STABLE GRANULES FOR FEED COMPOSITIONS.

Abstract

The present invention relates to pelleted feed compositions comprising an inner salt layer and an outer hydrophobic layer. The invention further relates to the use of hydrophobic and salt-coated pellets for steam-treated pelleted feed compositions.

Description

STABLE GRANULES FOR FEED COMPOSITIONS FIELD OF INVENTION The present invention relates to pelleted feed compositions comprising an inner salt layer and an outer hydrophobic layer. The invention further relates to the use of hydrophobic and salt-coated pellets for steam-treated pelleted feed compositions. BACKGROUND OF THE INVENTION Animal feed is usually provided as pellets containing the desired ingredients for the animals. This has the advantage that all the necessary ingredients are readily available, the digestibility of the starch fraction is increased, and dust from the ingredients is reduced. During the production of feed pellets, the pellets are treated with high-temperature steam to kill bacteria, such as Salmonella. Often, the active compounds, such as the enzymes present in the feed pellets, are not stable at high temperatures and high humidity, and therefore, a large excess of enzyme is required in the feed pellets. Alternatively, an enzymatic coating can be applied to feed pellets that do not contain enzymes; however, this coating method is Ref. 314180 cumbersome and often incompatible with existing feed plants. One method for improving the stability of the active compound involves providing granules comprising the active compound in the core and a suitable coating agent in the core before steam treatment and pelleting. WO 92 / 12645 describes T-type granules coated with a fat or wax, and the feed components are steam-treated and then pelleted. WO 2006 / 034710 describes enzyme-containing granules coated with a salt coating before pelleting. However, there remains a need to further improve the stability of active compounds, such as enzymes, in pelleted feed products. SUMMARY OF THE INVENTION The invention provides a pelleted feed composition comprising a granule comprising a core and a coating, wherein the core comprises a muramidase and the coating comprises an inner salt layer and an outer hydrophobic layer. The invention further provides a granule comprising a core and a coating, wherein the core comprises a muramidase and the coating comprises an inner salt layer and an outer hydrophobic layer. cz1 znn / Lznz / E / YiAi In a further embodiment, a granule comprising a core and a coating is provided, wherein the core comprises a muramidase and the coating comprises an inner salt layer and an outer hydrophobic layer, wherein the granule comprises at least 75% muramidase with activity retained after steam pelleting compared to the activity before steam pelleting, and wherein the granule further comprises one or more of the following: i. the particle size of the granule is less than 1200 pm, ii. the thickness of the internal salt layer is at least 15 pm, iii. the thickness of the external hydrophobic coating is at least 1 pm, and iv. muramidase is thermolabile. The invention also provides a method for feeding animals, a method for manufacturing a feed composition, a method for improving the stability of muramidase, and a method for improving the stability of muramidase in a paste composition having a moisture content greater than 12%. A further embodiment provides the use of a granule comprising a core comprising a muramidase, an inner salt layer and an outer hydrophobic layer for preparing pelleted feed compositions treated with cz1 znn / Lznz / E / YiAi steam. GENERAL ASPECTS OF THE SEQUENCE LIST SEC. ID NO.: 1 is the DNA sequence of the P242M9 GH25 gene isolated from Acremonium alkalophilum CBS114.92. SEC. ID NO.: 2 is the amino acid sequence deduced from SEC. ID NO.: 1. SEC. ID NO. : 3 is the DNA sequence of a synthetically optimized GH25 gene. SEC. ID NO.: 4 is the amino acid sequence deduced from SEC. ID NO.: 3. DETAILED DESCRIPTION OF THE INVENTION Definitions Constant Humidity: The term constant humidity (in the context of the invention, sometimes abbreviated as HC) of a compound or substance shall be understood as the % RH of atmospheric air in equilibrium with a saturated aqueous solution of the compound in contact with the solid phase of the compound, all confined within an enclosed space at a given temperature. This definition is in accordance with Handbook of Chemistry and Physics, CRC Press, Inc., Cleveland, USA, 58th edition, p. E46, 1977-1978. Accordingly, HC20 °C = 50% for a compound means that air with a humidity of 50% will be in equilibrium with a saturated aqueous solution of the compound at 20 °C. Consequently, the term constant humidity is a measure of the hygroscopic properties of a compound. Dust: The term dust in connection with granules or powders refers to the tendency of a granule or powder, when handled, to release fine airborne particles. Granule or powder dust is routinely measured in industry and can be measured using several different techniques. Well-known methods for measuring enzyme dust, for example, include the decantation test and the Heubach type 1 test. In the decantation test, enzyme granules are placed on a porous glass filter inside a tall glass tube and fluidized with a constant stream of dry air for a fixed period of time. In the Heubach test, granules are placed in a small cylindrical steel chamber equipped with a paddle stirrer and steel balls; the granules are pushed by the stirrer and balls, while a stream of dry air is filtered through the chamber.In both tests, the dust removed from the particles by the air stream is captured on a fiberglass filter for subsequent weight measurement and activity determination. Further details of these tests can be found, for example, in Enzymes In Detergency, ed. Jan H. van Ee, et al., Chpt. 15, pp. 310-312 (Marcel Dekker, Inc., New York, NY (1997)), and the references cited in this invention. Muramidase GH25: The term muramidase GH25 is used for muramidases belonging to the GH25 family. The GH25 family is a classification of enzymes according to Henrissat's classification of the glycosyl hydrolases family (Henrissat B., A classification of glycosyl hydrolases based on aminoacid sequence similarities. Biochem. J. 280:309-316(1991); Henrissat B., Bairoch A. New families in the classification of glycosyl hydrolases based on amino-acid sequence similarities. Biochem. J. 293:781-788(1993); Henrissat B., Bairoch A. Updating the sequence-based classification of glycosyl hydrolases. J. 316:695-696(1996); In addition to GH25, other families of hydrolase enzymes with lysozyme activity (EC 3.2.1.17) are GH22, GH23 and GH24. Hydrogenated: The term hydrogenated is used for the saturation of unsaturated carbohydrate chains, for example, in triglycerides, in which the carbon=carbon double bonds are converted into carbon-carbon single bonds. Feed composition: Feed composition is the nutritionally complete composition of cereals, cereal products and optional supplements in ground form, for example comprising wheat, corn, ... which has not been pelleted or conditioned. Particle size: The particle size of the granule cz / znn / Lznz / E / Yii refers to the average mass diameter of the granules. Composition of pelleted feed: The term composition of pelleted feed is intended to mean the composition of feed after pelleting and conditioning, i.e., the feed pellets with which the animals will be fed. % RH: The term % RH refers to the relative humidity of the air. 100% RH is air saturated with water vapor at a given temperature, and % RH reflects the percentage of moisture saturation in the air. Solution: A solution is defined as a homogeneous mixture of two or more substances. Suspension: A suspension is defined as fine particles suspended in a liquid. Introduction Enzymes, such as muramidase, in a feed product pelleted from a mixture composition having a moisture content of, for example, 13 to 15%, tend to have lower stability than in feed products from mixture compositions with lower moisture content. It has been surprisingly discovered with the invention that the stability of muramidase generally increases when the muramidase is composed of granules comprising an inner salt layer and an outer hydrophobic layer. Furthermore, it has been surprisingly discovered that with the invention, the stability of muramidase is also increased for muramidases pelleted from mixture compositions with a moisture content above 11%, such as 13 to 15%.Therefore, the stability of muramidase in feed exposed to steam treatment is improved compared to the stability of steam-treated muramidase not contained in the granules of the invention. An additional advantage of the invention is that the granules release only a small amount of dust, and their shelf life is maintained. The granule When referring to the granule of the present invention, it can be either a single granule or several granules. The granule of the present invention is particularly well-suited to steam pelleting and as part of a steam-treated pelleted feed composition. The invention comprises a core and a coating, wherein the core comprises a muramidase and the coating comprises an inner salt layer and an outer hydrophobic layer. The suitable particle sizes of the granule of the present invention have been determined to be from 50 to 2000 µm, more particularly from 100 to 1500 µm. In one embodiment of the invention, the particle size of the granule is greater than 250 µm. In a further embodiment of the invention, the particle size is less than 1200 µm. In yet another embodiment, the particle size is between 250 and 1200 µm. In another embodiment of the present invention, the particle size of the finished granule is from 250 to 900 µm. In yet another embodiment of the present invention, the average particle size of the finished granule is from 500 to 700 µm. In yet another embodiment of the present invention, the particle size of the finished granule is from 600 to 1200 µm. In another embodiment of the present invention, the particle size of the finished granule is 600 to 900 pm. The core The core comprises a muramidase, such as a muramidase GH25, in the form of concentrated dry matter. The core can be 1. a homogeneous mixture of enzymes that includes one or more muramidases, or 2. an inert particle with muramidase and optionally more enzymes applied to it, or 3. a homogeneous mixture of enzymes including one or more muramidases and binder-acting materials coated with one or more muramidases. The particle size of the core of the present invention is, in a particular embodiment, from 20 to 1900 pm. C717PΠ / ί7PΠ7 / E / YΙΛΙ In a more particular embodiment of the present invention, the particle size of the core is from 50 to 1400 pm. In a still more particular embodiment of the present invention, the particle size of the core is from 150 to 1100 pm. In an embodiment of the most particularity of the present invention, the particle size of the core is from 250 to 1200 pm. In instances where the core comprises an inert particle, the inert particle may be water-soluble or water-insoluble, for example, starch, such as cassava or wheat starch; or a sugar (such as sucrose or lactose), or a salt (such as sodium chloride or sodium sulfate). Suitable inert particle materials of the present invention include inorganic salts, sugars, sugar alcohols, small organic molecules such as organic acids or salts, minerals such as clays or silicates, or a combination of two or more of these. The inert particles may be produced by various granulation techniques, including crystallization, precipitation, drum coating, fluidized bed coating, fluidized bed agglomeration, centrifugal spraying, extrusion, agglomeration, spheronization, size reduction methods, drum granulation, and / or high-shear granulation. In instances where the core comprises one or more C717ΠΠ / ίΖΠΖ / E / YΙΛΙ Binders, the binders can be synthetic polymers, such as, for example, a vinyl polymer, polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyvinyl acetate, polyacrylate, polymethacrylate, polyacrylamide, polysulfonate, polycarboxylate, and copolymers thereof, waxes, including fats, fermentation broth, carbohydrates, salts, or polypeptides. In one particular embodiment, the binder is a polypeptide. The polypeptide can be selected from gelatin, collagen, casein, polyaspartic acid, and polyglutamic acid. In another particular embodiment, the binder is a cellulose derivative, such as hydroxypropylcellulose, methylcellulose, or CMC. A suitable binder is a carbohydrate binder, such as dextrin, for example, Glucidex 21D or Avedex W80. In one form, the nucleus may comprise a salt. The salt may be an inorganic salt, for example, a sulfate, sulfite, phosphate, phosphonate, nitrate, chloride, or carbonate salt, or salts of simple organic acids (fewer than 10 carbon atoms, for example, 6 or fewer carbon atoms) such as citrate, malonate, or acetate. Examples of cations in these salts are alkali or alkaline earth metal ions, the ammonium ion, or ions of metals from the first transition series, such as sodium, potassium, magnesium, calcium, zinc, or aluminum. Examples of anions include chloride, iodide, sulfate, sulfite, bisulfite, C717PΠ / ί7P7 / E / YΙΛΙ thiosulfate, phosphate, monobasic phosphate, dibasic phosphate, hypophosphite, dihydrogen pyrophosphate, carbonate, bicarbonate, metasilicate, citrate, malate, maleate, malonate, succinate, lactate, formate, acetate, butyrate, propionate, benzoate, tartrate, ascorbate, or gluconate. In particular, salts of alkali or alkaline earth metals of sulfate, sulfite, phosphate, phosphonate, nitrate, chloride, or carbonate, or salts of simple organic acids such as citrate, malonate, or acetate, may be used. Specific examples include NaH₂PO₄, Na₂HPO₄, Na₃PO₄, (NH₄)H₂PO₄, K₂HPO₄, KH₂PO₄, Na₂SO₄, K₂SO₄, KHSO₄, ZnSO₄, MgSO₄, CuSO₄, Mg(NO₃)₂, (NH₄)₂SO₄, sodium borate, magnesium acetate, and sodium citrate. The salt in the particle core may also be a hydrated salt, that is, a hydrated crystalline salt with one or more water molecules attached from crystallization, as described in WO 99 / 32595.Examples