Fermentation type low-protein daily ration for pigs and production process thereof

Abstract

The invention discloses a fermented low-protein daily ration for pigs and a production process thereof, and relates to the technical field of microbial fermented feeds, the fermented low-protein daily ration comprises a compound bacteria solution, corn, soybean meal, wheat middling, sodium chloride, stone powder, cane molasses, calcium hydrophosphate, choline chloride and a premix, the compound bacterium liquid is prepared from corynebacterium glutamicum CICC23604, corynebacterium glutamicum CICC21269, corynebacterium glutamicum CICC21764, saccharomyces cerevisiae CICC32203 and plant lactobacillus plantarum CICC21809. The invention further discloses a preparation method of the compound bacterium liquid. According to the fermentation type low-protein daily ration for pigs and the production process thereof, the growth performance of fattening pigs can be improved, the feeding environment of a pig farm is improved, the health of livestock is improved, the feed cost is reduced, the protein digestibility in the daily ration can be effectively improved through biological fermentation, the amino acid balance is improved, and the nitrogen excretion amount is reduced; the low-protein daily ration has a wide application prospect in pig raising production, and the breeding benefit can be effectively improved through a reasonable design formula.

Description

Technical Field

[0001] The present invention relates to the technical field of microbial fermentation feed, and particularly relates to a fermented low-protein diet for pigs and its production process. Background Art

[0002] The so-called low-protein diet refers to reducing the crude protein level of the diet by 2 - 4 percentage points according to the nutritional requirements, while meeting the requirements of the types, proportions, and amounts of amino acids in the livestock and poultry diet, with the production performance of livestock and poultry remaining unchanged, and the feed conversion rate, nitrogen deposition in livestock and poultry, nitrogen emission, and heat stress resistance all being improved. Such a diet is a low-protein diet. A large number of research experiments at home and abroad have shown that for every 1 percentage point reduction in the dietary protein level, 10% - 15% of nitrogen excretion can be reduced. A successful low-protein diet can improve protein utilization rate and animal health, while appropriately reducing feed costs and ammonia nitrogen emissions, which is the green development path of the feed industry;

[0003] At the same time, the low-protein diets in the prior art have unbalanced amino acids and a relatively high risk of intestinal health problems for pigs after consumption. In the common low-protein diets on the market, the amount of soybean meal used is relatively low, but it is prone to amino acid imbalance and intestinal stress. However, the prior art solves this problem by adding free amino acids, but there are problems such as high cost and damage to the intestinal flora.

[0004] Therefore, it is very necessary to propose a fermented low-protein diet for pigs and its production process to solve the above problems. Summary of the Invention

[0005] The main purpose of the present invention is to provide a fermented low-protein diet for pigs and its production process, which can effectively solve the problems in the background art.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A fermented low-protein diet for pigs includes a compound bacterial liquid, corn, soybean meal, wheat middlings, sodium chloride, limestone powder, cane molasses, calcium hydrogen phosphate, choline chloride, and a premix. The compound bacterial liquid includes Corynebacterium glutamicum CICC23604, Corynebacterium glutamicum CICC21269, Corynebacterium glutamicum CICC21764, Saccharomyces cerevisiae CICC32203, and Lactobacillus plantarum CICC21809;

[0008] By mass, it includes: 400 - 600 parts of corn, 100 - 200 parts of soybean meal, 40 - 60 parts of wheat middlings, 15 - 25 parts of cane molasses, 2 - 5 parts of sodium chloride, 10 - 30 parts of limestone powder, 3 - 6 parts of calcium hydrogen phosphate, 1 - 2 parts of choline chloride, 4 - 6 parts of premix, and 200 - 300 parts of compound bacterial liquid;

[0009] In the said compound bacterial liquid, by mass parts, it includes: 20 - 30 parts of Corynebacterium glutamicum CICC23604, 20 - 30 parts of Corynebacterium glutamicum CICC21269, 20 - 30 parts of Corynebacterium glutamicum CICC21764, 30 - 20 parts of Saccharomyces cerevisiae CICC3220, and 10 - 20 parts of Lactobacillus plantarum CICC21809.

