control feed to which 0,1 % of the composition was added was administered to the pigs during the growing phase. Control feed to which 0,05 % of the composition was added was administered to the pigs during the finishing phase.

Pig weight and feed intake were monitored. The pigs were weighed individually at 30 kg, 50 kg and 100 kg. Feed uptake per pen was also registered. At the end of the growth phase, the

initial (growers) feed was changed and the pigs were further fed with finisher feed. Feed intake-per= pig was measured-for-the growth phase and for the-finishing phase. Frorri-these data, feed conversion ratios were further calculated. Results are indicated in Table 6.

Table 6 Effect of the composition according to the invention on pig performance Growing phase (30-50 kg) Finishing phase (50-100 kg) Feed 2 Feed 2 (Control + (Control + Feed 1 0. 1% Feed 1 0. 05% composition) composition) Average weight 29, 80 5, 65 29, 94 4, 94 start (kg) Daily growth 575 47. 5 614 47. 2 827 126. 5 824 123. 6 (god Average daily 52.38 53.64 191 180 feed intake (kg/pig) Feed 2.4 2. 3 3.46 3.36 conversion From table 6 it is clear that feed 2 provides a higher growth than feed 1 in the growing phase. Results in this trial indicate that addition of the composition according to the invention to the feed has a positive effect on growth of the pigs, in particular during the grower phase. Also, from table 6 it is clear that supplementation of the composition to the feed resulted over the complete period in a lower feed conversion ratio. In particular, the composition has a positive effect on feed conversion ratio during the finishing phase.

C.

In a third example, the effect of the composition as defined above was tested on the performances of pigs in the growing phase, i. e. from 30-50 kg, and in the finishing phase, i. e. from 50-100 kg.

72 piglets with an average weight of 30 kg at the start of the experiment were used for this experiment. The piglets were housed in 8 pens of 9 piglets each. The experiment had a duration of 91 days. The following feeds were tested during this trial. Feed A consisted of a control feed. Feed B consisted of a control feed to which the composition as defined above was added. Control feed to which 0,1 % of the composition was added was administered to the pigs during the growing phase, i. e. for feeding pigs of 30-50 kg. Control feed to which 0,05 % of the composition was added was administered to the pigs during the finishing phase, i. e.

for feeding pigs of 50-100 kg. Pig weight, mortality and feed intake were monitored. Feed conversion was calculated :-All pigs were weighed individual. Resutts are indicated~iFFTable- 7.

Table 7 Effect of the composition on pig performance Growing phase (30-50 kg) Finishing phase (50-100 kg) Feed B Feed B Feed A (Control + 0.1% Feed A (Control 0,05% composition) composition) Amount of animals 36 36 36 36 Trial duration 25 days 25 days 66 days 66 days Average weight start 30. 02 kg 31. 14 kg 49. 42 51. 56 kg kg Average weight end 49.42 kg 51.56 kg 92.33 97.81 kg kg Mortality 0 0 2/36 3/36 Weight gain per animal 19. 40 kg 20. 42 kg 42. 91 46. 25 kg kg Average daily gain 0. 776 kg 0. 817 kg 0. 650 0. 701 kg kg Average daily feed intake 1. 650 kg 1. 648 kg 1.858 1. 869 kg kg Feed conversion 2.126 2.062 2. 980 2. 818 From table 7 it is clear that the during the growing phase, the average daily gain in weight is 5.3% higher for the group of piglets fed with feed comprising the composition according to the invention, than for the group fed with a control feed. Also, for the group of pigs fed with feed comprising the composition the feed conversion ratio was reduced with 3.10%.

During the finishing phase, the average daily gain in weight is 7.8% higher for the group of piglets fed with feed comprising the composition than for the group fed with a control feed.

Also, for the group of pigs fed with feed comprising the composition the feed conversion ratio was reduced with 5.7%.

In conclusion, from example A is it clear that the feed comprising a composition according to the invention induces a higher daily growth of the pigs, and has a positive effect on feed conversion during the weaning phase. In addition, from examples B and C, it is clear that the feed comprising a composition according to the invention also improves the gain of weight and thus the growth of the pigs, and has a positive effect on feed conversion during the growth and finishing phase.