Bran fermented biological feed and preparation method thereof

Abstract

The invention discloses a bran fermented biological feed and a preparation method thereof, and belongs to the technical field of feeds. The bran fermented biological feed is prepared by uniformly mixing and fermenting the following raw materials: wheat bran, corn flour, soybean meal, calcium hydrogen phosphate, sodium chloride, an enzyme preparation, a water retention setting agent, a mildew preventive and water, wherein the enzyme preparation is prepared from lactobacillus plantarum, bacillus subtilis and saccharomycetes; the mildew preventive is prepared by the following steps: reacting chitosan oligosaccharide with propiolic acid to obtain modified chitosan oligosaccharide, reacting L-cystine with ethyl azidoacetate to obtain an azide compound, and finally reacting the modified chitosan oligosaccharide with the azide compound. The prepared bran fermented biological feed has an excellent mildew-proof effect and a low pulverization rate, and storage and transportation of the feed are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of feed, in particular to a bran fermented biological feed and a preparation method thereof. Background Art

[0002] Bran, the outermost layer of wheat, is a byproduct of flour processing. It contains a wealth of dietary fiber, protein, vitamins, and minerals, making it a high-quality feed ingredient. Fermentation significantly increases the content of active substances (such as amino acids and lactic acid) in bran, enhancing its nutritional value and palatability. It also reduces the level of anti-nutritional factors in bran, improving the nutritional value of the feed and the animal's absorption efficiency. Pelleted feed is prone to pulverization during long-distance transportation and handling. Furthermore, it is susceptible to spoilage during long-term storage.

[0003] Chinese invention patent publication number CN104304686A discloses an additive for DDGS fermented feed, fermented feed, and its preparation method. The additive includes a composite bacterial strain, mesophilic amylase, and a strong base. DDGS is fermented using microorganisms. Through microbial metabolism, the microorganisms can degrade crude fiber and non-starch polysaccharides in DDGS, increasing protein content and breaking down protein macromolecules into easily absorbed small molecules such as peptides. However, its mildew resistance is limited. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the present invention aims to provide a bran fermented biological feed and a preparation method thereof.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions: A bran fermented biological feed is prepared by uniformly mixing and fermenting the following raw materials in parts by weight: Wheat bran: 60-70 parts, corn flour: 15-25 parts, soybean meal: 10-15 parts, calcium hydrogen phosphate: 0.5-1 part, sodium chloride: 0.5-0.8 part, enzyme preparation: 0.2-0.5 part, water-retaining setting agent: 0.8-1.2 parts, mildew inhibitor: 0.2-0.5 part, water: 60-80 parts; Wherein, the enzyme preparation is composed of Lactobacillus plantarum, Bacillus subtilis, and yeast; The mildew inhibitor is prepared by reacting chitosan oligosaccharide with propiolic acid to obtain modified chitosan oligosaccharide, reacting L-cystine with ethyl azidoacetate to obtain an azide compound, and finally reacting the modified chitosan oligosaccharide with the azide compound.

[0006] The enzyme preparation is composed of plant lactobacillus, bacillus subtilis and yeast in a mass ratio of 1.5:(0.5-1):(0.8-1).

[0007] The mildew inhibitor is prepared by the following method: S1: Under nitrogen protection, chitosan oligosaccharide and propiolic acid react in the presence of N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride to obtain modified chitosan oligosaccharide; the reaction equation is shown below:

[0008] Among them, m=o+p.

[0009] S2: L-cystine reacts with ethyl azidoacetate to produce an azide compound; the reaction equation is shown below:

[0010] S3: Modified chitosan oligosaccharide reacts with azide compounds under the catalysis of copper sulfate and ascorbic acid to prepare a mildew inhibitor; the reaction equation is as follows:

[0011] The mass ratio of chitosan oligosaccharide to propiolic acid in step S1 is 15:(3-4).

[0012] The molar ratio of L-cystine to ethyl azidoacetate in step S2 is (1-1.2):2.