[0010] Preferably, the Corynebacterium glutamicum CICC23604 is preserved in the China Center for Industrial Culture Collection and is used for lysine production; the Corynebacterium glutamicum CICC21269 is preserved in the China Center for Industrial Culture Collection and is used for threonine production; the Corynebacterium glutamicum CICC21764 is preserved in the China Center for Industrial Culture Collection and is used for valine production; the Saccharomyces cerevisiae CICC32203 is preserved in the China Center for Industrial Culture Collection and is used for tryptophan production; the Lactobacillus plantarum CICC21809 is preserved in the China Center for Industrial Culture Collection and is used for lactic acid production to improve the growth performance and intestinal flora of piglets;

[0011] The Corynebacterium glutamicum is used to optimize the amino acid balance of the fermented low - protein pig diet by secreting essential amino acids; the Saccharomyces cerevisiae is used to provide tryptophan and promote nutrient absorption; the Lactobacillus plantarum inhibits harmful bacteria by producing lactic acid and improves the intestinal environment; the sugar in the cane molasses is used to promote microbial metabolism and increase amino acid production; the choline chloride is used to promote amino acid recycling and reduce feed costs; the amino acids secreted by the Corynebacterium glutamicum are used to provide a nitrogen source for the Saccharomyces cerevisiae to promote its tryptophan production; the lactic acid produced by the Lactobacillus plantarum is used to lower the pH value, inhibit Escherichia coli, and at the same time create a suitable environment for the Corynebacterium glutamicum.

[0012] Preferably, in the said fermented low - protein pig diet, the lysine content is 1.12% - 1.28%, the methionine content is 0.35% - 0.37%, the threonine content is 0.76% - 0.91%, the tryptophan content is 0.2% - 0.24%, the isoleucine content is 0.53% - 0.55%, the valine content is 0.87% - 1.04%, the crude protein content is 13.38% - 13.55%, the total acid content, calculated as lactic acid, is 1.92% - 2.43%, and the total number of functional viable bacteria is 2.7×10 8 - 3.5×10 8 CFU / g.

[0013] Preferably, the premix is prepared by blending vitamin A, vitamin D3, vitamin E, vitamin K3, vitamin B1, vitamin B2, vitamin B6, vitamin B12, nicotinamide, calcium pantothenate, folic acid, biotin, ferrous sulfate, copper sulfate, zinc sulfate, manganese sulfate, calcium iodate, and sodium selenite.

[0014] A preparation method of a fermented low-protein pig diet includes the following operating steps:

[0015] S1: Prepare the bacterial solutions of Corynebacterium glutamicum CICC23604, Corynebacterium glutamicum CICC21269, Corynebacterium glutamicum CICC21764, Saccharomyces cerevisiae CICC32203, and Lactobacillus plantarum CICC21809 respectively;

[0016] S101: The bacterial solution of Corynebacterium glutamicum CICC23604 is prepared as follows:

[0017] Preparation of liquid seed medium: Add 25 - 35 g of peptone, 4 - 6 g of beef extract powder, 1 - 2 g of glucose, and 4 - 6 g of NaCl into 1000 mL of distilled water, stir until completely dissolved, adjust the pH to 7.0 ± 0.2, and sterilize at a temperature of 115 - 121 °C for 15 - 20 min;

[0018] Preparation of liquid fermentation medium: Add 25 - 35 kg of peptone, 4 - 6 kg of beef extract powder, 1 - 2 kg of glucose, and 4 - 6 kg of NaCl into 1000 L of pure water, stir until completely dissolved, adjust the pH to 7.0 ± 0.2, and sterilize at a temperature of 115 - 121 °C for 15 - 20 min;

[0019] Cultivation conditions:

[0020] Including seed liquid culture: Inoculate the slant strain of Corynebacterium glutamicum CICC23604 into the liquid seed medium at a ratio of 1 loop / 50 - 100 ml, culture at a temperature of 28 - 32 °C, a rotation speed of 150 - 200 r / min, and oscillate for 18 - 30 h;

[0021] It also includes fermentation broth culture: Inoculate the above seed liquid into a fermenter containing the liquid fermentation medium at a volume ratio of 5% - 15%, at a temperature of 28 - 32 °C, introduce sterile air, the aeration ratio is 0.5 - 1.5 (m 3 / m 3 ·min), the tank pressure is 0.01 - 0.05 MPa, the rotation speed is 150 - 200 r / min, and culture for 18 - 30 h to obtain the bacterial solution of Corynebacterium glutamicum CICC23604;

[0022] S102: The bacterial solution of Corynebacterium glutamicum CICC21269 is prepared as follows:

[0023] Preparation of liquid seed culture medium: Add 4 - 6 g of peptone, 2 - 4 g of beef extract powder, and 4 - 6 g of NaCl into 1000 mL of distilled water, stir until completely dissolved, adjust the pH to 7.0 ± 0.2, and sterilize at 115 - 121 °C for 15 - 20 min;