of hydrated salts include magnesium sulfate heptahydrate (MgSCy(7H2O)), zinc sulfate heptahydrate (ZnSCg(7H2O)), dibasic sodium phosphate heptahydrate (Na2HPO4(7H2O)), magnesium nitrate hexahydrate (Mg(NO3)2(6H2O)), sodium borate decahydrate, sodium citrate dihydrate, and magnesium acetate tetrahydrate. In one embodiment, the core and / or the internal salt layer may comprise a moisture-absorbing compound. The moisture-absorbing compound acts as a buffer capable of decreasing water activity by reducing the free water in contact with the muramidase in the granule. If the moisture-absorbing compound is added to the core, it is important that there be an excessive buffering capacity to remove the water present after the application of the internal salt layer. In one embodiment, the moisture-absorbing compound has a water uptake of more than 3%, such as more than 5%, or more than 10%. Water uptake has been found to be at equilibrium at 25°C and 70% relative humidity after one week. The amount of moisture-absorbing compound added to the granule is greater than 1%, greater than 2%, greater than 5%, or greater than 10% w / w of the granule. The moisture-absorbing compound can be either organic or inorganic and can be selected, but not limited to, from the group consisting of flour, starch, corn products, cellulose, and silica gel. The granule may include additional materials such as processing aids, fillers, fiber materials, stabilizing agents, solubilizing agents, suspending agents, viscosity regulators, lightweight spheres, plasticizers, salts, lubricants, and fragrances. Processing aids may be supplied, for example, as a spray and may be, for example, CaCO3, talc, and / or kaolin. Suitable fillers are water-soluble and / or water-insoluble inorganic salts such as finely powdered alkali sulfate, alkali carbonate, and / or alkali chloride; clays such as kaolin (e.g., SPESWHITE™, china clay), bentonites, talc, zeolites, chalk, calcium carbonate, and / or silicates. Common fillers are disodium sulfate and calcium lignosulfonate. Stabilizing or protective agents are those conventionally used in the field of granulation.Stabilizing or protective agents can fall into several categories: alkaline or neutral materials, reducing agents, antioxidants, and / or salts of first transition series metal ions. Each of these can be used in conjunction with other protective agents from identical or different categories. Examples of alkaline protective agents include alkali metal silicates, carbonates, or bicarbonates. Examples of protective agents include sulfite, thiosulfite, thiosulfate, or MnSCp salts, while examples of antioxidants include methionine, butylated hydroxytoluene (BHT), or butylated hydroxyanisole (BHA). In particular, stabilizing agents can be thiosulfate salts, for example, sodium thiosulfate or methionine.Other examples of useful stabilizers include gelatin, urea, sorbitol, glycerol, casein, polyvinylpyrrolidone (PVP), hydroxypropyl methylcellulose (HPMC), carboxymethylcellulose (CMC), hydroxyethylcellulose (HEC), skimmed milk powder, and / or edible oils such as soybean oil or canola oil. The specific stabilizing agents in feed pellets are a source of lactic acid or starch. A preferred source of lactic acid is fermented corn liquor. It is also known in the art that enzyme substrates, such as starch, lipids, proteins, etc., can act as enzyme stabilizers. Muramidase: A muramidase for use in the present invention may be any muramidase, a combination of two or more muramidases, or a combination of any muramidase and one or more additional enzymes. Accordingly, when reference is made to a muramidase in general, it shall be understood to include a muramidase, a combination of two or more muramidases, or a combination of a muramidase and one or more additional enzymes. A muramidase is an O-glycosyl hydrolase, which has lysozyme activity and therefore catalyzes the hydrolysis of the glycosidic bond between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate entity. Lysozymes dissociate the glycosidic bond between certain residues in mucopolysaccharides and mucopeptides of bacterial cell walls, such as the 1,4-beta linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues in peptidoglycan and between N-acety-1-D-glucosamine residues in chytodextrins, resulting in bacteriolysis. Muramidase belongs to the EC 3.2.1.17 enzyme class. Muramidase variants (produced, for example, by recombinant techniques) shall be understood to be included within the meaning of the term muramidase. Examples of such muramidase variants are described, for example, in documents WO 2013 / 076253, WO 2018 / 113743 and WO 2018 / 113745. In one embodiment, the muramidase for use in the invention is a GH25 muramidase. In one embodiment, the muramidase for use in the invention has the ability to lyse bacterial cell walls. In one embodiment, the muramidase for use in the invention has improved lysozyme activity a) compared to the lysozyme activity of hen egg white lysozyme (HEWL) as determined by either i) Method for the determination of lysozyme activity against Micrococcus lysodeikticus as determined according to the turbidity test described in Example 4 of WO 2013 / 076253 and ii) Method for the determination of lysozyme activity against Lactobacillus johnsonii as determined by the Method for the determination of lysozyme activity against Lactobacillus johnsonii as described in Example 56 of WO 2018 / 113745.In one embodiment, the muramidase for use in the invention has lysozyme activity against peptidoglycans found in the cell walls of Micrococcus lysodeikticus as determined according to the turbidity test described in Example 4 of WO 2013 / 076253. In another embodiment, the muramidase for use in the invention has lysozyme activity against Lactobacillus johnsonii as determined by the Method for the Determination of Lysozyme Activity against Lactobacillus johnsonii as described in Example 56 of WO 2018 / 113745. In one embodiment, the muramidase for use in the invention is an isolated polypeptide having lysozyme activity and is selected from the group consisting of: a. a polypeptide having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity with respect to the mature polypeptide of SEC. ID NO.: 2 or the mature polypeptide of SEC. ID NO.: 4; b. a polypeptide encoded by a polynucleotide having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity with the mature polypeptide coding sequence of SEC. ID NO.: 1 or with the mature polypeptide coding sequence of cz j znn / Lznz / E / YiAi SEC. ID NO.: 3; c. a polypeptide encoded by a polynucleotide that hybridizes under medium-high astringency conditions with the coding sequence of the mature polypeptide of SEC. ID. NO. : 1 or SEC. ID. NO. : 3 or the full length complement thereof; d. a variant of the mature polypeptide of SEC. ID NO.: 2 or SEC. ID NO.: 4 comprising a substitution, deletion and / or insertion at one or more positions (e.g., several); and e. a fragment of the polypeptide of (a), (b), (c) or (d) that has lysozyme activity. In one embodiment, the muramidase for use in the invention is selected from polypeptides comprising or consisting of the mature polypeptide of SEC. ID NO.: 2 or SEC. ID NO.: 4. In one embodiment, the muramidase for use in the invention is an isolated polypeptide mentioned in WO 2018 / 113743 and is selected from the group consisting of: (a) a polypeptide having at least 90% sequence identity with the polypeptide of SEC. ID NO.: 3 of document WO 2018 / 113743; (b) a polypeptide having at least 80% sequence identity with the polypeptide of SEC. ID NO.: 6 of document WO 2018 / 113743; (c) a polypeptide having at least 80% of C717ΠΠ / L7n7 / E / YIAI sequence identity with the polypeptide of SEC. ID NO.: 9 of document WO 2018 / 113743; (d) a polypeptide having at least 80% sequence identity with the polypeptide of SEC. ID NO.: 12 of document WO 2018 / 113743; (e) a polypeptide having at least 80% sequence identity with the polypeptide of SEC. ID NO.: 15 of document WO 2018 / 113743; (f) a polypeptide having at least 80% sequence identity with the polypeptide of SEC. ID NO.: 18 of document WO 2018 / 113743; (g) a polypeptide having at least 80% sequence identity with the polypeptide of SEC. ID NO.: 21 of document WO 2018 / 113743; (h) a polypeptide having at least 80% sequence identity with the polypeptide of SEC. ID NO.: 24 of document WO 2018 / 113743; (i) a polypeptide having at least 80% sequence identity with the polypeptide of SEC. ID NO.: 27 of document WO 2018 / 113743; (j) a polypeptide having at least 80% sequence identity with the polypeptide of SEC. ID NO.: 30 of document WO 2018 / 113743; (k) a polypeptide having at least 80% sequence identity with the polypeptide of SEC. ID NO.: cz i znn / Lznz / Ε / γΐΛΐ from document WO 2018 / 113743; 1) a polypeptide having at least 83% sequence identity with the polypeptide of SEC. ID NO.: 38 of document WO 2018 / 113743; In one embodiment, the muramidase for use in the invention is an isolated polypeptide mentioned in WO 2018 / 113745 and is selected from the group consisting of: (a) a polypeptide having at least 80% sequence identity with a polypeptide selected from the group consisting of SEC. ID NO.: 3 of WO 2018 / 113745, SEC. ID NO.: 9 of WO 2018 / 113745, SEC. ID NO.: 12 of WO 2018 / 113745, SEC. ID NO.: 15 of WO 2018 / 113745, SEC. ID NO.: 18 of WO 2018 / 113745, SEC. ID NO.: 21 of WO 2018 / 113745, SEC. ID NO.: 24 of WO 2018 / 113745, SEC. ID NO.: 27 of WO 2018 / 113745, SEC. ID NO.: 33 of document WO 2018 / 113745, SEC. ID NO.: 36 of document WO 2018 / 113745, SEC. ID NO.: 42 of document WO 2018 / 113745, SEC. ID NO.: 45 of document WO 2018 / 113745, SEC. ID NO.: 48 of document WO 2018 / 113745, SEC. ID NO.: 51 of document WO 2018 / 113745, SEC. ID NO.: 54 of document WO 2018 / 113745, SEC. ID NO.: 57 of document WO 2018 / 113745, SEC. ID NO.: 60 of document WO 2018 / 113745, SEC. ID NO.: 63 of document WO 2018 / 113745, SEC. ID NO.: 66 of document WO 2018 / 113745, SEC. ID NO.: 69 of document WO. C71ΖΠΠ / ίΖΠΖ / Ε / ΥΙΛΙ 2018 / 113745, SEC. ID NO.: 75 of document WO 2018 / 113745, SEC. ID NO.: 80 of document WO 2018 / 113745, SEC. ID NO.: 83 of document WO 2018 / 113745, SEC. ID NO.: 86 of document WO 2018 / 113745, SEC. ID NO.: 98 of document WO 2018 / 113745, SEC. ID NO.: 101 of document WO 2018 / 113745, SEC. ID NO.: 104 of document WO 2018 / 113745, SEC. ID NO.: 107 of document WO 2018 / 113745, SEC. ID NO.: 116 of Document WO 2018 / 113745, SEC. ID NO.: 119 of Document WO 2018 / 113745, SEC. ID NO.: 122 of Document WO 2018 / 113745, SEC. ID NO.: 125 of Document WO 2018 / 113745, SEC. ID NO.: 128 of Document WO 2018 / 113745, SEC. ID NO.: 131 of Document WO 2018 / 113745, SEC. ID NO.: 134 of Document WO 2018 / 113745, SEC. ID NO.: 137 of Document WO 2018 / 113745, SEC. ID NO.: 140 of document WO 2018 / 113745, SEC. ID NO.: 143 of document WO 2018 / 113745, SEC. ID NO.: 146 of document WO 2018 / 113745, SEC. ID NO.: 149 of document WO 2018 / 113745, the SEC. ID NO.: 152 of document WO 2018 / 113745, SEC. ID NO.: 155 of document WO 2018 / 113745, SEC. ID NO.: 158 of document WO 2018 / 113745, SEC. ID NO.: 221 of document WO 2018 / 113745, SEC. ID NO.: 224 of document WO 2018 / 113745, SEC. ID NO.: 227 of document WO 2018 / 113745, SEC. ID NO.: 230 of document WO 2018 / 113745 and SEC. ID NO.: 233 of document WO 2018 / 113745;. (b) a polypeptide having at least 84% sequence identity with a polypeptide selected from the group consisting of SEC. ID NO.: 6 of WO 2018 / 113745, SEO. ID NO.: 30 of WO 2018 / 113745 and SEC. ID NO.: 72 of WO 2018 / 113745; (c) a polypeptide having at least 86% sequence identity with the polypeptide of SEC. ID NO.: 89 of WO 2018 / 113745; (d) a polypeptide having at least 82% sequence identity with a polypeptide selected from the group consisting of SEC. ID NO.: 92 of WO 2018 / 113745, SEC. ID NO.: 95 of WO 2018 / 113745 and SEC. ID NO.: 110 of WO 2018 / 113745; and (e) a polypeptide having at least 81% sequence identity with the polypeptide of SEC. ID NO.: 113 of WO 2018 / 113745. The present invention is particularly suitable for thermolabile muramidases. The term thermolabile, as applied in the context of certain muramidases, refers to the melting temperature, Tf, as determined by differential scanning calorimetry (DSC) at pH 5.5. For a thermolabile muramidase, Tf is less than 100 °C. In particular embodiments, Tf is less than 90 °C, such as less than 80 °C, less than 70 °C, or even less than 60 °C. The determination of Tf by DSC is carried out at various pH values ​​using VP-DSC. C717ΠΠ / ίΖΠΖ / Ε / ΥΙΛΙ MicroCal. Scans are performed at a constant scan rate of 1.5 °C / min from 20 to 90 °C. Prior to DSC, muramidase is desalted using NAP-5 columns (Pharmacia) equilibrated in appropriate buffers (e.g., 0.2 M quinine-HCl, pH 2.5 or 3.0; 0.1 M sodium acetate, pH 5.5; 0.1 M Tris-HCl, pH 7.0). Data processing can be performed using MicroCal Origin software. DSC measurements are performed as described in WO 2003 / 66847, which is incorporated herein by reference. In a particular embodiment of the present invention, the muramidase in the granules of the present invention is thermolabile. In a particular embodiment of the present invention, the muramidase in the pelleted feed composition granules is thermolabile. In a particular embodiment of the present invention, the muramidase in the granules to be used for pelleted feed compositions is thermolabile. The coating The particle core is coated with an inner salt layer surrounding the core, an outer hydrophobic layer surrounding the inner salt layer, and optionally one or more additional coating layers. The inner salt layer The internal salt layer can in a particular way C717ΠΠ / ί7Π7 / E / YΙΛΙ of the present invention contribute between 20 and 99% w / w of the granule, such as between 20-70% w / w, 30-60% w / w, 40-60% w / w, or 50-60% w / w of the granule. In one embodiment, the internal salt layer comprises at least 60% w / w, e.g., 65% w / w or 70% w / w of salt, which may be at least 75% w / w, e.g., at least 80% w / w, at least 85% w / w, e.g., at least 90% w / w, at least 95% w / w, or even at least 99% w / w of