High-acid-soluble-protein soybean meal leavening agent, soybean meal and preparation method and application of soybean meal

Abstract

The invention belongs to the technical field of soybean meal fermentation, and particularly relates to a leavening agent of high-acid-soluble-protein soybean meal, soybean meal as well as a preparation method and application of the soybean meal. The leavening agent is formed by compounding candida utilis yeast powder and bacillus pumilus powder according to the equal mass ratio, the total bacterial count of the leavening agent is 350-4 billion / g, and the soybean meal with high acid soluble protein is obtained by fermenting the leavening agent in parts by weight, the feed is prepared from the following raw materials in parts by weight: 5-10 parts of glucose, 0.5-1.2 parts of compound vitamins, 0.5-1.2 parts of compound minerals, 80-90 parts of soybean meal, 1-3 parts of the leavening agent in claim 1 and 3-6 parts of yeast extract. According to the leavening agent disclosed by the invention, the content of acid-soluble protein in the soybean meal is increased, and the soybean meal prepared from the leavening agent can remarkably increase the body length and weight of cherax quadricarinatus and has high nutrition.

Description

Technical Field

[0001] The invention belongs to the technical field of soybean meal fermentation, and particularly relates to a starter of high-acid-soluble protein soybean meal, soybean meal and a preparation method and application thereof. Background Art

[0002] With the rapid economic development and people's continuous pursuit of quality of life, people now have higher and higher requirements on the quality of aquatic products. Shrimp, as a common aquatic product, plays an important role in people's lives and improves people's quality of life.

[0003] Soybean meal is a byproduct of soybean processing. It has a protein content of 40% to 60%, a balanced amino acid composition, and is rich in oligosaccharides, minerals and vitamins. It is a high-quality, high-protein, low-fat plant protein source. However, despite its wide use in the feed and food industries, soybean meal also has some problems:

[0004] Anti-nutritional factors: Soybean meal contains a variety of anti-nutritional factors, such as trypsin inhibitors, glucosides, lectins, etc. These anti-nutritional factors interfere with the function of digestive enzymes in animals, thereby reducing the bioavailability of protein in soybean meal. This interference may cause gastrointestinal disorders in animals, manifested as digestive problems such as diarrhea, thereby reducing the nutritional value of soybean meal. The soy acid-soluble protein decomposed from soybean antigen protein is more conducive to animal intestinal absorption and reduces the occurrence of intestinal diseases. Therefore, it is of great significance to increase the acid-soluble protein content of fermented soybean meal. Summary of the invention

[0005] The object of the present invention is to provide a high acid-soluble protein soybean meal fermentation agent, soybean meal and a preparation method and application thereof, so as to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention adopts the following technical solution: In a first aspect, the present invention provides a fermentation agent for high acid-soluble protein soybean meal, comprising Candida utilis with a preservation number of ACCC 20060 ( Candida utilis ) powder and Bacillus pumilus with the deposit number of ACCC 04447 ( Bacillus pumilus ) The bacterial powders are compounded in equal mass ratios, and the total bacterial count of the starter is 35 to 40 billion per gram.

[0007] The present invention compounds Candida utilis and Bacillus pumilus in equal mass ratios. This bacterial strain combination can effectively degrade soybean antigen protein during the fermentation process and generate more acid-soluble protein, which not only increases the palatability of soybean meal, but also improves the nutritional value of soybean meal and the intestinal health of animals, thereby being more conducive to increasing the feed intake and growth of animals.

[0008] In a second aspect, the present invention provides the use of the fermentation agent in the fermentation preparation of high acid-soluble protein soybean meal.

[0009] In a third aspect, the present invention provides a high acid-soluble protein soybean meal, which is prepared from the following raw materials in parts by weight: 5-10 parts of glucose, 0.5-1.2 parts of complex vitamins, 0.5-1.2 parts of complex minerals, 80-90 parts of soybean meal, 1-3 parts of the starter, and 3-6 parts of yeast extract.

[0010] Furthermore, calculated by weight, the vitamin complex comprises: 25~40 parts of vitamin A, 60~80 parts of vitamin E, 1~3 parts of vitamin D, 15~25 parts of vitamin B1, 1~2 parts of vitamin B2, 20~40 parts of vitamin PP, 5~10 parts of calcium pantothenate, 50~60 parts of vitamin B6, 4~5 parts of vitamin B12, 0.1~0.15 parts of biotin, 2~5 parts of folic acid, and 200~300 parts of vitamin C.