[0013] The mass ratio of the modified chitosan oligosaccharide and the azide compound in step S3 is 20:(3-4).

[0014] The water-retaining setting agent is prepared by the following method: N1: Dopamine reacts with 1,6-hexamethylene diisocyanate to obtain a hydroxy compound; the reaction equation is as follows:

[0015] N2: The hydroxy compound reacts with sodium alginate to form a water-retaining setting agent, wherein the sodium carboxylate group of the sodium alginate and the hydroxyl group of the hydroxy compound undergo an esterification reaction under the action of a catalyst.

[0016] The molar ratio of dopamine to hexamethylene diisocyanate is 2:1.

[0017] The mass ratio of the hydroxy compound to sodium alginate is 1:15.

[0018] A method for preparing bran fermented biological feed comprises the following steps: (1) Weigh by weight: wheat bran: 60-70 parts, corn flour: 15-25 parts, soybean meal: 10-15 parts, calcium hydrogen phosphate: 0.5-1 part, sodium chloride: 0.5-0.8 part, enzyme preparation: 0.2-0.5 part, water-retaining setting agent: 0.8-1.2 parts, mildew inhibitor: 0.2-0.5 part, water: 60-80 parts; (2) Wheat bran, corn flour, soybean meal, and enzyme preparation are stirred and mixed, water is added, stirred and mixed, and fermented at 20-40°C for 3 days to obtain a fermentation system; (3) Adding calcium hydrogen phosphate, sodium chloride, a water-retaining setting agent, and a mildew inhibitor into the above fermentation system, stirring evenly, granulating, and screening to obtain bran fermented biological feed.

[0019] Due to the adoption of the above technical solution, the beneficial effects of the present invention include: (1) The mildew inhibitor prepared by the present invention achieves mildew prevention effect by destroying the integrity of cell walls, changing the ion permeability of cell membranes and inhibiting the activity of enzymes in multiple ways.

[0020] (2) The water-retaining setting agent prepared by the present invention wraps and bonds the feed through the macromolecular network structure and hydrogen bonding, reduces the particle pulverization rate and maintains the internal humidity of the feed. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0022] Example 1 Preparation of mildew inhibitor S1: 1500 ml of anhydrous dimethyl sulfoxide and 30 g of propiolic acid were added to the reactor in sequence and stirred for 10 min. Then, 28 g of N-hydroxysuccinimide and 48 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added, the temperature was lowered to 0°C and stirred for 1 h, 150 g of chitosan oligosaccharide was added, the temperature was raised to 50°C, the reaction was continued for 6 h, the temperature was lowered to room temperature, and the mixture was distilled under reduced pressure at 60°C for 1 h. 300 g of anhydrous ethanol was added to precipitate the mixture, which was filtered and washed twice with anhydrous ethanol (200 ml each time). The mixture was dried under vacuum at 50°C for 10 h to obtain modified chitosan oligosaccharide. S2: In an ice bath, 500 ml of tetrahydrofuran, 50 ml of deionized water, and 0.1 mol of L-cystine were added to a reaction kettle and stirred. The pH was adjusted to 10 with 10 wt % sodium hydroxide solution, and 0.2 mol of ethyl azidoacetate was added dropwise over 20 min. The reaction was warmed to room temperature for 8 h. 800 ml of deionized water was added and stirred to precipitate. The mixture was filtered and washed three times with deionized water (200 ml each time). The mixture was dried under vacuum at 50°C for 12 h to obtain the azide compound. Its H NMR spectrum data are as follows: 1H NMR (300 MHz, DMSO-d6) δ7.59 (s, 2H), 7.25 (d, J = 7.8 Hz, 2H), 4.30 (dt, J = 7.7, 4.5 Hz, 2H), 4.21(d, J = 3.0 Hz, 2H), 4.01 (d, J = 2.9 Hz, 2H), 3.06 (dd, J = 13.2, 4.5 Hz, 2H), 2.81 (dd, J = 13.3, 4.5 Hz, 2H); S3: Add 1000 ml of deionized water, 200 g of modified chitosan oligosaccharide and 30 g of azide compound into a reactor, stir for 10 minutes, then add 60 ml of a deionized water solution containing 2 g of copper sulfate and 3 g of sodium ascorbate, stir at room temperature for 20 hours, add 1500 ml of anhydrous ethanol to precipitate, filter, wash twice with anhydrous ethanol (500 ml each time), and vacuum dry at 50°C for 10 hours to obtain a mildew inhibitor.