salt. In a particular embodiment of the present invention, the amount of salt in the internal salt layer of the granule constitutes at least 40% w / w of the internal salt layer. In a particular embodiment of the present invention, the amount of salt in the internal salt layer of the granules in the feed composition, such as, for example, steam-treated feed compositions, constitutes at least 40% w / w of the internal salt layer. In a particular embodiment of the present invention, the amount of salt in the inner salt layer of the granules to be used for feed compositions, such as, for example, steam-treated feed compositions, constitutes at least 40% w / w of the inner salt layer. In another particular embodiment of the present invention, the amount of salt in the internal salt layer of the granule constitutes at least 50% w / w of the internal salt layer. In a particular embodiment of the present invention, the amount of salt in the internal salt layer of the granules in the feed composition, such as, for example, steam-treated feed compositions, constitutes at least 50% w / w of the internal salt layer. In a particular embodiment of the present invention, the amount of salt in the inner salt layer of the granules to be used for feed compositions, such as, for example, steam-treated feed compositions, constitutes at least 50% w / w of the inner salt layer. In a particular embodiment of the present invention, the amount of salt in the internal salt layer of the granule constitutes at least 60% w / w of the internal salt layer. In a particular embodiment of the present invention, the amount of salt in the internal salt layer of the granules in the feed composition, such as, for example, steam-treated feed compositions, constitutes at least 60% w / w of the internal salt layer. In a particular embodiment of the present invention, the amount of salt in the inner salt layer of the granules to be used for feed compositions, such as, for example, steam-treated feed compositions, constitutes at least 60% w / w of the inner salt layer. To provide acceptable protection, the internal salt layer preferably has a certain thickness. In one particular embodiment of the present invention, the internal salt layer has a thickness of at least 15 µm. In a more particular embodiment, the thickness of the internal salt layer is at least 22 µm. In a still more particular embodiment, the total thickness of the internal salt layer is at least 30 µm. In a most particular embodiment, the total thickness of the internal salt layer is at least 37 µm. In a most particular embodiment, the total thickness of the internal salt layer is at least 45 µm. In a most particular embodiment, the total thickness of the internal salt layer is at least 52 µm. In one particular embodiment of the present invention, the thickness of the internal salt layer is less than 100 µm. In a most particular embodiment, the thickness of the internal salt layer is less than 60 µm.In an even more particular modality, the total thickness of the internal salt layer is less than 40 pm. In one particular embodiment of the present invention, the thickness of the internal salt layer of the granule of the present invention is at least 30 µm. In another particular embodiment of the present invention, the thickness of the internal salt layer of the granule of the present invention is at least 37 µm. In yet another particular embodiment of the present invention, the thickness of the internal salt layer of the granule of the present invention is at least 45 µm. In a particular embodiment of the present invention, the thickness of the internal salt layer of the granules to be used for feed composition, such as, for example, C717РР / ЯЖРЖ / E / ХЙЛЙ steam-treated pelleted feed composition, and of at least 30 pm. In another particular embodiment of the present invention, the thickness of the internal salt layer of the granules to be used for the feed composition, such as, for example, the steam-treated pelleted feed composition, is at least 37 pm. In yet another particular embodiment of the present invention, the thickness of the internal salt layer of the granules to be used for the feed composition, such as, for example, the steam-treated pelleted feed composition, is at least 45 pm. In one particular embodiment of the present invention, the thickness of the internal salt layer of the granules to be used for feed composition, such as, for example, steam-treated pelleted feed composition, is at least 30 µm. In another particular embodiment of the present invention, the thickness of the internal salt layer of the granules to be used for feed composition, such as, for example, steam-treated pelleted feed composition, is at least 37 µm. In yet another particular embodiment of the present invention, the thickness of the internal salt layer of the granules to be used for feed composition, such as, for example, steam-treated feed composition, is at least 45 µm. In one embodiment, the coated granule is a granule according to document WO 01 / 25412, where the ratio between the C717ΠΠ / ί7Π7 / E / YΙΛΙ The coated granule diameter and core unit diameter (abbreviated DG / DC) for this type of granule is at least 1.1, particularly at least 1.5, more particularly at least 2, more particularly at least 2.5, more particularly at least 3, with the maximum particularity at least 4. DG / DC is, however, particularly less than approximately 100, particularly less than 50, more particularly less than 25, and with the maximum particularity less than 10. A particular range of DG / DC is from approximately 4 to approximately 6. Accordingly, for such granules the thickness of the internal salt layer should be at least 25 pm. A particular thickness is at least 50 pm, such as at least 75 pm, at least 100 pm, at least 150 pm, at least 200 pm, at least 250 pm, or particularly at least 300 pm. The thickness of this type of internal salt layer is usually below 800 pm.A particular thickness is less than 500 pm such as less than 350 pm, less than 300 pm, less than 250 pm, less than 200 pm, less than 150 pm or particularly less than 80 pm. The inner salt layer must encapsulate the core unit by forming a substantially continuous layer, i.e., an inner salt layer with few or no holes, so that the encapsulated core unit has few or no uncoated areas. The inner salt layer must be particularly homogeneous in thickness. The salt to be added is preferably in the form of C717ΠΠ / ί7Π7 / Ε / ΥΙΛΙ a salt solution or a salt suspension in which the fine particles are less than 5 pm, such as less than 1 pm. In one particular embodiment of the present invention, a salt solution is preferred as the inner salt layer. However, if the salts used have low solubility, a salt suspension may be preferable to a solution, allowing for a higher percentage of salt to be added per liter of liquid to the granules. In one particular embodiment of the present invention, the inner salt layer is prepared according to the coating described in WO 03 / 55967. Regarding the salt in the inner salt layer, this can be either a particular salt or a mixture of salts. The salt used can be an inorganic salt, for example, sulfate, sulfite, phosphate, phosphonate, nitrate, chloride, or carbonate salts, or salts of simple organic acids (fewer than 10 carbon atoms, for example, 6 or fewer carbon atoms) such as citrate, malonate, or acetate. Examples of cations in these salts include alkali or alkaline earth metal ions, the ammonium ion, or ions of metals from the first transition series, such as sodium, potassium, magnesium, calcium, zinc, or aluminum. Examples of anions include chloride, bromide, iodide, sulfate, sulfite, bisulfite, thiosulfate, phosphate, monobasic phosphate, dibasic phosphate, hypophosphite, dihydrogen pyrophosphate, tetraborate, borate, carbonate, bicarbonate, metasilicate, citrate, malate, maleate, malonate, succinate, lactate, formate, acetate, butyrate, propionate, benzoate, tartrate, ascorbate, or gluconate.Specifically, salts of alkali or alkaline earth metals such as sulfate, sulfite, phosphate, phosphonate, nitrate, chloride, or carbonate, or salts of simple organic acids such as citrate, malonate, or acetate, can be used. Specific examples include NaH₂PO₄, Na₂HPO₄, NasPCg, (NH₄)H₂PO₄, K₂HPO₄, KH₂PO₄, Na₂SO₄, K₂SO₄, KHSO₄, ZnSO₄, MgSO₄, CuSO₄, Mg(NO₃)₂, (NH₄)₂SO₄, sodium borate, magnesium acetate, and sodium citrate. Salt can also be a hydrated salt, that is, a crystalline salt hydrated with one or more water molecules attached from crystallization, as described in WO 99 / 32595. Examples of hydrated salts include magnesium sulfate heptahydrate (MgSO4(7H2O)), zinc sulfate heptahydrate (ZnSO4(7H2O)), dibasic sodium phosphate heptahydrate (Na2HPO4(7H2O)), magnesium nitrate hexahydrate (Mg(NO3)2(6H2O)), sodium borate decahydrate, sodium citrate dihydrate, and magnesium acetate tetrahydrate. In one embodiment of the present invention, the inner salt layer does not comprise a hydrated salt. In a particular embodiment of the present invention, the inner salt layer does not comprise a salt comprising more than four molecules of water at 50 °C. In a particular embodiment of the present invention, specific examples of suitable salts of the invention are NaCl (CH20°C=76%), Na2CO3 (CH20°C=92%), NaNO3 (CH20°C=73%), Na2HPO4 (CH20°C=95%), Na3PO4 (CH25°C=92%), NH4Cl (CH20°C=79.5%), (NH4)2HPO4 (CH20°C=93.0%), NH4H2PO4 (CH20°C=93.1%), (NH4)2SO4 (CH20°C=81.1%), KCl (CH20°C=85%), K2HPO4 (CH20°C=92%), KH2PO4 (CH20°C=96.5%), KNO3 (CH20°C=93.5%). Na2SO4(CH20°c=93%), K2SO4(CH20°c=98%), KHSO4(CH20c=86%), MgSO4(CH20°c=90%), ZnSO4(CH20°c=90%) and sodium citrate (CH25°c=86%). In a particular embodiment of the present invention, the salt is selected from the group consisting of NaCl, Na2CO3, NaNO3, Na2HPO4, Na3PO4, NH4C1, (NH4)2HPO4, NH4H2PO4, (NH4)2SO4, KC1, K2HPO4, KH2PO4, KNO3, Na2SO4, K2SO4, KHSO4, MgSO4, ZnSO4, NaCl and sodium citrate or mixtures thereof. In a more particular embodiment of the present invention, the salt is selected from the group consisting of NaCl, Na2CO3, NaNO3, Na2HPO4, Na3PO4, NHzCl, (NH4)2HPO4, NH4H2PO4, (NH4)2SO4, KC1, K2HPO4, KH2PO4, KNO3, Na2SO4, K2SO4, KHSO4, NaCl and sodium citrate or mixtures thereof. In a particular embodiment of the present invention, the salt comprising the inner salt layer of the granule of the present invention is selected from the group consisting of NaCl, Na2CO3, NaNO3, Na2HPO4, Na3PO4, NH4C1, (NH4)2HPO4, NH4H2PO4, (NH4)2SO4, KC1, K2HPO4, KH2PO4, KNO3, Na2SO4, K2SO4, KHSO4, MgSO4, ZnSO4, NaCl and sodium citrate or mixtures thereof. C717ΠΠ / L7n7 / E / YIAI In a particular embodiment of the present invention, the salt comprising the internal salt layer of the pelleted feed composition treated with steam is selected from the group of NaCl, Na2CO3, NaNOs, Na2HPO4, NasPCg, NHzCl, (NH4)2HPO4, NH4H2PO4, (NH4)2SO4, KC1, K2HPO4, KH2PO4, KNO3, Na2SO4, K2SO4, KHSO4, MgSO4, ZnSO4, NaCl and sodium citrate or mixtures thereof. In a particular embodiment of the present invention, the salt comprising the inner salt layer of the granules to be used for steam-treated pelleted feed compositions is selected from the group of NaCl, Na2CO3, NaNO3, Na2HPO4, Na3PO4, NH4Cl, (NH4)2HPO4, NH4H2PO4, (NH4)2SO4, KCl, K2HPO4, KH2PO4, KNO3, Na2SO4, K2SO4, KHSO4, MgSO4, ZnSO4, NaCl and sodium citrate or mixtures thereof. The outer hydrophobic layer In one particular embodiment of the present invention, the outer hydrophobic layer can contribute between 1 and 10% w / w of the granule, or between 1-5% w / w, or between 2-3% w / w of the granule. In one embodiment, the outer hydrophobic layer contributes approximately 2% w / w of the granule. In another embodiment, the outer hydrophobic layer contributes approximately 3% w / w of the granule. In a particular embodiment of the present invention, the amount of hydrophobic coating material in the outer hydrophobic layer of the granule constitutes at least 60% w / w of cz 1 znn / Lznz / E / γALA the outer hydrophobic layer. In a particular embodiment of the present invention, the amount of hydrophobic coating material in the outer hydrophobic layer of the granules in the feed composition, such as, for example, steam-treated feed compositions, constitutes at least 60% w / w of the outer hydrophobic layer. In a particular embodiment of the present invention, the amount of hydrophobic coating material in the outer hydrophobic layer to be used for feed compositions, such as, for example, steam-treated feed compositions, constitutes at least 60% w / w of the outer hydrophobic layer. To provide acceptable protection, the outer hydrophobic layer preferably has a certain thickness. In one particular embodiment of the present invention, the outer hydrophobic layer has a thickness of at least 1 µm. In a more particular embodiment, the thickness of the outer hydrophobic layer is at least 1.5 µm. In a still more particular embodiment, the total thickness of the outer hydrophobic layer is at least 2 µm. In a most particular embodiment, the total thickness of the outer hydrophobic layer is at least 4 µm. In a most particular embodiment, the total thickness of the outer hydrophobic layer is at least 7 µm. In one particular embodiment of the present invention, the thickness of the outer hydrophobic layer is less than 10 µm. In a more particular embodiment, the thickness of the outer hydrophobic layer is less than 7 µm. In an even more particular modality, the total thickness of the outer hydrophobic layer is less than 4 pm. In one particular embodiment of the present invention, the thickness of the outer hydrophobic layer of the granule of the present invention is at least 1.5 µm. In another particular embodiment of the present invention, the thickness of the outer hydrophobic layer of the granule of the present invention is at least 2 µm. In one particular embodiment of the present invention, the thickness of the outer hydrophobic layer of the granules to be used for the feed composition, such as, for example, steam-treated pelleted feed composition, is at least 1.5 µm. In another particular embodiment of the present invention, the thickness of the outer hydrophobic layer of the granules to be