[0011] Furthermore, the composite mineral composition is calculated by weight: 15-20 parts of copper sulfate, 60-130 parts of ferrous sulfate, 20-60 parts of zinc sulfate, 0.1-1 parts of sodium selenite, 15-30 parts of potassium dihydrogen phosphate, and 10-20 parts of sodium dihydrogen phosphate.

[0012] In a fourth aspect, the present invention provides a method for preparing the high acid-soluble protein soybean meal, comprising the following steps: S1. Weigh 5-10 parts of glucose, 0.5-1.2 parts of multivitamins, 0.5-1.2 parts of multiminerals, 80-90 parts of soybean meal, 1-3 parts of the starter, and 3-6 parts of yeast extract according to weight; S2, crushing and sterilizing the soybean meal, and mixing the obtained soybean meal powder with an equal mass of water to obtain a material to be fermented; S3, adding glucose and yeast extract to the fermented material, stirring for 20-25 minutes, and obtaining primary treated soybean meal; S4, adding a fermentation agent to the primary treated soybean meal, stirring for 18-20 minutes, and fermenting for 45-48 hours at 22-25° C. and 60%-70% humidity to obtain primary fermented soybean meal; S5. Stir the complex vitamins and complex minerals with the primary fermented soybean meal for 30-35 minutes, and ferment them at a constant temperature and humidity of 30-35° C. and 60-70% for 20-24 hours to obtain the final fermented soybean meal, i.e., the high acid-soluble protein soybean meal.

[0013] In a fifth aspect, the present invention provides use of the fermentation agent in preparing feed.

[0014] In a sixth aspect, the present invention provides the use of the high acid-soluble protein soybean meal in preparing feed.

[0015] Furthermore, the feed is a feed for red claw crayfish farming.

[0016] The beneficial effects of the present invention are: The fermentation agent of the invention utilizes the growth characteristics of Candida utilis and Bacillus pumilus, and the two cooperate with each other to improve the utilization value of solid soybean meal fermented feed.

[0017] The preparation method of high acid-soluble protein soybean meal of the present invention adopts Candida utilis + Bacillus pumilus + segmented fermentation technology to ferment soybean meal, firstly adopts Candida utilis and Bacillus pumilus to preliminarily ferment soybean meal to reduce anti-nutritional factors and soybean meal toxicity in soybean meal, improve the palatability, appetizing property and nutrition of soybean meal, and then adds a certain amount of multivitamin to the fermentation product in the segmented fermentation process, aiming to further improve the nutrition of soybean meal. The present invention finally uses the prepared soybean meal for the feeding of red claw crayfish, and after testing, the produced soybean meal can significantly increase the body length and weight of red claw crayfish, and has extremely high nutrition. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a statistical chart of the test results of fermented soybean meal indicators.

[0019] Figure 2 This is a statistical chart of the test results of red claw crayfish breeding indicators.

[0020] Figure 3 The figures are the weighing results of the final weight of a single red claw crayfish randomly selected from each group. AF are Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, and Control Example 1 respectively.

[0021] Figure 4 The figures are the weighing results of ten red claw crayfish randomly selected from each group. AF are Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, and Control Example 1 respectively. DETAILED DESCRIPTION

[0022] The present invention is described in detail below in conjunction with the accompanying drawings and specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the following examples are conventional means well known to those skilled in the art, and the materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained from commercial sources.

[0023] The sources of the following bacteria are: Candida utilis: Candida utilis ( Candida utilis); from China Agricultural Microbiological Culture Collection Center, strain number: ACCC 20060.

[0024] Bacillus pumilus: Bacillus pumilus C-3 ( Bacillus pumilus ); from China Agricultural Microbiological Culture Collection Center, strain number: ACCC 04447.

[0025] The multivitamin composition used below is: 30 parts of vitamin A, 80 parts of vitamin E, 2 parts of vitamin D, 20 parts of vitamin B1, 2 parts of vitamin B2, 30 parts of vitamin PP, 5 parts of calcium pantothenate, 50 parts of vitamin B6, 4 parts of vitamin B12, 0.1 parts of biotin, 2 parts of folic acid, and 300 parts of vitamin C.