[0023] Example 2 Preparation of mildew inhibitor S1: 1500 ml of anhydrous dimethyl sulfoxide and 36 g of propiolic acid were added to the reactor in sequence and stirred for 10 min. Then, 28 g of N-hydroxysuccinimide and 48 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added, the temperature was lowered to 0°C and stirred for 1.5 h, 150 g of chitosan oligosaccharide was added, the temperature was raised to 55°C, the reaction was continued for 5 h, the reaction was cooled to room temperature, and the mixture was distilled under reduced pressure at 60°C for 1 h. 300 g of anhydrous ethanol was added to precipitate the mixture, which was filtered and washed twice with anhydrous ethanol (200 ml each time). The mixture was dried under vacuum at 50°C for 10 h to obtain modified chitosan oligosaccharide. S2: Under ice bath, add 500 ml of tetrahydrofuran, 50 ml of deionized water, and 0.11 mol of L-cystine to a reaction kettle, stir and mix, adjust the pH to 10 with 10 wt % sodium hydroxide solution, add 0.2 mol of ethyl azidoacetate dropwise, and complete the addition over 20 min. Warm the mixture to room temperature and react for 10 h. Add 800 ml of deionized water and stir to precipitate, filter, wash three times with deionized water (200 ml each time), and dry in vacuo at 50°C for 12 h to obtain an azide compound. S3: Add 1000 ml of deionized water, 200 g of modified chitosan oligosaccharide and 38 g of azide compound into a reactor, stir for 10 minutes, then add 60 ml of a deionized water solution containing 2 g of copper sulfate and 3 g of sodium ascorbate, stir at room temperature for 24 hours, add 1500 ml of anhydrous ethanol to precipitate, filter, wash twice with anhydrous ethanol (500 ml each time), and vacuum dry at 50°C for 10 hours to obtain a mildew inhibitor.

[0024] Example 3 Preparation of antifungal agent S1: 1500 ml of anhydrous dimethyl sulfoxide and 40 g of propiolic acid were added to the reactor in sequence and stirred for 10 min. Then, 28 g of N-hydroxysuccinimide and 48 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added, the temperature was lowered to 0°C and stirred for 2 h, 150 g of chitosan oligosaccharide was added, the temperature was raised to 60°C, the reaction was continued for 4 h, the reaction was cooled to room temperature, and the mixture was distilled under reduced pressure at 60°C for 1 h. 300 g of anhydrous ethanol was added to precipitate the mixture, which was filtered and washed twice with anhydrous ethanol (200 ml each time). The mixture was vacuum dried at 50°C for 10 h to obtain modified chitosan oligosaccharide. S2: Under ice bath, add 500 ml of tetrahydrofuran, 50 ml of deionized water, and 0.12 mol of L-cystine to a reactor, adjust the pH to 10 with 10 wt% sodium hydroxide solution, add 0.2 mol of ethyl azidoacetate dropwise for 20 min, warm to room temperature and react for 12 h, add 800 ml of deionized water and stir to precipitate, filter, wash three times with deionized water (200 ml each time), and dry in vacuo at 50°C for 12 h to obtain the azide compound; S3: Add 1000 ml of deionized water, 200 g of modified chitosan oligosaccharide and 40 g of azide compound into a reactor, stir for 10 minutes, then add 60 ml of a deionized water solution containing 2 g of copper sulfate and 3 g of sodium ascorbate, stir at room temperature for 30 hours, add 1500 ml of anhydrous ethanol to precipitate, filter, wash twice with anhydrous ethanol (500 ml each time), and vacuum dry at 50°C for 10 hours to obtain a mildew inhibitor.