used for the feed compositions, such as, for example, steam-treated pelleted feed composition, is at least 2 µm. In one particular embodiment of the present invention, the thickness of the outer hydrophobic layer of the granules to be used for feed compositions, such as, for example, steam-treated pelleted feed compositions, is at least 1.5 µm. In another particular embodiment of the present invention, the thickness of the outer hydrophobic layer of the granules to be used for feed compositions, such as, for example, steam-treated pelleted feed compositions, is at least 2 µm. The outer hydrophobic layer must encapsulate the inner salt layer by forming a substantially continuous layer, i.e., as an outer hydrophobic layer with few or no pores, so that the encapsulating inner salt layer has few or no uncoated areas. In a preferred embodiment, the outer hydrophobic layer should be homogeneous in thickness. With regard to the hydrophobic coating material in the outer hydrophobic layer, it can be a particular hydrophobic coating material or a mixture of hydrophobic coating materials. The hydrophobic coating material may include oils and / or waxes, including, but not limited to, hydrogenated vegetable oils such as hydrogenated castor oil, hydrogenated palm kernel oil, hydrogenated palm oil, hydrogenated cottonseed oil, hydrogenated soybean seed oil and / or hydrogenated rapeseed oil, a mixture of hydrogenated and non-hydrogenated vegetable oil, 12-hydroxystearic acid, microcrystalline wax such as Cerit HOT, and high melting point paraffin waxes such as Mekon White. C717ΠΠ / ί7Π7 / E / YΙΛΙ Other hydrophobic coating materials included in the invention are combinations with water-immiscible liquids or low-melting-point hydrophobic solids that produce a mixture with a reduced melting point. These include waxes (C26 and higher), paraffin waxes, cholesterol, fatty alcohols such as cetyl alcohol, mono-, di-, and / or triglycerides of animal and vegetable origin, such as hydrogenated beef tallow, hydrogenated fat, hydrogenated castor oil, fat derivatives such as fatty acids, soaps, esters, and hydrophobic starches such as ethylcellulose and lecithin. The waxes may be of natural origin, meaning they may be animal, vegetable, or mineral. Animal waxes include, but are not limited to, beeswax, lanolin, shellac, and Chinese insect wax. Vegetable waxes include, but are not limited to, carnauba, candelilla, berry tree, and sugarcane waxes.Mineral waxes include, but are not limited to, fossil or earth waxes, including ozokerite, ceresin, and montana waxes, or petroleum waxes, including paraffin and microcrystalline waxes. Alternatively, waxes may be synthetic or mixtures of natural and synthetic waxes. For example, synthetic waxes or mixtures of natural and synthetic waxes may include partially oxidized, low-molecular-weight polyethylene, which can be preferentially mistaken for paraffin. Fatty derivatives may be fatty acids, fatty acid amides, fatty alcohols, or fatty esters. C717ΠΠ / L7n7 / E / YIAI mixtures of these. The acid amide may be a esteramide. Sterols or long-chain sterol esters may also be such as cholesterol or ergosterol. A preferred hydrophobic coating material is palm oil or hydrogenated palm oil. Feed composition The granule of the present invention is suitable for use in animal feed compositions. The granule is mixed with feed substances. The characteristics of the granule allow its use as a component of a composition suitable for animal feed, which is steam-treated and then pelleted. The term "animal" includes all animals. Examples of animals are non-ruminants and ruminants, such as cows, sheep, and horses. In one particular sense, the animal is an animal that is not a ruminant. Non-ruminant animals include monogastric animals, e.g., pigs or swine (including, but not limited to, piglets, fattening pigs, and sows); poultry such as turkeys and chickens (including, but not limited to, broiler chickens and laying hens); young calves; and fish (including, but not limited to, salmon). The term feed or feed composition means any compound, preparation, mixture, or composition. The feed of the present invention may comprise vegetable proteins. The term "vegetable proteins," as used herein, refers to any compound, composition, preparation, or mixture that includes at least one protein derived from or originating from a vegetable, including modified proteins and protein derivatives. In particular embodiments, the protein content of the vegetable proteins is at least 10, 20, 30, 40, 50, or 60% (w / w). Plant proteins can be obtained from plant protein sources such as legumes and cereals, for example, materials from plants of the Fabaceae (Leguminosae), Cruciferaceae, Chenopodiaceae and Poaceae families, such as soybean meal, lupin meal and rapeseed meal. In one particular modality, the source of plant protein is material from one or more plants of the Fabaceae family, for example, soybeans, lupin, peas, or beans. In another particular modality, the source of plant protein is a material from one or more plants of the Chenopodiaceae family, for example, beetroot, sugar beetroot, spinach or quinoa. Other examples of plant-based protein sources are rapeseed and cabbage. Soybeans are a preferred source of plant-based protein. Other examples of plant protein sources are cereals such as barley, wheat, rye, oats, corn, rice, and sorghum. Suitable animal feed additives include enzyme inhibitors, fat-soluble vitamins, water-soluble vitamins, trace minerals, and macrominerals. In addition, feed additive ingredients are coloring agents, flavoring compounds, stabilizers, antimicrobial peptides and / or at least one other enzyme selected from phytases EC 3.1.3.8 or 3.1.3.26; xylanases EC 3.2.1.8; galactanases EC 3.2.1.89; and / or beta-glucanases EC 3.2.1.4. Examples of antimicrobial peptides (AMPs) are CAP18, Leukocin A, Trypticin, Protegrin-1, Thanatin, Defensin, Ovispirin such as Novispirin (Robert Lehrer, 2000), and variants or fragments thereof that retain antimicrobial activity. Examples of antifungal polypeptides (AFPs) include the peptides of Aspergillus giganteus and Aspergillus niger, as well as variants and fragments of these that retain antifungal activity, as described in documents WO 94 / 01459 and PCT / DK02 / 00289. Normally, fat-soluble and water-soluble vitamins, as well as trace minerals, are part of the so-called premix intended to be added to the feed, while macrominerals are usually added separately to the feed. The following are non-exclusive lists of examples of cz / znn / Lznz / E / γΐΛΐ these components: Some examples of fat-soluble vitamins are vitamin A, vitamin D3, vitamin E, and vitamin K, e.g., vitamin K3. Some examples of water-soluble vitamins are vitamin B12, biotin and choline, vitamin B1, vitamin B2, vitamin B6, niacin, folic acid and pantothenate, e.g., CaD-pantothenate. Examples of trace minerals include manganese, zinc, iron, copper, iodine, selenium, and cobalt. Examples of macrominerals include calcium, phosphorus, and sodium. In other additional particular forms, the animal feed composition contains 0-80% maize; and / or 0-80% sorghum; and / or 0-70% wheat; and / or 0-70% barley; and / or 0-30% oats; and / or 0-40% soybean meal; and / or 0-10% fishmeal; and / or 0-20% whey. Preparation Preparation of the granule core The core of the granule of the invention may comprise muramidase in the form of a concentrated dry matter. In one embodiment, the concentrated dry matter is prepared by spray drying. Methods for preparing the core can be found in the Handbook of Powder Technology; Particle size enlargement of cz i znn / Lznz / E / YiAi CE Capes; Volume 1; 1980; Elsevier. Preparation methods include known feed and pellet formulation technologies, namely: a) Spray-dried products, where a liquid solution containing muramidase is atomized in a spray-drying tower to form microdroplets that, during their downward path through the drying tower, dry to form a particulate material containing muramidase. Very small particles can be produced in this way (Michael S. Showell (editor); Powdered detergent; Surfactant Science Series; 1998; vol. 71; pp. 140-142; Marcel Dekker). (b) Layered products, wherein the muramidase is in the form of a layer coating a preformed inert nuclear particle, wherein a solution containing muramidase is atomized, typically in a fluidized bed apparatus where the preformed nuclear particles are fluidized, and the solution containing the enzyme adheres to the nuclear particles and dries to leave a layer of dried muramidase on the surface of the nuclear particle. Particles of a desired size can be obtained in this way if a useful nuclear particle of the desired size can be found. This type of product is described in, e.g., WO 97 / 23606. c) Absorbed nuclear particles, where instead of coating the muramidase as a layer around the nucleus, the cz j znn / Lznz / E / YiAi muramidase is absorbed onto and / or within the surface of the nucleus. Such a process is described in WO 97 / 39116. d) Extruded or pelleted products, in which a paste containing muramidase is pressed into pellets or extruded under pressure through a small opening and cut into particles that are subsequently dried. Such particles are usually of considerable size because the material in which the extrusion opening is made (usually a plate with perforated holes) limits the pressure drop that can be allowed across the opening. In addition, very high extrusion pressures when using a small opening increase heat generation in the muramidase paste, which is harmful to the muramidase. (Michael S. Showell (editor); Powdered detergents; Surfactant Science Series; 1998; vol. 71; pages 140-142; Marcel Dekker). (e) Agglomerated products, in which an active powder is suspended in molten wax and the suspension is sprayed, e.g., through a rotating disc atomizer, into a cooling chamber where the microdroplets solidify rapidly (Michael S. Showell (editor); Powdered detergents; Surfactant Science Series; 1998; vol. 71; pages 140-142; Marcel Dekker). The resulting product is one in which the muramidase is uniformly distributed throughout the inert material rather than concentrated on its surface. Furthermore, US patents 4,016,040 and 4,713,245 are documents related to this technique. f) Mixer granulation products, in which a liquid containing active ingredients is added to a composition of conventional granulation components. The liquid and powder are mixed in a suitable ratio, and as moisture from the liquid is absorbed into the dry powder, the components of the dry powder begin to adhere and agglomerate, and particles accumulate, forming granules comprising muramidase. Such a method is described in US patent 4,106,991 (NOVO NORDISK) and related documents EP 170360 B1 (NOVO NORDISK), EP 304332 B1 (NOVO NORDISK), EP 304331 (NOVO NORDISK), WO 90 / 09440 (NOVO NORDISK), and WO 90 / 09428 (NOVO NORDISK). In a particular product of this process, in which various high-shear mixers can be used as granulators, granules consisting of enzyme-like materials, fillers, binders, etc., are mixed with cellulose fibers to reinforce the particles to obtain the so-called T-shaped granule.The reinforced particles, which are more robust, release less enzymatic dust. g) Size reduction, in which the cores are produced by grinding or crushing larger particles, pellets, tablets, briquettes, etc., containing the C717ΠΠ / ί7Π7 / E / YILI active material. The desired nuclear particle fraction is obtained by sieving the ground or crushed product. Oversized and undersized particles can be recycled. Size reduction is described in (Martin Rhodes (editor); Principles of Powder Technology; 1990; Chapter 10; John Wiley & Sons). h) Fluidized bed granulation. Fluidized bed granulation involves suspending particles in an air stream and spraying a liquid onto the fluidized particles through nozzles. The particles struck by the spray microdroplets become moistened and sticky. The sticky particles collide with other particles, adhere to them, and form a granule. (i) The cores may be subjected to drying, such as in a fluidized bed dryer. Those skilled in the art may use other methods known for drying granules in the feed or enzyme industries. Drying is preferably carried out at a product temperature of 25 to 90 °C. For some muramidases, it is important that the cores comprising the muramidase contain a low amount of water before coating with salt. If water-sensitive muramidases are coated with salt before removing excess water, the water will be trapped within the core and may adversely affect the muramidase activity. After drying, the cores preferably contain 0.1–10% water (w / w). Preparation of the inner salt layer The internal salt layer can be applied to the core of the granule comprising the muramidase by atomization onto the core granules in a fluidized bed. The internal salt layer can also be applied in vacuum mixers, dragee-type coaters (drum-type coaters), seed coating equipment, equipment comprising rotary bottoms (e.g., Roto Glatt, CF granulators (Freund), torbed processors (Gauda) or in rotary fluidized bed processors such as Omnitex (Nara)). After applying the salt coating, the granule can optionally be dried. Drying of the salt-coated granule can be carried out using any drying method available to the skilled worker, such as spray drying, freeze-drying, vacuum drying, fluidized bed drying, drum coating, and microwave drying. Drying of the salt-coated granule can also be combined with granulation methods that include, for example, the use of a fluidized bed, a fluidized bed spray dryer (FSD), or a multi-stage dryer (MSD). Preparation of the outer hydrophobic layer Coatings and conventional methods as known in the art can be used appropriately, such as C717ΠΠ / ί7Π7 / E / YΙΛΙ as the coatings described in Danish document PA 2002 00473, document WO 89 / 08694, document WO 89 / 08695, document 270 608 B1 and / or document WO 00 / 01793. Other examples of conventional coating materials can be found in documents US 4,106,991, EP 170360, EP 304332, EP 304331, EP 458849, EP 458845, WO 97 / 39116, WO 92 / 12645A, WO 89 / 08695, WO 89 / 08694, WO 87 / 07292, WO 91 / 06638, WO 92 / 13030, WO 93 / 07260, WO 93 / 07263, WO 96 / 38527, WO 96 / 16151, WO 97 / 23606, WO 01 / 25412, WO 02 / 20746, WO 02 / 28369, US 5879920, US 5,324,649, US 4,689,297, US 6,348,442, EP 206417, EP 193829, DE 4344215, DE 4322229 A, DE 263790, JP 61162185 A and / or JP 58179492. The coating can be prepared using the same methods mentioned above in the Core Preparation and Salt Coating Preparation sections. The resulting granules can be subjected to rounding (e.g., spheronization), such as in a Marumeriser™, or compaction. The granules can be dried, such as in a fluidized bed dryer. Those skilled in the art may use other methods known for drying granules in the feed or enzyme industries. Drying is preferably carried out at a product temperature of 25 to 90 °C. Manufacturing of feed pellets In the manufacture of feed pellets, it is preferred to involve steam treatment before pelleting, a process called conditioning. In the subsequent pelleting stage, the feed is passed through a trogel and the resulting strips are cut into suitable pellets of varying lengths. During this conditioning stage, the temperature of the method can be raised to 60-100 °C. The feed mixture is prepared by mixing the granules comprising muramidase with the desired feed components. The mixture is conveyed to a conditioner, e.g., a steam-injected cascade mixer. The feed is heated in the conditioner to a specified temperature, 60–100 °C, for example, 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, by steam injection, measured at the conditioner outlet. The residence time can vary from seconds to minutes and even hours, such as 5 seconds, 10 seconds, 15 seconds, 30 seconds, 1 minute, 2 minutes, 5 minutes, 10 minutes, 15 minutes, 30 minutes, and 1 hour. In a particular embodiment of the present invention, the temperature is 100 °C and the residence time is 60 seconds. In one particular embodiment of the present invention, the temperature of the method during steam treatment is at least 60 °C. In a more particular embodiment of the present invention, the temperature of the method during steam treatment is at least 70 °C. In a still more particular embodiment of the present invention, the temperature of the method during steam treatment is at least 80 °C. In a most particular embodiment, the temperature of the method during steam treatment is at least 90 °C. From the conditioner, the feed is directed to a press, for example, a Simon Heesen press, and is pressed into pellets with a variable length of approximately 15 mm. After pressing, the pellets are placed in an air cooler and cooled for a specific time, for example, 15 minutes. A particular embodiment of the present invention is a method for manufacturing a feed composition comprising the steps of: i. mixing feed components with granules comprising a core, an inner salt layer and an outer hydrophobic layer where the core comprises a muramidase, ii. steam treating the composition (i), and iii. pelletizing the composition (ii). In one embodiment, the muramidase present in the pellet core retained at least 75% of its activity after steam pelleting of the feed at 85 degrees Celsius compared to its activity before steam pelleting. In a further embodiment, the muramidase present in the pellet core retained at least 75% of its activity after steam pelleting of the feed at 85 degrees Celsius. C717PΠ / ί7P7 / E / YILI Muramidase activity in the granule core after steam pelleting at 90 degrees Celsius compared to the activity before steam pelleting. In a further embodiment, the muramidase present in the granule core retained at least 75% of the muramidase activity in the granule core after steam pelleting at 95 degrees Celsius compared to the activity before steam pelleting. In a further embodiment, the muramidase present in the granule core retained at least 80% of the muramidase activity in the granule core after steam pelleting at 85 degrees Celsius compared to the activity before steam pelleting.In an additional embodiment, the muramidase present in the granule core retained at least 80% of its activity after steam pelleting at 90 degrees Celsius compared to its activity before steam pelleting. In another embodiment, the muramidase present in the granule core retained at least 80% of its activity after steam pelleting at 95 degrees Celsius compared to its activity before steam pelleting. In yet another embodiment, the muramidase present in the granule core retained at least 85% of its activity after steam pelleting at 85 degrees Celsius compared to its activity before steam pelleting.In an additional embodiment, the muramidase present in the granule core retained at least 85% of its activity after steam pelleting at 90 degrees Celsius compared to its activity before steam pelleting. In another embodiment, the muramidase present in the granule core retained at least 85% of its activity after steam pelleting at 95 degrees Celsius compared to its activity before steam pelleting. PREFERRED ASPECTS The present invention is further described by the following examples, which should not be considered as limiting the scope of the invention. 1. A pelleted feed composition comprising a granule comprising a core and a coating, wherein the core comprises a muramidase and the coating comprises an internal salt layer and an external hydrophobic layer. 2. The composition of feed according to aspect 1 that has been exposed to steam treatment. 3. The feed composition according to aspect 1 or 2, in which the internal salt layer contributes between 20-70% w / w of the C717ΠΠ / L7n7 / E / YIAI granule. 4. The feed composition according to aspect 3, wherein the internal salt layer contributes between 30-60% w / w of the granule, such as 40-60% w / w. 5. The feed composition according to aspect 4, in which the internal salt layer contributes between 50-60% w / w of the granule. 6. The feed composition according to aspect 1 or 2, in which the internal salt layer contributes between 40% w / w of the granule. 7. The feed composition according to aspect 1 or 2, in which the internal salt layer contributes between 50% w / w of the granule. 8. The feed composition according to aspect 1 or 2, in which the internal salt layer contributes between 60% w / w of the granule. 9. The feed composition according to any one of aspects 1 to 8, wherein the thickness of the internal salt layer is at least 15 pm. 10. The feed composition according to any one of aspects 1 to 8, wherein the thickness of the internal salt layer is at least 22 pm. 11. The feed composition according to any one of aspects 1 to 8, wherein the thickness of the internal salt layer is at least 30 pm. cz i znn / Lznz / E / YiAi 12. The feed composition according to any one of aspects 1 to 8, wherein the thickness of the internal salt layer is at least 37 pm. 13. The feed composition according to any one of aspects 1 to 8, wherein the thickness of the internal salt layer is at least 45 pm. 14. The feed composition according to any one of aspects 1 to 8, wherein the thickness of the internal salt layer is at least 52 pm. 15. The feed composition according to any one of aspects 1 to 14, wherein the inner salt layer comprises one or more salts selected from the group consisting of: NaCl, Na2CO3, NaNO3, Na2HPO4, Na3PO4, NH4C1, (NH4)2HPO4, NH4H2PO4, (NH4)2SO4, KC1, K2HPO4, KH2PO4, KNO3, Na2SO4, K2SO4, KHSO4, MgSO4, ZnSO4, CuSO4, sodium citrate and mixtures thereof. 16. The feed composition according to any one of aspects 1 to 15, wherein the inner salt layer comprises Na2SO4, K2SO4, MgSO4 or a mixture of these. 17. The feed composition according to any one of aspects 1 to 16, wherein the inner salt layer comprises Na2SO4. 18. The composition of feed according to any one of aspects 1 to 17, wherein the outer hydrophobic layer contributes between 1-10% w / w of the granule. 19. The composition of feed according to any one of cz i znn / Lznz / E / YiAi aspects 1 to 18, wherein the outer hydrophobic layer contributes between 1-5% w / w of the granule. 20. The composition of feed according to aspect 19, in which the outer hydrophobic layer contributes between 2-3% w / w of the granule. 21. The composition of feed according to aspect 20, in which the outer hydrophobic layer contributes about 2% w / w of the granule. 22. The feed composition according to aspect 20, in which the outer hydrophobic layer contributes about 3% w / w of the granule. 23. The feed composition according to any one of aspects 1 to 22, wherein the thickness of the outer hydrophobic layer is at least 1 pm. 24. The feed composition according to any one of aspects 1 to 22, wherein the thickness of the outer hydrophobic layer is at least 1.5 pm. 25. The feed composition according to any one of aspects 1 to 22, wherein the thickness of the outer hydrophobic layer is at least 2 pm. 26. The feed composition according to any one of aspects 1 to 22, wherein the thickness of the outer hydrophobic layer is at least 4 pm. 27. The feed composition according to any one of aspects 1 to 22, wherein the thickness of the external hydrophobic layer cz i znn / Lznz / E / γΐΛΐ is at least 7 pm. 28. The feed composition according to any one of aspects 1 to 27, wherein the outer hydrophobic layer comprises one or more hydrophobic coating materials selected from the group consisting of: hydrogenated castor oil, hydrogenated palm kernel oil, hydrogenated palm oil, hydrogenated cottonseed oil, hydrogenated soybean seed oil, hydrogenated rapeseed oil, a mixture of hydrogenated and non-hydrogenated vegetable oil, 12-hydroxystearic acid, microcrystalline wax, high melting point paraffin waxes and mixtures thereof. 29. The feed composition according to any one of aspects 1 to 28, wherein the outer hydrophobic layer comprises hydrogenated palm oil. 30. The feed composition according to any one of aspects 1 to 29, wherein the pellet further comprises a processing aid. 31. The feed composition according to any one of aspects 1 to 30, wherein the processing aid is provided as a spray. 32. The feed composition according to aspect 30 or 31, in which the processing aid is CaCO3, talc and / or kaolin. 33. The feed composition according to any one of aspects 1 to 32, wherein the granules have a particle size of between 50 pm - 2000 pm. 34. The composition of feed according to any one of aspects 1 to 33, wherein the granules have a particle size of between 100 pm - 1500 pm. 35. Feed composition according to any one of aspects 1 to 34, wherein the granules have a particle size less than 1200 pm. 36. The composition of feed according to any one of aspects 1 to 35, wherein the granules have a particle size greater than 250 pm. 37. The composition of feed according to any one of aspects 1 to 36, wherein the granules have a particle size of between 250 pm - 1200 pm. 38. The composition of feed according to any one of aspects 1 to 37, wherein the granules have a particle size of between 250 pm - 900 pm. 39. The composition of feed according to any one of aspects 1 to 37, wherein the granules have a particle size of between 600 pm - 1200 pm. 40. The composition of feed according to any one of aspects 1 to 37, wherein the granules have a particle size of between 600 pm - 900 pm. 41. The feed composition according to any one of aspects 1 to 37, wherein the granules have a medium particle size of between 500 pm - 700 pm. 42. The composition of feed according to any one of aspects 1 to 41, wherein muramidase is muramidase GH2 5. 43. The composition of feed according to any one of aspects 1 to 42, wherein muramidase has the ability to lyse bacterial cell walls. 44. The feed composition according to any one of aspects 1 to 43, wherein muramidase has lysozyme activity against peptidoglycans found in the cell walls of Micrococcus lysodeikticus. 45. The feed composition according to any one of aspects 1 to 44, wherein muramidase has lysozyme activity against Lactobacillus johnsonii. 46. ​​The feed composition according to any one of aspects 1 to 45, wherein muramidase is an isolated polypeptide selected from the group consisting of: (a) a polypeptide having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity with the mature polypeptide of SEC. ID NO.: 2 or the mature polypeptide of SEC. ID NO.: 4; (b) a polypeptide encoded by a polynucleotide having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity with the mature polypeptide coding sequence of SEC. ID NO.: 1 or with the mature polypeptide coding sequence of SEC. ID NO.: 3; (c) a polypeptide encoded by a polynucleotide that hybridizes under medium-high astringency conditions with the coding sequence of the mature polypeptide of SEC. ID. NO.: 1 or SEC. ID. NO.: 3 or the full length complement thereof; (d) a variant of the mature polypeptide of SEC. ID NO.: 2 or SEC. ID NO.: 4 comprising a substitution, deletion and / or insertion at one or more positions (e.g., several); and (e) a polypeptide fragment of (a), (b), (c) or (d) having lysozyme activity. 47. The composition of feed according to any one of aspects 1 to 46, wherein muramidase is thermolabile. 48. The feed composition according to any one of aspects 1 to 47, wherein the muramidase is selected from the polypeptides comprising or consisting of a mature polypeptide of SEC. ID NO.: 2 or SEC. ID NO.: 4. 49. The feed composition according to any one of aspects 1 to 48, wherein the moisture content of the crushed composition is at least 11% before pelleting and conditioning. 50. The feed composition according to any one of aspects 1 to 49, wherein the moisture content of the crushed composition is between 11 and 15% before pelleting and conditioning. 51. The feed composition according to any one of aspects 1 to 50, wherein the moisture content of the crushed composition is between 12 and 14% before pelleting and conditioning. 52. The feed composition according to any one of aspects 1 to 50, wherein the moisture content of the crushed composition is about 11% before pelleting and conditioning. 53. The feed composition according to any one of aspects 1 to 50, wherein the moisture content of the crushed composition is about 12% before pelleting and conditioning. 