[0026] The mineral complex used below is composed of: 15 parts of copper sulfate, 80 parts of ferrous sulfate, 40 parts of zinc sulfate, 0.5 parts of sodium selenite, 20 parts of potassium dihydrogen phosphate, and 10 parts of sodium dihydrogen phosphate.

[0027] Example 1 The starter of this embodiment is a mixture of Candida utilis powder and Bacillus pumilus C-3 powder in an equal mass ratio, wherein the total bacterial count of the Candida utilis powder is 20 billion / gram, and the total bacterial count of the Bacillus pumilus C-3 powder is 20 billion / gram.

[0028] The fermented soybean meal of this embodiment is prepared from the following raw materials by weight: 5 parts of glucose, 0.5 parts of multivitamins, 0.5 parts of multiminerals, 90 parts of soybean meal, 1 part of starter, and 3 parts of yeast extract.

[0029] The fermented soybean meal of this embodiment is prepared by the following steps: S1. Grind soybean meal through a 60-mesh sieve to obtain soybean meal powder, sterilize the soybean meal powder at 120° C. for 30 min to obtain sterilized soybean meal powder, add water to the sterilized soybean meal powder at a mass ratio of 1:1, mix and stir to obtain a material to be fermented; S2, adding glucose and yeast extract to the material to be fermented, and fully stirring for 25 minutes to obtain primary treated soybean meal; S3, adding composite probiotic powder to the primary treated soybean meal, stirring thoroughly for 20 minutes, and fermenting under constant temperature and humidity conditions of 25° C. and 60% humidity for 48 hours to obtain primary fermented soybean meal; S4, preparation of a vitamin mixture: weighing each raw material according to the weight ratio of the vitamin mixture, and mixing them evenly to obtain a vitamin mixture; S5. Preparation of the mineral element mixture: weighing various raw materials according to the weight ratio of the mineral element mixture, and mixing them evenly to obtain the mineral element mixture; S6, fully stirring the vitamin mixture, the mineral mixture, and the primary fermented soybean meal for 30 minutes, and fermenting them under constant temperature and humidity conditions of 35° C. and 60% humidity for 24 hours to obtain the final fermented soybean meal; S7. Dry the fermented soybean meal at a constant temperature of 50°C and seal it for storage before use.

[0030] The sealed feed is tested for indicators.

[0031] Example 2 The starter of this embodiment is a mixture of Candida utilis powder and Bacillus pumilus C-3 powder in an equal mass ratio, wherein the total bacterial count of the Candida utilis powder is 20 billion / gram, and the total bacterial count of the Bacillus pumilus C-3 powder is 15 billion / gram.

[0032] The fermented soybean meal of this embodiment is prepared from the following raw materials by weight: 10 parts of glucose, 1.2 parts of multivitamins, 1.2 parts of multiminerals, 80 parts of soybean meal, 1.6 parts of starter, and 6 parts of yeast extract.

[0033] The fermented soybean meal of this embodiment is prepared by the following steps: S1. Grind soybean meal through a 50-mesh sieve to obtain soybean meal powder, sterilize the soybean meal powder at 125° C. for 30 min to obtain sterilized soybean meal powder, add water to the sterilized soybean meal powder at a mass ratio of 1:1, mix and stir to obtain a material to be fermented; S2, adding glucose and yeast extract to the material to be fermented, and fully stirring for 25 minutes to obtain primary treated soybean meal; S3, adding the composite probiotic powder to the primary treated soybean meal, stirring thoroughly for 20 minutes, and fermenting it under constant temperature and humidity conditions of 22° C. and 70% humidity for 48 hours to obtain primary fermented soybean meal; S4, preparation of a vitamin mixture: weighing each raw material according to the weight ratio of the vitamin mixture, and mixing them evenly to obtain a vitamin mixture; S5. Preparation of the mineral element mixture: weighing various raw materials according to the weight ratio of the mineral element mixture, and mixing them evenly to obtain the mineral element mixture; S6, fully stirring the vitamin mixture, the mineral mixture, and the primary fermented soybean meal for 30 minutes, and fermenting them at a constant temperature and humidity of 30° C. and 70% humidity for 24 hours to obtain the final fermented soybean meal; S7. Dry the fermented soybean meal at a constant temperature of 60°C and seal it for storage before use.

[0034] The sealed feed is tested for indicators.