[0024] Preparation of liquid fermentation culture medium: Add 4 - 6 kg of peptone, 2 - 4 kg of beef extract powder, and 4 - 6 kg of NaCl into 1000 L of pure water, stir until completely dissolved, adjust the pH to 7.0 ± 0.2, and sterilize at 115 - 121 °C for 15 - 20 min;

[0025] Cultivation conditions:

[0026] Culture of seed liquid: Inoculate the slant strain of Corynebacterium glutamicum CICC21269 into the liquid seed culture medium at a ratio of 1 loop / 50 - 100 ml, culture at 28 - 32 °C, rotation speed of 150 - 200 r / min, and shake culture for 18 - 30 h;

[0027] Culture of fermentation broth: Inoculate the above - mentioned seed liquid into the fermenter containing the liquid fermentation culture medium at a volume ratio of 5% - 15%, culture at 28 - 32 °C, introduce sterile air, aeration ratio is 0.5 - 1.5 (m 3 / m 3 ·min), tank pressure is 0.01 - 0.05 MPa, rotation speed is 150 - 200 r / min, and culture for 18 - 30 h to obtain the Corynebacterium glutamicum CICC21269 bacterial liquid;

[0028] S103: The preparation method of the Corynebacterium glutamicum CICC21764 bacterial liquid is the same as that of the Corynebacterium glutamicum CICC21269 bacterial liquid;

[0029] S104: The Saccharomyces cerevisiae CICC32203 bacterial liquid is prepared as follows:

[0030] Preparation of liquid seed culture medium: Add 25 - 35 g of malt extract powder and 2 - 5 g of soy peptone into 1000 mL of distilled water, stir until completely dissolved, adjust the pH to 5.6 ± 0.2, and sterilize at 115 - 121 °C for 15 - 20 min;

[0031] Preparation of liquid fermentation culture medium: Add 15 - 25 kg of peptone, 5 - 15 kg of yeast extract, and 15 - 25 kg of glucose into 1000 L of pure water, stir until completely dissolved, adjust the pH to 5.6 ± 0.2, and sterilize at 115 - 121 °C for 15 - 20 min;

[0032] Cultivation conditions:

[0033] Seed culture: Inoculate the slant culture of Saccharomyces cerevisiae CICC32203 into the liquid seed medium at a ratio of 1 loop / 50 - 100 ml, culture with shaking at a temperature of 25 - 30 °C, a rotation speed of 150 - 200 r / min for 18 - 30 h;

[0034] Fermentation broth culture: Inoculate the above seed liquid into the fermenter containing the liquid fermentation medium at a volume ratio of 5% - 15%, culture at a temperature of 25 - 30 °C, introduce sterile air, the aeration ratio is 0.5 - 1.5 (m 3 / m 3 ·min), the tank pressure is 0.01 - 0.05 MPa, the rotation speed is 150 - 200 r / min, culture for 18 - 30 h to obtain the Saccharomyces cerevisiae CICC32203 bacterial liquid;

[0035] S105: The bacterial liquid of Lactiplantibacillus plantarum CICC21809 is prepared as follows:

[0036] Preparation of liquid seed medium: Add 8 - 12 g of peptone, 8 - 12 g of beef extract, 3 - 7 g of yeast extract powder, 15 - 25 g of glucose, 3 - 7 g of sodium acetate, 1 - 2 g of trisodium citrate, 1 - 2 g of Tween 80, 1 - 3 g of K 2 HPO 4 , 0.1 - 0.3 g of MgSO 4 .7H 2 O, 0.03 - 0.07 g of MnSO 4 .H 2 O into 1000 mL of distilled water, stir until completely dissolved, adjust the pH to 6.5 ± 0.2, and sterilize at a temperature of 115 - 121 °C for 15 - 20 min;

[0037] Preparation of liquid fermentation medium: Add 8 - 12 kg of peptone, 8 - 12 kg of beef extract, 3 - 7 kg of yeast extract powder, 15 - 25 kg of glucose, 3 - 7 kg of sodium acetate, 1 - 2 kg of trisodium citrate, 1 - 2 kg of Tween 80, 1 - 3 kg of K 2 HPO 4 , 0.1 - 0.3 kg of MgSO 4 .7H 2 O, 0.03 - 0.07 kg of MnSO 4 H 2 O into 1000 L of pure water, stir until completely dissolved, adjust the pH to 6.5 ± 0.2, and sterilize at a temperature of 115 - 121 °C for 15 - 20 min;

[0038] Cultivation conditions:

[0039] Seed culture: Inoculate the slant culture of Lactobacillus plantarum CICC21809 into the liquid seed medium at a ratio of 1 loop per 50 - 100 ml, and culture it at a temperature of 32 - 37°C, a rotation speed of 100 - 150 r / min with shaking for 18 - 30 h;

[0040] Fermentation broth culture: Inoculate the above seed liquid into a fermenter containing liquid fermentation medium at a volume ratio of 5% - 15%, and culture it at a temperature of 32 - 37°C, while introducing sterile air, with an aeration ratio of 0.5 - 1.5 (m 3 / m 3 ·min), a tank pressure of 0.01 - 0.05 MPa, a rotation speed of 100 - 150 r / min for 18 - 30 h to obtain the Lactobacillus plantarum bacterial liquid;

[0041] S2: Weigh and compound. Compound the prepared Corynebacterium glutamicum CICC23604 bacterial liquid, Corynebacterium glutamicum CICC21269 bacterial liquid, Corynebacterium glutamicum CICC21764 bacterial liquid, Saccharomyces cerevisiae CICC32203 bacterial liquid and Lactobacillus plantarum CICC21809 bacterial liquid by volume fraction. Among them, 20 - 30 parts of Corynebacterium glutamicum CICC23604 bacterial liquid, 20 - 30 parts of Corynebacterium glutamicum CICC21269 bacterial liquid, 20 - 30 parts of Corynebacterium glutamicum CICC21764 bacterial liquid, 10 - 20 parts of Saccharomyces cerevisiae CICC32203 bacterial liquid, and 10 - 20 parts of Lactobacillus plantarum CICC21809 bacterial liquid. Based on this, a compound bacterial liquid is prepared;

[0042] S3: Preparation of solid - state fermentation carrier. Thoroughly mix 400 - 600 parts of corn, 100 - 200 parts of soybean meal, 40 - 60 parts of wheat middlings, 2 - 5 parts of sodium chloride, 10 - 30 parts of limestone powder, 15 - 25 parts of cane molasses, 3 - 6 parts of calcium hydrogen phosphate, 1 - 2 parts of choline chloride and 4 - 6 parts of premix to prepare the solid - state fermentation carrier;

[0043] S4: Mixing treatment. Spray the compound bacterial liquid evenly into the solid - state fermentation carrier according to a mass ratio of 1:3 - 1:4, mix thoroughly, place it in a solid - state fermentation device and ferment it under aerobic and constant temperature conditions of 30 - 32°C for 5 d - 7 d. After fermentation, pack it to prepare a fermented low - protein pig diet. The fermented low - protein pig diet can increase the average daily gain of growing - finishing pigs by 9% - 12%; increase the nitrogen utilization rate by 15% - 20%; reduce the diarrhea rate by 70% - 80%; reduce the nitrogen excretion amount by 30% - 40%, reduce the serum urea nitrogen concentration by 20% - 40%; reduce the number of Escherichia coli in pig manure by 25% - 35% and increase the number of lactic acid bacteria in pig manure by 25% - 35%;

[0044] Among them, solid-state fermentation is divided into two stages: the first stage is from 0 to 3 days, with the temperature controlled at 30°C and the humidity at 60%, which is used to promote amino acid secretion; the second stage is from 4 to 7 days, with the temperature raised to 32°C and the humidity reduced to 50%, which is used to promote the proliferation of lactic acid bacteria.

[0045] Compared with the prior art, the present invention provides a fermented low-protein pig diet and its production process, which have the following beneficial effects:

[0046] 1. The fermented low-protein pig diet and its production process can increase the average daily gain of growing and finishing pigs by 9%-12%; increase the nitrogen utilization rate by 15%-20%; reduce the diarrhea rate by 70%-80%; reduce the nitrogen excretion amount by 30%-40%, and reduce the serum urea nitrogen concentration by 20%-40%; reduce the number of Escherichia coli in pig manure by 25%-35%, and increase the number of lactic acid bacteria in pig manure by 25%-35%.

[0047] 2. The fermented low-protein pig diet and its production process, in which the crude protein (CP13%) of the product is about 3% lower than that of the conventional finishing pig (body weight 30kg±2kg) compound feed (CP16%), the soybean meal usage is reduced by 20%-30%, the feed cost is reduced by 10%-15%, and the cost per kilogram of weight gain is reduced by about 10%-15%.