54. The feed composition according to any one of aspects 1 to 50, wherein the moisture content of the crushed composition is about 13% before pelleting and conditioning. 55. The feed composition according to any one of aspects 1 to 50, wherein the moisture content of the crushed composition is about 14% before pelleting and conditioning. 56. The feed composition according to any one of aspects 1 to 50, wherein the moisture content of the crushed composition is about 15% before pelleting and conditioning. 57. The composition of feed according to any one of aspects 1 to 56, wherein the core further comprises a salt. 58. The composition of feed according to aspect 57, in which salt is a stabilizer. 59. The feed composition according to aspect 57 or 58, wherein the salt is selected from the group consisting of: Na2SO4, MgSO4 and ZnSO4. 60. The composition of feed according to aspect 57 or 58, in which the salt is Na2SO4. 61. The feed composition according to any one of aspects 1 to 60, wherein the retained muramidase activity present in the pellet core after pelleting at 85 degrees Celsius is at least 75% of the muramidase activity in the pellet core before steam pelleting. 62. The feed composition according to any one of aspects 1 to 60, wherein the retained activity of muramidase present in the pellet core after pelleting at 90 degrees Celsius is at least 75% of the C717ΠΠ / ί7Π7 / E / YΙΛΙ muramidase activity in the granule core before steam pelleting. 63. Feed composition according to any one of aspects 1 to 60, wherein the retained muramidase activity present in the pellet core after pelleting at 95 degrees Celsius is at least 75% of the muramidase activity in the pellet core before steam pelleting. 64. Feed composition according to any one of aspects 1 to 60, wherein the retained muramidase activity present in the pellet core after pelleting at 85 degrees Celsius is at least 80% of the muramidase activity in the pellet core before steam pelleting. 65. The feed composition according to any one of aspects 1 to 60, wherein the retained muramidase activity present in the pellet core after steam pelleting at 90 degrees Celsius is at least 80% of the muramidase activity in the pellet core before steam pelleting. 66. The feed composition according to any one of aspects 1 to 60, wherein the retained muramidase activity present in the core of the pellets after steam pelleting at 95 degrees Celsius is at least 80% of the muramidase activity in the core of the pellets cz i znn / Lznz / E / γΐΛΐ before steam pelleting. 67. The feed composition according to any one of aspects 1 to 60, wherein the retained muramidase activity present in the pellet core after steam pelleting at 85 degrees Celsius is at least 85% of the muramidase activity in the pellet core before steam pelleting. 68. Feed composition according to any one of aspects 1 to 60, wherein the retained muramidase activity present in the pellet core after steam pelleting at 90 degrees Celsius is at least 85% of the muramidase activity in the pellet core before steam pelleting. 69. The feed composition according to any one of aspects 1 to 60, wherein the retained muramidase activity present in the pellet core after steam pelleting at 95 degrees Celsius is at least 85% of the muramidase activity in the pellet core before steam pelleting. 70. The feed composition according to any one of aspects 1 to 69, wherein the core is a homogeneous enzyme mixture including one or more muramidases, an inert particle with muramidase and optionally additional enzymes applied thereto, or a homogeneous enzyme mixture including one or more muramidases and materials that act as binders that are coated with one or more muramidases. 71. The composition of feed according to any one of aspects 1 to 70, in which the pellets release only a low amount of dust. 72. Feed composition according to any one of aspects 1 to 71, wherein the pellets produce little or no dust when measured by the Type 1 Heubach test or the settling test as described in the definition of dust. 73. The feed composition according to any one of aspects 1 to 72, wherein the dust is below 1000 pg / g in the Type 1 Heubach test and / or below 1000 pg / g in the settling test. In an additional aspect, the dust is below 500 pg / g in the Heubach Type 1 test, below 250 pg / g in the Heubach Type 1 test, below 100 pg / g in the Heubach Type 1 test, or below 50 pg / g in the Heubach Type 1 test. In yet another aspect, the dust is below 500 pg / g in the decantation test, below 250 pg / g in the decantation test, below 100 pg / g in the decantation test, or below 50 pg / g in the decantation test. 74. The feed composition according to any one of aspects 1 to 73, in which the useful life of the cz i znn / Lznz / E / YiAi granules is retained. 75. A granule comprising a core and a coating, wherein the core comprises a muramidase and the coating comprises an inner salt layer and an outer hydrophobic layer. 76. A granule comprising a core and a coating, wherein the core comprises a muramidase and the coating comprises an inner salt layer and an outer hydrophobic layer, wherein the granule comprises at least 75% muramidase with retained activity after steam pelleting compared to the activity before steam pelleting, and wherein the granule further comprises one or more of the following: v. the particle size of the granule is below 1200 pm, vi. the thickness of the internal salt layer is at least 15 pm, vii. the thickness of the external hydrophobic coating is at least 1 pm, and viii. muramidase is thermolabile 77. The granule according to aspect 75 or 76 that has been exposed to steam treatment. 78. The granule according to any one of aspects 75 to 77, wherein the internal salt layer contributes between 20-70% w / w of the granule. cz i znn / Lznz / E / YiAi 79. The granule according to aspect 78, wherein the internal salt layer contributes between 30-60% w / w of the granule, such as 40-60% w / w. 80. The granule according to any one of aspects 75 to 78, wherein the internal salt layer contributes between 50-60% w / w of the granule. 81. The granule according to any one of aspects 75 to 78, wherein the internal salt layer contributes about 40% w / w of the granule. 82. The granule according to any one of aspects 75 to 78, wherein the internal salt layer contributes about 50% w / w of the granule. 83. The granule according to any one of aspects 75 to 78, wherein the internal salt layer contributes about 60% w / w of the granule. 84. The granule according to any one of aspects 75 to 83, wherein the thickness of the internal salt layer is at least 15 pm. 85. The granule according to any one of aspects 75 to 83, wherein the thickness of the internal salt layer is at least 22 pm. 86. The granule according to any one of aspects 75 to 83, wherein the thickness of the internal salt layer is at least 30 pm. 87. The granule according to any one of the aspects 75 C717ΠΠ / ί7Π7 / E / YΙΛΙ to 83, in which the thickness of the internal salt layer is at least 37 pm. 88. The granule according to any one of aspects 75 to 83, wherein the thickness of the internal salt layer is at least 45 pm. 89. The granule according to any one of aspects 75 to 83, wherein the thickness of the internal salt layer is at least 52 pm. 90. The granule according to any one of aspects 75 to 89, wherein the inner salt layer comprises one or more salts selected from the group consisting of: NaCl, Na2CO3, NaNO3, Na2HPO4, Na3PO4, NH4C1, (NH4)2HPO4, NH4H2PO4, (NH4)2SO4, KC1, K2HPO4, KH2PO4, KNO3, Na2SO4, K2SO4, KHSO4, MgSO4, ZnSO4, CuSO4, sodium citrate and mixtures thereof. 91. The granule according to any one of aspects 75 to 90, wherein the internal salt layer comprises Na2SO4, K2SO4, MgSO4 or a mixture of these. 92. The granule according to any one of aspects 75 to 91, wherein the internal salt layer comprises Na2SO4. 93. The granule according to any one of aspects 75 to 92, wherein the outer hydrophobic layer contributes between 100% w / w of the granule. 94. The granule according to any one of aspects 75 to 93, wherein the outer hydrophobic layer contributes between 10% w / w of the granule. cz i znn / Lznz / E / YiAi 95. The granule according to any one of aspects 75 to 94, wherein the outer hydrophobic layer contributes between 23% w / w of the granule. 96. The granule according to aspect 95, wherein the outer hydrophobic layer contributes about 2% w / w of the granule. 97. The granule according to aspect 95, wherein the outer hydrophobic layer contributes about 3% w / w of the granule. 98. The granule according to any one of aspects 75 to 97, wherein the thickness of the outer hydrophobic layer is at least 1 pm. 99. The granule according to any one of aspects 75 to 97, wherein the thickness of the outer hydrophobic layer is at least 1.5 pm. 100. The granule according to any one of aspects 75 to 97, wherein the thickness of the outer hydrophobic layer is at least 2 pm. 101. The granule according to any one of aspects 75 to 97, wherein the thickness of the outer hydrophobic layer is at least 4 pm. 102. The granule according to any one of aspects 75 to 97, wherein the thickness of the outer hydrophobic layer is at least 7 pm. 103. The feed composition according to any one of aspects 75 to 102, wherein the outer hydrophobic layer comprises one or more hydrophobic coating materials selected from the group consisting of: hydrogenated castor oil, hydrogenated palm kernel oil, hydrogenated palm oil, hydrogenated cottonseed oil, hydrogenated soybean seed oil, hydrogenated rapeseed oil, a mixture of hydrogenated and non-hydrogenated vegetable oil, 12-hydroxystearic acid, microcrystalline wax, high melting point paraffin waxes and mixtures thereof. 104. The granule according to any one of aspects 75 to 103, wherein the outer hydrophobic layer comprises hydrogenated palm oil. 105. The granule according to any one of aspects 75 to 104, wherein the granule further comprises a processing aid. 106. The granule according to aspect 105, wherein the processing aid is provided as a spray. 107. The granule according to aspect 105 or 106, in which the processing aid is CaCO3, talc and / or kaolin. 108. The granule according to any one of aspects 75 to 107, wherein the granules have a particle size of between 50 pm - 2000 pm. 109. The granule according to any one of aspects 75 to 108, wherein the granules have a particle size of between 100 pm - 1500 pm. 110. The granule according to any one of the aspects 75 to 109, wherein the granules have a particle size C717ΠΠ / L7n7 / E / YIAI less than 1200 pm. 111. The granule according to any one of aspects 75 to 110, wherein the granules have a particle size greater than 250 pm. 112. The granule according to any one of aspects 75 to 111, wherein the granules have a particle size of between 250 pm - 1200 pm. 113. The granule according to any one of aspects 75 to 111, wherein the granules have a particle size of between 250 pm - 900 pm. 114. The granule according to any one of aspects 75 to 111, wherein the granules have a particle size of between 600 pm - 1200 pm. 115. The granule according to any one of aspects 75 to 111, wherein the granules have a particle size of between 600 pm - 900 pm. 116. The granule according to any one of aspects 75 to 111, wherein the granules have an average particle size of between 500 pm - 700 pm. 117. The granule according to any one of aspects 75 to 116, wherein the muramidase is muramidase GH25. 118. The granule according to any one of the aspects 75 to 117, in which muramidase has the ability to lyse bacterial cell walls. 119. The granule according to any one of the aspects 75 cz i znn / Lznz / E / γΐΛΐ a 118, wherein muramidase has lysozyme activity against peptidoglycans found in the cell walls of Micrococcus lysodeikticus. 120. The granule according to any one of aspects 75 to 119, wherein muramidase has lysozyme activity against Lactobacillus johnsonii. 121. The granule according to any one of aspects 75 to 120, wherein the muramidase is an isolated polypeptide selected from the group consisting of: (a) a polypeptide having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity with the mature polypeptide of SEC. ID NO.: 2 or the mature polypeptide of SEC. ID NO.: 4; (b) a polypeptide encoded by a polynucleotide having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% sequence identity with the mature polypeptide coding sequence of SEC. ID NO.: 1 or with the mature polypeptide coding sequence of SEC. ID NO.: 3; (c) a polypeptide encoded by a polynucleotide that hybridizes under medium-high astringency conditions with the coding sequence of the mature polypeptide of SEO. ID. NO.: 1 or the SEC. ID NO.: 3 or the full length complement thereof; (d) a variant of the mature polypeptide of SEC. ID NO.: 2 or SEC. ID NO.: 4 comprising a substitution, deletion and / or insertion at one or more positions (e.g., several); and (e) a polypeptide fragment of (a), (b), (c) or (d) having lysozyme activity. 122. The granule according to any one of the aspects 75 to 121, wherein the muramidase is thermolabile. 123. The granule according to any one of aspects 75 to 122, wherein the muramidase is selected from the polypeptides comprising or consisting of a mature polypeptide of SEC. ID NO.: 2 or SEC. ID NO.: 4. 124. The granule according to any one of aspects 75 to 123, wherein the moisture content of the crushed composition is at least 11% before pelletizing and conditioning. 125. The granule according to any one of aspects 75 to 123, wherein the moisture content of the crushed composition is between 11 and 15% before pelletizing and conditioning. 126. The granule according to any one of aspects 75 to 123, wherein the moisture content of the crushed composition is between 12 and 14% before pelletizing and conditioning. 127. The granule according to any one of aspects 75 to 123, wherein the moisture content of the crushed composition is about 11% before pelletizing and conditioning. 128. The granule according to any one of aspects 75 to 123, wherein the moisture content of the crushed composition is about 12% before pelletizing and conditioning. 129. The granule according to any one of aspects 75 to 123, wherein the moisture content of the crushed composition is about 13% before pelletizing and conditioning. 