[0035] Example 3 The starter of this embodiment is a mixture of Candida utilis powder and Bacillus pumilus C-3 powder in an equal mass ratio, wherein the total bacterial count of the Candida utilis powder is 20 billion / gram, and the total bacterial count of the Bacillus pumilus C-3 powder is 15 billion / gram.

[0036] The fermented soybean meal of this embodiment is prepared from the following raw materials by weight: 6 parts of glucose, 1 part of multivitamins, 1 part of multiminerals, 85 parts of soybean meal, 3 parts of starter, and 4 parts of yeast extract.

[0037] The fermented soybean meal of this embodiment is prepared by the following steps: S1. Grind soybean meal through a 50-mesh sieve to obtain soybean meal powder, sterilize the soybean meal powder at 120° C. for 30 min to obtain sterilized soybean meal powder, add water to the sterilized soybean meal powder at a mass ratio of 1:1, mix and stir to obtain a material to be fermented; S2, adding glucose and yeast extract to the material to be fermented, and fully stirring for 25 minutes to obtain primary treated soybean meal; S3, adding composite probiotic powder to the primary treated soybean meal, stirring thoroughly for 20 minutes, and fermenting under constant temperature and humidity conditions of 25° C. and 60% humidity for 48 hours to obtain primary fermented soybean meal; S4, preparation of a vitamin mixture: weighing each raw material according to the weight ratio of the vitamin mixture, and mixing them evenly to obtain a vitamin mixture; S5. Preparation of a mineral element mixture: weighing various raw materials according to the weight ratio of the mineral element mixture, and mixing them evenly to obtain a mineral element mixture; S6, fully stirring the vitamin mixture, the mineral mixture, and the primary fermented soybean meal for 30 minutes, and fermenting them under constant temperature and humidity conditions of 35° C. and 60% humidity for 24 hours to obtain the final fermented soybean meal; S7. Dry the fermented soybean meal at a constant temperature of 50°C and seal it for storage before use.

[0038] The sealed feed is tested for indicators.

[0039] Comparative Example 1 The fermentation agent of this comparative example has Candida utilis powder as the only ingredient, and the total bacterial count of Candida utilis powder is 20 billion / g. The fermented soybean meal of this comparative example is prepared from the following raw materials: 6 parts of glucose, 1 part of multivitamins, 1 part of multiminerals, 85 parts of soybean meal, 3 parts of starter, and 4 parts of yeast extract.

[0040] The preparation method of the fermented soybean meal in this comparative example is the same as that in Example 3.

[0041] Comparative Example 2 The fermentation agent of this comparative example is composed of Bacillus pumilus C-3 powder as the only component, and the total bacterial count of Bacillus pumilus C-3 powder is 20 billion / gram The fermented soybean meal of this comparative example is prepared from the following raw materials: 6 parts of glucose, 1 part of multivitamins, 1 part of multiminerals, 85 parts of soybean meal, 3 parts of starter, and 4 parts of yeast extract.

[0042] The preparation method of the fermented soybean meal in this comparative example is the same as that in Example 3.

[0043] Comparative Example 1 The fermented soybean meal of this comparative example is prepared from the following raw materials: 6 parts of glucose, 1 part of multivitamins, 1 part of multiminerals, 88 parts of soybean meal, 4 parts of yeast extract.

[0044] The preparation method of the fermented soybean meal in this comparative example is basically the same as that in Example 3, except that no fermentation agent is added.

[0045] In order to verify the effect of the fermentation agent and fermented soybean meal of the present invention, the following verification test was carried out: Breeding experiment Experimental design Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, and Control Example 1, a total of six groups, three replicates in each group, a total of 18 breeding water tanks, 40 shrimp fry in each breeding water tank, a total of 720. The breeding test lasted 56 days. Before the breeding test, the red claw crayfish was temporarily raised in the water circulation system of the laboratory for 7 days. The breeding box used in the experiment had a size of 1 m×2 m×1 m, a water depth of 0.7 m, and 15 PVC pipe shelters were placed in each breeding box. Aerated tap water and water plants such as aquatic plants were placed to create a natural ecological breeding environment. The water temperature was maintained at 25±0.5℃, and there was aeration and oxygenation. After the temporary breeding, young shrimps with uniform specifications, no broken limbs, no external symptoms, normal vitality and in the intermolting period were selected for breeding tests, and the initial body length was recorded. The daily feeding amount was about 6% of the shrimp body weight, which was adjusted according to the actual feeding situation of the red claw crayfish. It was fed twice a day, and the feeding time was 8:30 and 18:30. Before each feeding, the growth status of each shrimp in each group of tanks was observed and recorded. Feed was fed twice at each time point, with an interval of about 25 minutes between each feeding. The water was changed every morning after feeding, and the amount of water changed was 1 / 3 of the total water volume in the experimental breeding box, and the excrement of the red claw crayfish was sucked out.