[0025] Example 4 Preparation of water-retaining setting agent N1: Place 800 ml of tetrahydrofuran, 1 mol of dopamine, and 1.5 mol of triethylamine in a reaction kettle, stir and mix thoroughly, cool to 0°C, and dropwise add 100 ml of a tetrahydrofuran solution containing 0.5 mol of 1,6-hexamethylene diisocyanate. Add the solution over a period of 1 hour. Warm the mixture to room temperature and react for 18 hours. Wash the mixture three times with saturated brine (300 ml each time), and distill under reduced pressure at 40°C for 2 hours to obtain a hydroxy compound. Its H NMR spectrum data are as follows: 1 H NMR (300 MHz, DMSO-d6) δ 7.46 (s, 2H), 6.77 – 6.63 (m, 4H), 6.51 (dt, J = 1.9, 1.0 Hz, 2H), 6.01 (t, J = 4.8 Hz, 2H), 5.85 – 5.75 (m, 4H),3.35 – 3.24 (m, 4H), 3.08 (td, J = 5.7, 4.8 Hz, 4H), 2.84 – 2.74 (m, 4H),1.58 – 1.43 (m, 4H), 1.37 – 1.25 (m, 4H); N2: Add 700 ml of DMF, 800 ml of formamide, and 8 g of p-toluenesulfonic acid into a reactor, stir to mix, add 150 g of sodium alginate, heat to 60°C, stir for 30 min, add 15 g of 4-(N,N′-dimethylamino)pyridine, 12 g of N,N′-dicyclohexylcarbodiimide, and 50 g of a chloroform solution containing 10 g of a hydroxyl compound in sequence, react for 10 h, add 1500 ml of anhydrous ethanol, stir to precipitate, filter, wash three times with anhydrous ethanol (300 ml each time), and dry in a vacuum at 50°C for 12 h to obtain a water-retaining setting agent.

[0026] Example 5 Preparation of wheat bran fermented biological feed (1) Weigh: wheat bran: 6000 g, corn flour: 1500 g, soybean meal: 1000 g, calcium hydrogen phosphate: 50 g, sodium chloride: 50 g, enzyme preparation: 20 g, water-retaining setting agent (prepared in Example 1): 80 g, mildew inhibitor (prepared in Example 4): 20 g, water: 6000 g; The enzyme preparation consists of 10.7g of Lactobacillus plantarum, 3.5g of Bacillus subtilis, and 5.8g of yeast; (2) Wheat bran, corn flour, soybean meal, and enzyme preparation were stirred and mixed, water was added, stirred and mixed, and fermented at 20°C for 3 days to obtain a fermentation system; (3) Calcium hydrogen phosphate, sodium chloride, water-retaining setting agent and mildew inhibitor were added to the above fermentation system, stirred at a constant temperature of 20°C for 1 hour, dried by forced air at 50°C, and the moisture content was controlled at 15wt%. The system was pelletized using a ring die pelletizer (ring die aperture 3mm, compression ratio 1:8, ring die linear speed 6m / s, and the material temperature was adjusted to 70°C by steam conditioning), cooled to room temperature, and screened using a double-layer vibrating screen (the upper layer was 4mm to screen out oversized particles, and the lower layer was 2mm to screen out powder) to obtain bran fermented biological feed.

[0027] Example 6 Preparation of wheat bran fermented biological feed (1) Weigh: wheat bran: 6500g, corn flour: 2000g, soybean meal: 1400g, calcium hydrogen phosphate: 80g, sodium chloride: 60g, enzyme preparation: 40g, water-retaining setting agent (prepared in Example 2): 100g, mildew inhibitor (prepared in Example 4): 40g, water: 7000g; The enzyme preparation consists of 18.7g of Lactobacillus plantarum, 10g of Bacillus subtilis, and 11.3g of yeast; (2) Wheat bran, corn flour, soybean meal, and enzyme preparation were stirred and mixed, water was added, stirred and mixed, and fermented at 37°C for 3 days to obtain a fermentation system; (3) Calcium hydrogen phosphate, sodium chloride, water-retaining setting agent and mildew inhibitor were added to the above fermentation system, stirred at a constant temperature of 37°C for 1 hour, dried by forced air at 50°C, and the moisture content was controlled at 15wt%. The system was pelletized using a ring die pelletizer (ring die aperture 3mm, compression ratio: 1:8, ring die linear speed 6m / s, and the material temperature was brought to 70°C by steam conditioning), cooled to room temperature, and screened using a double-layer vibrating screen (the upper layer 4mm screened out oversized particles, the lower layer 2mm screened out powder) to obtain bran fermented biological feed.