130. The granule according to any one of aspects 75 to 123, wherein the moisture content of the crushed composition is about 14% before pelletizing and conditioning. 131. The granule according to any one of aspects 75 to 123, wherein the moisture content of the crushed composition is about 15% before pelletizing and conditioning. 132. The granule according to any one of the aspects 75 to 131, wherein the core further comprises a salt. 133. The granule according to aspect 132, wherein the salt cz i znn / Lznz / E / γΐΛΐ is a stabilizer. 134. The granule according to aspect 132 or 133, wherein the salt is selected from the group consisting of: Na2SO4, MgSO4 and ZnSO4. 135. The granule according to aspect 132 or 133, in which the salt is Na2SO4. 136. The pellet according to any one of aspects 75 to 135, wherein the retained muramidase activity present in the pellet core after pelleting at 85 degrees Celsius is at least 75% of the muramidase activity in the pellet core before steam pelleting. 137. The pellet according to any one of aspects 75 to 135, wherein the retained muramidase activity present in the pellet core after pelleting at 90 degrees Celsius is at least 75% of the muramidase activity in the pellet core before steam pelleting. 138. The pellet according to any one of aspects 75 to 135, wherein the retained muramidase activity present in the pellet core after pelleting at 95 degrees Celsius is at least 75% of the muramidase activity in the pellet core before steam pelleting. 139. The granule according to any one of the aspects 75 cz i znn / Lznz / E / γΐΛΐ to 135, wherein the retained muramidase activity present in the core of the granules after pelleting at 85 degrees Celsius is at least 80% of the muramidase activity in the core of the granules before steam pelleting. 140. The pellet according to any one of aspects 75 to 135, wherein the retained muramidase activity present in the pellet core after pelleting at 90 degrees Celsius is at least 80% of the muramidase activity in the pellet core before steam pelleting. 141. The pellet according to any one of aspects 75 to 135, wherein the retained muramidase activity present in the pellet core after pelleting at 95 degrees Celsius is at least 80% of the muramidase activity in the pellet core before steam pelleting. 142. The pellet according to any one of aspects 75 to 135, wherein the retained muramidase activity present in the pellet core after pelleting at 85 degrees Celsius is at least 85% of the muramidase activity in the pellet core before steam pelleting. 143. The pellet according to any one of aspects 75 to 135, wherein the retained muramidase activity present in the pellet core after pelleting at 90 degrees Celsius is at least 85% of the muramidase activity in the pellet core before steam pelleting. 144. The pellet according to any one of aspects 75 to 135, wherein the retained muramidase activity present in the pellet core after pelleting at 95 degrees Celsius is at least 85% of the muramidase activity in the pellet core before steam pelleting. 145. The granule according to any one of aspects 75 to 144, wherein the core is a homogeneous enzyme mixture including one or more muramidases, an inert particle with muramidase and optionally additional enzymes applied thereto, or a homogeneous enzyme mixture including one or more muramidases and binder-acting materials coated with one or more muramidases. 146. The granule according to any one of aspects 75 to 145, wherein the granules release only a low amount of dust. 147. The granule according to any one of aspects 75 to 146, wherein the granules produce little or no dust when measured by the Type 1 Heubach test or the settling test as described in the definition of dust. 148. The granule according to any one of the aspects 75 cz i znn / Lznz / E / γΐΛΐ to 147, wherein the dust is below 1000 pg / g in the Type 1 Heubach test and / or below 1000 pg / g in the decantation test. In an additional aspect, the dust is below 500 pg / g in the Heubach Type 1 test, below 250 pg / g in the Heubach Type 1 test, below 100 pg / g in the Heubach Type 1 test, or below 50 pg / g in the Heubach Type 1 test. In yet another aspect, the dust is below 500 pg / g in the decantation test, below 250 pg / g in the decantation test, below 100 pg / g in the decantation test, or below 50 pg / g in the decantation test. 149. The granule according to any one of the aspects 75 to 148, in which the useful life of the granules is retained. 150. A method for feeding animals comprising administering the feed composition of any one of aspects 1 to 74 to an animal. 151. A method for manufacturing a feed composition comprising the following steps: (i) mixing feed components with granules comprising a core, an inner coating and an outer coating wherein the core comprises a muramidase, the inner coating comprises a salt and the outer coating comprises a hydrophobic coating material, (ii) steam treating composition (i), and C717ΠΠ / ί7Π7 / Ε / ΥΙΛΙ (iii) pelletize the composition. 152. A method for improving the stability of muramidase comprising incorporating muramidase into a feed composition according to any one of aspects 1 to 74 or a pellet according to any one of aspects 75 to 149. 153. A method for improving the stability of muramidase in a crushed composition having a moisture content above 12% comprising incorporating the muramidase into a feed composition according to any one of aspects 1 to 74 or a pellet according to any one of aspects 75 to 149. 154. The use of a granule comprising a muramidase, an inner salt layer and an outer hydrophobic layer according to any one of aspects 75 to 149 for preparing steam-treated pelleted feed compositions. EXAMPLES Example 1 Granule 1, granule comprising a core comprising a muramidase, and a salt layer in the core: A powder mixture with the following composition 960 g of cellulose, Arbocel BC200 600 g of dextrin, kaolin 2534 g of spray-dried GH25 muramidase powder 7552 g of ground Na2SO4 was granulated in a Lódige FM 50 mixer with a granulation liquid consisting of 480 g of sucrose 2220 g of water The granulation process was described in US patent 4,106,991, example 1. The resulting granules were dried in a fluid bed dryer to a water content of less than 1% and were sieved to obtain a product with a particle size between 250 and 1200 micrometers. 4.0 kg of the granule cores described above were placed in a fluidized bed MP1. The following mixture was prepared to apply a layer of salt to the cores: 1600 g of Na2SO4 4000 g of water The following bed placement was used during coating: Airflow: 215 m3 / hour Inlet temperature 90 °C Product temperature: 44 °C Bobbin size: 1.2 mm Nozzle pressure: 3.0 bar After coating, the granules were dried for 10 min. to reach a temperature of 75 °C and finally cooled. Granule 2, granule comprising a core comprising muramidase, an internal salt layer in the core and an external hydrophobic layer in the internal salt layer. 2.0 kg of granule 1 were placed in a Lódige L 5 mixer. The following mixture was prepared to apply a hydrophobic layer to the salt layer: g melted hydrogenated palm oil 120 g of kaolin After coating, the final product was cooled in an MP 2 fluid bed. Pelletizing stability measurements: Granules 1 and 2 were pelleted using different pelleting conditions and different moisture content in the feed formulation. Experimental setup: Approximately 85 g of enzyme granules were premixed with 10 kg of feed for 10 minutes in a small horizontal mixer. This premix was then mixed with 190 kg of feed for 10 minutes in a larger horizontal mixer. From the mixer, the feed was fed to the conditioner (a steam-injected cascade mixer) at a rate of approximately 300 kg / hour. The conditioner heated the feed to 85 °C, 90 °C, and cz i znn / Lznz / E / YiAi °C, respectively (measured at the outlet) by steam injection. The residence time in the conditioner also varied from 60 seconds to 120 seconds. From the conditioner, the feed was fed to a Simon Heesen press equipped with a 3.0 x 35 mm horizontal die and pressed into pellets approximately 15 mm long. After pressing, the pellets were placed in an air cooler and cooled for 15 minutes. Feed formulation: 73.0% ground corn 21.5% toasted soy semolina 4.0% soybean oil Farmix VLSVRK 0.5% Vitamin / Premix Water content of the feed: 12% and 14%, respectively. The activity of the incoming enzyme granules and the activities of the final pellets were analyzed, and from these figures the residual activity was calculated. Results of the pelleting test with 12°s moisture in the feed: cz i znn / Lznz / E / YiAi % of residual activity Formulation Comprises Coating 90°C / 60 s 90°C / 120s Product 1 Granule 1 Layer of 40% Na2SO4 75 71 Product 2 Granule 2 Inner layer of 40% Na2SO4 + outer layer of hydrolyzed palm oil 83 84 Results of the pelleting test with 14% moisture in the feed: % of residual activity Ί 0 Formulation Comprises Coating 90 °C / 60 s 90°C / 120s Product 1 Granule 1 Layer of 40% Na2SO4 77 49 Product 2 Granule 2 Inner layer of 40% Na2SO4 + outer layer of hydrolyzed palm oil 83 68 Results of the pelleting test with 14% moisture in the feed and different temperatures: 20% residual activity Formulation Comprises Coating 85°C / 60 s 90°C / 60 s 95°C / 60 s Product 1 Granule 1 Layer of 40% Na2SO4 75 66 36 Product 2 Granule 2 Inner layer of 40% Na2SO4 + outer layer of hydrolyzed palm oil 89 77 49 Based on the results, it is evident that the combination of an internal salt layer and an external hydrophobic layer significantly improves pelleting stability when the moisture content in the feed increases compared to a salt coating alone. Example 2 Granule 3, granule comprising a core comprising a muramidase, and a salt layer in the core: A powder mixture with the following composition 960 g of cellulose, Arbocel BC200 600 g of dextrin, kaolin 2534 g of spray-dried GH25 muramidase powder 7552 g of ground Na2SCu was granulated in a Lódige FM 50 mixer with a granulation liquid consisting of 480 g of sucrose 2220 g of water The granulation process was described in US patent 4,106,991, example 1. The resulting granules were dried in a fluid bed dryer to a water content of less than 1% and sieved to obtain a product with a particle size between 250 and 1200 micrometers. 4.0 kg of the granule nuclei described above cz i znn / Lznz / E / YiAi were placed in a fluidized bed MP1. The following mixture was prepared to apply a layer of salt to the cores: 2000 g of Na2S4 5000 g of water The following bed placement was used during coating: Airflow: 215 m3 / hour Inlet temperature 90 °C Product temperature: 44 °C Nozzle size: 1.2 mm Nozzle pressure: 3.0 bar After coating, the granules were dried for 10 min. to reach a temperature of 75 °C and finally cooled. Granule 4, granule comprising a core comprising muramidase, an inner salt layer in the core and an outer hydrophobic layer in the inner salt layer. 2.0 kg of granule 3 were placed in a Lódige L 5 mixer. The following mixture was prepared to apply a hydrophobic layer to the salt layer: g melted hydrogenated palm oil 120 g of kaolin After coating, the final product was cooled in a fluidized bed MP 2. Granule 5, granule comprising a core comprising muramidase, an inner salt layer in the core and an outer hydrophobic layer in the inner salt layer. A powder mixture with the following composition 960 g of cellulose, Arbocel BC200 600 g of dextrin, kaolin 2534 g of spray-dried GH25 muramidase powder 7552 g of ground Na2SO4 was granulated in a Lódige FM 50 mixer with a granulation liquid consisting of 480 g of sucrose 2220 g of water The granulation process was described in US patent 4,106,991, example 1. The resulting granules were dried in a fluid bed dryer to a water content of less than 1% and sieved to obtain a product with a particle size between 250 and 1200 micrometers. 4.0 kg of the granule cores described above were placed in an MP1 fluidized bed. The following mixture was prepared to apply a layer of salt to the cores: 2400 g of Na2SO4 6000 g of water The following bed placement was used during the cz i znn / Lznz / E / γΐΛΐ coating: Airflow: 215 m3 / hour Inlet temperature 90 °C Product temperature: 44 °C Nozzle size: 1.2 mm Nozzle pressure: 3.0 bar After coating, the granules were dried for 10 min. to reach a temperature of 75 °C and finally cooled. Granule 6, granule comprising a core comprising muramidase, an inner salt layer in the core and an outer hydrophobic layer in the inner salt layer. 2.0 kg of granule 5 were placed in a Lódige L 5 mixer. The following mixture was prepared to apply a hydrophobic layer to the salt layer: g melted hydrogenated palm oil 120 g of kaolin After coating, the final product was cooled in an MP 2 fluid bed. Pelletization stability Products 1, 2, 3, 4 and 6 comprising granules 1, 2, 3, 4 and 6 respectively were pelleted under the conditions given in Example 1 with a higher water content in the feed of 14%. cz i znn / Lznz / E / γΐΛΐ % of residual activity Formulation Comprises Coating 90 °C / 60 s Product 1 Granule 1 Layer of 40% Na2SO4 77 Product 2 5 Granule 2 Inner layer of 40% Na2SO4 + outer layer of hydrolyzed palm oil 83 Product 3 Granule 3 Layer of 50% Na2SO4 76 Product 4 10 Granule 4 Inner layer of 50% Na2SO4 + outer layer of hydrolyzed palm oil 85 Product 6 Granule 6 Inner layer of 60% Na2SO4 + outer layer of hydrolyzed palm oil 94 Pelletizing test results with 14% moisture in the feed and different temperatures: % of residual activity Formulation Comprises Coating 90 °C / 60 s 95 °C / 60 s Product 3 Granule 3 50% Na2SO4 layer 76 76 Product 4 Granule 4 50% Na2SO4 inner layer + hydrazine palm oil outer layer 85 79 Product 6 Granule 6 60% Na2SO4 inner layer + hydrazine palm oil outer layer 94 94 From the experiments, it is clear that a greater salt coating significantly increases pelleting stability, and stability increases even more with the addition of an external hydrophobic layer of palm oil. It is hereby stated that, as of this date, the best method known to the applicant for putting the aforementioned invention into practice is the one that is clear from the present description of the invention.