[0046] The fermentation products of the embodiments, comparative examples and reference examples were tested for the following indicators: 1. pH value and total acid detection and analysis: (1) Take 10.00 g (accurate to 0.01 g) of fermented soybean meal sample; (2) Accurately measure 90 mL of sterile water, add it to the soybean meal sample, and extract at 4°C for 4 h; (3) Filter the extract before use; (4) Take 20 mL of the extract and add it to a 50 mL beaker for testing; (5) Use a calibrated pH meter to measure the pH of the fermentation extract and record the data; (6) Use 0.25 M sodium hydroxide standard solution to titrate the extract to pH 8.2, record the volume of alkali consumed, and calculate the total acid content.

[0047] To reduce errors, the tests were repeated three times.

[0048] The calculation formula is ; X is the total acid content in the sample, in g / kg; c is the concentration of the sodium hydroxide standard titration solution, in mol / L; V1 is the volume of the sodium hydroxide standard titration solution consumed when titrating the test solution, in mL; V2 is the volume of the sodium hydroxide standard titration solution consumed in the blank experiment, in mL; k is the conversion factor of the acid, which is 0.09 for lactic acid; F is the dilution multiple of the test solution; m is the mass of the sample, in g; 1000 is the conversion factor.

[0049] 2. Analysis of acid-soluble protein content: (1) Take 10g fermented soybean meal and put it into a kraft paper bag and dry it at 50℃ for 24h; (2) The dried soybean meal sample was crushed using a crusher and passed through an 80-mesh sieve; (3) Accurately weigh 50 mg (accurate to 0.0001 g) of the sieved soybean meal sample into a 2 mL centrifuge tube; (4) Add 5.0 mL of buffered extraction solution (50 mM Tris-HCl, containing 6 M urea and 0.2% sodium dodecyl sulfate, pH 9.5); (5) Ultrasonic-assisted extraction for 30 min, followed by constant temperature water bath extraction at 65 °C for 2 h; (6) Centrifuge at 12000 rpm for 20 min; (7) Take 100 μL of supernatant and add it to a 1.5 mL centrifuge tube, then add 100 μL of 10% trichloroacetic acid; (8) Add 800 μL of normal saline, spin at 14,000 rpm for 2 min, and take the supernatant to measure the acid-soluble protein content; (9) Use the BCA protein assay kit to detect and calculate the acid-soluble protein content.

[0050] To reduce errors, the tests were repeated three times.

[0051] The calculation formula is X (%) = sample concentration (concentration measured by the kit, mg / g) × V1 (extraction volume) / V2 (detection volume) / m (sample mass) × 100%.

[0052] 3. Body length and weight detection The initial body weight and initial body length were measured by randomly selecting 10 red claw crayfish from each group before the start of culture.

[0053] Final body weight and final body length On day 56 of culture, all red claw crayfish were fasted for 24 h, and 10 red claw crayfish were randomly selected from each group for measurement.

[0054] The results are shown in Table 1 and Figure 1 As shown, the use of Candida utilis and Bacillus pumilus to synergistically ferment soybean meal in the embodiments is beneficial to increasing the content of acid-soluble protein in the soybean meal during the fermentation process, wherein the total acid content of Example 1 is increased by 23.31% and the acid-soluble protein content is increased by 12.17% compared with Comparative Example 1, the total acid content of Example 1 is increased by 28.46% and the acid-soluble protein content is increased by 13.42% compared with Comparative Example 2, and the total acid content of Example 1 is increased by 48.12% and the acid-soluble protein content is increased by 38.01% compared with Control Example 1, thereby improving the utilization value of solid soybean meal fermented feed, reducing anti-nutritional factors in soybean meal and soybean meal toxicity, and improving the palatability, appetitiousness and nutritional value of soybean meal.