[0028] Example 7 Preparation of wheat bran fermented biological feed (1) Weigh: wheat bran: 7000 g, corn flour: 2500 g, soybean meal: 1500 g, calcium hydrogen phosphate: 100 g, sodium chloride: 80 g, enzyme preparation: 50 g, water-retaining setting agent (prepared in Example 3): 120 g, mildew inhibitor (prepared in Example 4): 50 g, water: 8000 g; The enzyme preparation consists of 21.4g of Lactobacillus plantarum, 14.3g of Bacillus subtilis, and 14.3g of yeast; (2) Wheat bran, corn flour, soybean meal, and enzyme preparation were stirred and mixed, water was added, stirred and mixed, and fermented at 40°C for 3 days to obtain a fermentation system; (3) Calcium hydrogen phosphate, sodium chloride, water-retaining setting agent and mildew inhibitor were added to the above fermentation system, stirred at a constant temperature of 40°C for 1 hour, dried by forced air at 50°C, and the moisture content was controlled at 15wt%. The system was pelletized using a ring die pelletizer (ring die aperture 3mm, compression ratio: 1:8, ring die linear speed 6m / s, and the material temperature was adjusted to 70°C by steam conditioning), cooled to room temperature, and screened using a double-layer vibrating screen (the upper layer was 4mm to screen out oversized particles, and the lower layer was 2mm to screen out powder) to obtain bran fermented biological feed.

[0029] Comparative Example 1 The preparation method of the bran fermented biological feed is basically the same as that of Example 6, except that the mildew inhibitor (prepared in Example 2) in the components is replaced with an equal mass of chitosan oligosaccharide.

[0030] Comparative Example 2 The preparation method of the bran fermented biological feed is basically the same as that of Example 6, except that the mildew inhibitor (prepared in Example 2) in the components is replaced with a mildew inhibitor of equal mass prepared by the following method: The preparation method of the mildew inhibitor is substantially the same as that of Example 2, except that L-cystine in step S2 is replaced by an equimolar amount of hexamethylenediamine.

[0031] Comparative Example 3 The preparation method of the bran fermented biological feed is basically the same as that of Example 6, except that the mildew inhibitor (prepared in Example 2) in the components is replaced with a mildew inhibitor of equal mass prepared by the following method: To the reactor, 1500 ml of anhydrous dimethyl sulfoxide and 36 g of L-cystine were added in sequence and stirred for 10 minutes. Then, 28 g of N-hydroxysuccinimide and 48 g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were added, the temperature was lowered to 0°C and stirred for 1.5 hours, 150 g of chitosan oligosaccharide was added, the temperature was raised to 55°C, the reaction was continued for 5 hours, the mixture was cooled to room temperature, and the mixture was distilled under reduced pressure at 60°C for 1 hour. 300 g of anhydrous ethanol was added to precipitate the mixture, which was filtered, washed twice with anhydrous ethanol (200 ml each time), and dried in vacuo at 50°C for 10 hours to obtain the mildew inhibitor.

[0032] Comparative Example 4 The preparation method of the bran fermented biological feed is basically the same as that of Example 6, except that the water-retaining setting agent (prepared in Example 4) is replaced by an equal mass of sodium alginate.