Claims

1. A pelleted feed composition characterized in that it comprises a granule comprising a core and a coating, wherein the core comprises a muramidase and the coating comprises an internal salt layer and an external hydrophobic layer.

2. The feed composition according to claim 1, characterized in that it has been exposed to steam treatment.

3. The feed composition according to claim 1 or 2, characterized in that the internal salt layer contributes between 30-60% w / w of the granule, such as 40-60% w / w.

4. The feed composition according to any of claims 1 to 3, characterized in that the internal salt layer comprises Na2SO4, K2SO4, MgSO4 or a mixture thereof.

5. The feed composition according to any of claims 1 to 4, characterized in that the outer hydrophobic layer contributes between 2-3% w / w of the granule.

6. The feed composition in accordance with any of claims 1 to 5, characterized in that the outer hydrophobic layer comprises hydrogenated palm oil.

7. The feed composition according to any of claims 1 to 6, characterized in that the muramidase is a GH25 muramidase having the ability to lyse bacterial cell walls.

8. The feed composition according to any of claims 1 to 7, characterized in that the moisture content of the feed composition is at least 11% before pelleting and conditioning.

9. The feed composition according to any of claims 1 to 8, characterized in that the retained muramidase activity present in the core of the pellets after steam pelleting at 85 degrees Celsius is at least 75% of the muramidase activity in the core of the pellets before steam pelleting.

10. A granule characterized in that it comprises a core and a coating, wherein the core comprises a muramidase and the coating comprises an internal salt layer and an external hydrophobic layer.

11. A granule characterized in that it comprises a core and a coating, wherein the core comprises a muramidase and the coating comprises an internal salt layer and an external hydrophobic layer, wherein the granule comprises at least 75% muramidase with retained activity after steam pelletizing compared to the activity before steam pelletizing, and wherein the granule further comprises one or more of the following: i. the particle size of the granule is less than 1200 pm, ii. the thickness of the internal salt layer is at least 15 pm, iii. the thickness of the external hydrophobic coating is at least 1 pm, and iv. the muramidase is thermolabile 12. A method for feeding animals characterized in that it comprises administering the feed composition according to any of claims 1 to 9 to an animal.

13. A method for manufacturing a feed composition characterized in that it comprises the following steps: (i) mixing feed components with pellets comprising a core, an inner coating and an outer coating wherein the core comprises a muramidase, the inner coating comprises a salt and the outer coating comprises a hydrophobic coating material, (ii) steam-treating the composition, and (iii) pelletizing the composition.

14. A method for improving the stability of cz i znn / Lznz / E / γΐΛΐ muramidase characterized in that it comprises incorporating the muramidase into a feed composition according to any one of claims 1 to 9 or a granule according to any one of claims 10 to 11. 5 15. A method for improving the stability of muramidase in a feed composition having a moisture content greater than 12%, characterized in that it comprises incorporating the muramidase into a feed composition according to any one of claims 1 to 9 or a granule according to any one of claims 10 to 11.

16. Use of a granule comprising a core comprising a muramidase, an inner salt layer and an outer hydrophobic layer according to any of claims 10 to 11 for preparing steam-treated pelleted feed compositions.