[0055] As shown in Table 2 and Figure 2 , Figure 3 As shown, the synergistic fermentation of soybean meal by Candida utilis and Bacillus pumilus in the embodiments is beneficial to increase the body length and weight of red claw crayfish during the breeding process, wherein the body length of red claw crayfish in Example 1 is increased by 12.42% and the weight of red claw crayfish is increased by 12.20% compared with Comparative Example 1, the body length of red claw crayfish in Example 1 is increased by 14.57% and the weight of red claw crayfish is increased by 15.39% compared with Comparative Example 2, the body length of red claw crayfish in Example 1 is increased by 25.46% and the weight of red claw crayfish is increased by 32.16% compared with Control Example 1, which significantly increases the body length and weight of red claw crayfish, and the fermented feed has high nutritional value.

[0056] Table 1 Test results of fermented soybean meal indicators Table 2 Test results of red claw crayfish breeding indicators It should be noted that when the claims of the present invention involve numerical ranges, it should be understood that the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. In order to avoid redundancy, the present invention describes a preferred embodiment.

[0057] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

Claims

1. A starter for high acid-soluble protein soybean meal, characterized in that: The Candida utilis with the deposit number ACCC 20060 ( Candida utilis ) powder and Bacillus brevis with the deposit number of ACCC 04447 ( Bacillus pumilus ) The bacterial powders are compounded in equal mass ratios, and the total bacterial count of the starter is 35 to 40 billion per gram.

2. Use of the starter culture according to claim 1 in fermenting and preparing high acid-soluble protein soybean meal.

3. A high acid-soluble protein soybean meal, characterized in that: The preparation method is based on the following raw materials by weight: 5-10 parts of glucose, 0.5-1.2 parts of complex vitamins, 0.5-1.2 parts of complex minerals, 80-90 parts of soybean meal, 1-3 parts of the starter according to claim 1, and 3-6 parts of yeast extract.

4. The high acid-soluble protein soybean meal according to claim 3, characterized in that: Calculated by weight, the vitamin complex consists of: 25~40 parts of vitamin A, 60~80 parts of vitamin E, 1~3 parts of vitamin D, 15~25 parts of vitamin B1, 1~2 parts of vitamin B2, 20~40 parts of vitamin PP, 5~10 parts of calcium pantothenate, 50~60 parts of vitamin B6, 4~5 parts of vitamin B12, 0.1~0.15 parts of biotin, 2~5 parts of folic acid, and 200~300 parts of vitamin C.

5. The high acid-soluble protein soybean meal according to claim 3, characterized in that: Calculated by weight, the composite mineral composition is: 15-20 parts of copper sulfate, 60-130 parts of ferrous sulfate, 20-60 parts of zinc sulfate, 0.1-1 parts of sodium selenite, 15-30 parts of potassium dihydrogen phosphate, and 10-20 parts of sodium dihydrogen phosphate.

6. The method for preparing the high acid-soluble protein soybean meal according to any one of claims 3 to 5, characterized in that: The following steps are involved: S1. Weigh 5-10 parts of glucose, 0.5-1.2 parts of multivitamins, 0.5-1.2 parts of multiminerals, 80-90 parts of soybean meal, 1-3 parts of the starter according to claim 1, and 3-6 parts of yeast extract according to weight; S2, crushing and sterilizing the soybean meal, and mixing the obtained soybean meal powder with an equal mass of water to obtain a material to be fermented; S3, adding glucose and yeast extract to the fermented material, stirring for 20-25 minutes, and obtaining primary treated soybean meal; S4, adding a fermentation agent to the primary treated soybean meal, stirring for 18-20 minutes, and fermenting for 45-48 hours at 22-25° C. and 60%-70% humidity to obtain primary fermented soybean meal; S5. Stir the complex vitamins and complex minerals with the primary fermented soybean meal for 30-35 minutes, and ferment them at a constant temperature and humidity of 30-35° C. and 60-70% for 20-24 hours to obtain the final fermented soybean meal, i.e., the high acid-soluble protein soybean meal.

7. Use of the fermentation agent according to claim 1 in preparing feed.

8. Use of the high acid-soluble protein soybean meal according to any one of claims 3 to 5 in preparing feed.

9. The use according to claim 8, characterized in that: The feed is a feed used for red claw crayfish breeding.

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