[0033] Comparative Example 5 The preparation method of the bran fermented biological feed is basically the same as that of Example 6, except that the water-retaining and setting agent (prepared in Example 4) is replaced with a water-retaining and setting agent prepared by the following method: Add 700 ml of DMF, 800 ml of formamide, and 8 g of p-toluenesulfonic acid into a reactor, stir and mix, add 150 g of sodium alginate, heat to 60°C, stir for 30 min, add 15 g of 4-(N,N'-dimethylamino)pyridine, 12 g of N,N'-dicyclohexylcarbodiimide and 50 g of chloroform solution containing 10 g of dopamine in sequence, react for 10 h, add 1500 ml of anhydrous ethanol, stir to precipitate, filter, wash three times with anhydrous ethanol (300 ml each time), and dry in a vacuum at 50°C for 12 h.

[0034] The Lactobacillus plantarum used in the examples and comparative examples of this application (1×10 10 CFU / g), Bacillus subtilis (5×10 10 CFU / g), yeast (2×10 10 CFU / g) was produced by Weifang Ruichen Biotechnology Co., Ltd.; the molecular weight of chitosan oligosaccharide is 2000Da; the molecular weight of sodium alginate is Mw=2.85×10 5 .

[0035] The bran fermented biological feed prepared in Examples 5-7 and Comparative Examples 1-3 was tested for mildew resistance according to GB / T 13092-2006. The test method is as follows: The bran fermented biological feed prepared in the examples and comparative examples was crushed, 25 g was weighed, 225 ml of diluent was added, and the feed was placed in a mold incubator. The mold count of the feed was measured at 5 days, 10 days, 20 days, and 30 days. The test results are shown in Table 1.

[0036] The bran fermented bio-feed prepared in Examples 5-7 and Comparative Examples 1-5 was subjected to a Pellet Durability Index (PDI) test. The test method is as follows: Accurately weigh 100g of each of the above feed pellets and place them in a dedicated rotary pulverizer. Set the rotation speed to 50 rpm for 10 minutes. After the rotation is complete, sieve through a 2mm standard sieve. Collect the oversize (unpulverized particles) and weigh them. Using the formula PDI = (oversize mass / initial sample mass) × 100%, repeat the measurement three times and take the average value as the test result. The test results are shown in Table 1.

[0037] The bran fermented biological feed prepared in Examples 5-7 and Comparative Examples 1-5 was tested for water retention, and the test method was as follows: Weigh 100g of sample into a weighing dish, spread it evenly, and place it in an oven preheated to 90℃ for 30min (starting from the time the temperature reaches the standard). Cool it and weigh it, and calculate the water loss rate: water loss rate = (100-weight after drying) / 100×100%; the water loss rate of each group of samples was measured 3 times and the average was taken; the test results are shown in Table 1.

[0038] Table 1 Performance test table

[0039] It can be seen from the data of Examples 5, 6 and 7 in Table 1 that the bran fermented biological feed prepared by the present invention has excellent mildew resistance and low pulverization rate, which is beneficial to the storage and transportation of feed.

[0040] The antifungal agent prepared by this invention incorporates positively charged amino groups introduced through chitosan oligosaccharides, which can bind to negatively charged groups on the fungal cell wall, thereby destroying the integrity of the cell wall and altering the ion permeability of the cell membrane, leading to the death of the fungus. The triazole structure and disulfide bond structures in the antifungal agent inhibit enzyme activity, impairing the integrity of the cell membrane and, in turn, affecting the growth and reproduction of the fungus. The thiol (-SH) cleavage product of the disulfide bond can bind to key enzymes within microorganisms, thereby enhancing the antifungal effect. Furthermore, the chitosan oligosaccharides and L-cystine produced by the decomposition of the antifungal agent are non-toxic to animals.

[0041] The water-retaining setting agent prepared by the present invention is based on sodium alginate, which reacts to form a network macromolecular structure. During the feed pelleting process, it can bind to feed raw materials such as starch and protein, reducing the powdering rate of feed pellets. The water-retaining setting agent contains a large number of carboxyl groups, hydroxyl groups, ether bonds and amide bonds, which can enhance the adhesion performance by hydrogen bonding with the surface of feed raw materials such as starch and protein, and can also bind to water molecules through hydrogen bonding, so that the feed slowly releases water in a dry environment and maintains the internal humidity of the feed. In addition, the unreacted phenolic hydroxyl groups in dopamine can H +Release, promote the capture of free radicals; delay the oxidative deterioration of feed.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. However, any equivalent changes, modifications and evolutions made by ordinary technicians in this field without departing from the scope of the technical solution of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. A bran fermented biological feed, characterized in that: The following raw materials are mixed and fermented uniformly: Wheat bran: 60-70 parts, corn flour: 15-25 parts, soybean meal: 10-15 parts, calcium hydrogen phosphate: 0.5-1 part, sodium chloride: 0.5-0.8 part, enzyme preparation: 0.2-0.5 part, water-retaining setting agent: 0.8-1.2 parts, mildew inhibitor: 0.2-0.5 part, water: 60-80 parts; Wherein, the enzyme preparation is composed of Lactobacillus plantarum, Bacillus subtilis, and yeast; The mildew inhibitor is prepared by reacting chitosan oligosaccharide with propiolic acid to obtain modified chitosan oligosaccharide, reacting L-cystine with ethyl azidoacetate to obtain an azide compound, and finally reacting the modified chitosan oligosaccharide with the azide compound.

2. The bran fermented biological feed according to claim 1, characterized in that: The enzyme preparation is composed of plant lactobacillus, bacillus subtilis and yeast in a mass ratio of 1.5:(0.5-1):(0.8-1).

3. The bran fermented biological feed according to claim 1, characterized in that: The mildew inhibitor is prepared by the following method: S1: Under nitrogen protection, chitosan oligosaccharide and propiolic acid react in the presence of N-hydroxysuccinimide and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride to obtain modified chitosan oligosaccharide; S2: L-cystine reacts with ethyl azidoacetate to produce an azide compound; S3: The modified chitosan oligosaccharide reacts with azide compounds under the catalysis of copper sulfate and ascorbic acid to prepare a mildew inhibitor.

4. The bran fermented biological feed according to claim 3, characterized in that: The mass ratio of chitosan oligosaccharide to propiolic acid in step S1 is 15:(3-4).

5. The bran fermented biological feed according to claim 3, characterized in that: The molar ratio of L-cystine to ethyl azidoacetate in step S2 is (1-1.2):

2.

6. The bran fermented biological feed according to claim 3, characterized in that: The mass ratio of the modified chitosan oligosaccharide and the azide compound in step S3 is 20:(3-4).

7. The bran fermented biological feed according to claim 1, characterized in that: The water-retaining setting agent is prepared by the following method: N1: Dopamine reacts with 1,6-hexamethylene diisocyanate to obtain a hydroxy compound; N2: Hydroxyl compounds react with sodium alginate to form a water-retaining setting agent.

8. The bran fermented biological feed according to claim 7, characterized in that: The molar ratio of dopamine to hexamethylene diisocyanate is 2:

1.

9. The bran fermented biological feed according to claim 7, characterized in that: The mass ratio of the hydroxy compound to sodium alginate is 1:

15.

10. A method for preparing the bran fermented biological feed according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Weigh by weight: wheat bran: 60-70 parts, corn flour: 15-25 parts, soybean meal: 10-15 parts, calcium hydrogen phosphate: 0.5-1 part, sodium chloride: 0.5-0.8 part, enzyme preparation: 0.2-0.5 part, water-retaining setting agent: 0.8-1.2 parts, mildew inhibitor: 0.2-0.5 part, water: 60-80 parts; (2) Wheat bran, corn flour, soybean meal, and enzyme preparation are stirred and mixed, water is added, stirred and mixed, and fermented at 20-40°C for 3 days to obtain a fermentation system; (3) Adding calcium hydrogen phosphate, sodium chloride, a water-retaining setting agent, and a mildew inhibitor into the above fermentation system, stirring evenly, granulating, and screening to obtain bran fermented biological feed.

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