[0048] 3. The fermented low-protein pig diet and its production process contain active probiotics that can regulate the balance of intestinal microflora, produce intestinal immune responses, improve digestive functions, reduce the production of potential toxic metabolites in the hindgut, such as ammonia and amines, and prevent digestive tract diseases. Description of the Drawings

[0049] Figure 1 is the preparation flow chart of the present invention. Detailed Embodiments

[0050] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

[0051] A fermented low-protein pig diet includes a compound bacterial solution, corn, soybean meal, wheat middlings, sodium chloride, stone powder, cane molasses, calcium hydrogen phosphate, choline chloride, and a premix. The compound bacterial solution includes Corynebacterium glutamicum CICC23604, Corynebacterium glutamicum CICC21269, Corynebacterium glutamicum CICC21764, Saccharomyces cerevisiae CICC32203, and Lactiplantibacillus plantarum CICC21809;

[0052] By mass parts, it includes: 400 - 600 parts of corn, 100 - 200 parts of soybean meal, 40 - 60 parts of wheat middlings, 15 - 25 parts of cane molasses, 2 - 5 parts of sodium chloride, 10 - 30 parts of limestone powder, 3 - 6 parts of calcium hydrogen phosphate, 1 - 2 parts of choline chloride, 4 - 6 parts of premix, 200 - 300 parts of compound bacterial liquid;

[0053] In the compound bacterial liquid, by mass parts, it includes: 20 - 30 parts of Corynebacterium glutamicum CICC23604, 20 - 30 parts of Corynebacterium glutamicum CICC21269, 20 - 30 parts of Corynebacterium glutamicum CICC21764, 30 - 20 parts of Saccharomyces cerevisiae CICC3220, 10 - 20 parts of Lactobacillus plantarum CICC21809.

[0054] Corynebacterium glutamicum CICC23604 is deposited in the China Center for Industrial Culture Collection and is used for producing lysine; Corynebacterium glutamicum CICC21269 is deposited in the China Center for Industrial Culture Collection and is used for producing threonine; Corynebacterium glutamicum CICC21764 is deposited in the China Center for Industrial Culture Collection and is used for producing valine; Saccharomyces cerevisiae CICC32203 is deposited in the China Center for Industrial Culture Collection and is used for producing tryptophan; Lactobacillus plantarum CICC21809 is deposited in the China Center for Industrial Culture Collection and is used for producing lactic acid to improve the growth performance and intestinal flora of piglets;

[0055] The said Corynebacterium glutamicum is used to optimize the amino acid balance of the fermented low - protein diet for pigs by secreting essential amino acids; the Saccharomyces cerevisiae is used to provide tryptophan and promote nutrient absorption; the Lactobacillus plantarum inhibits harmful bacteria by producing lactic acid and improves the intestinal environment; the sugar in the cane molasses is used to promote microbial metabolism and increase the amino acid yield; the choline chloride is used to promote amino acid recycling and reduce feed costs. The amino acids secreted by Corynebacterium glutamicum are used to provide a nitrogen source for Saccharomyces cerevisiae to promote its production of tryptophan; the lactic acid produced by Lactobacillus plantarum is used to lower the pH value, inhibit Escherichia coli, and at the same time create a suitable environment for Corynebacterium glutamicum.

[0056] In the fermented low - protein diet for pigs, the lysine content is 1.12% - 1.28%, the methionine content is 0.35% - 0.37%, the threonine content is 0.76% - 0.91%, the tryptophan content is 0.2% - 0.24%, the isoleucine content is 0.53% - 0.55%, the valine content is 0.87% - 1.04%, the crude protein content is 13.38% - 13.55%, the total acid content, calculated as lactic acid, is 1.92% - 2.43%, and the total number of functional viable bacteria is 2.7×10 8 - 3.5×10 8 CFU / g.

[0057] The premix is prepared by mixing vitamin A, vitamin D3, vitamin E, vitamin K3, vitamin B1, vitamin B2, vitamin B6, vitamin B12, nicotinamide, calcium pantothenate, folic acid, biotin, ferrous sulfate, copper sulfate, zinc sulfate, manganese sulfate, calcium iodate, and sodium selenite together.

[0058] As Figure 1 shown, a preparation method of a fermented low-protein pig diet includes the following operating steps:

[0059] S1: Prepare the bacterial solutions of Corynebacterium glutamicum CICC23604, Corynebacterium glutamicum CICC21269, Corynebacterium glutamicum CICC21764, Saccharomyces cerevisiae CICC32203, and Lactiplantibacillus plantarum CICC21809 respectively;

[0060] S101: The bacterial solution of Corynebacterium glutamicum CICC23604 is prepared as follows:

[0061] Preparation of liquid seed medium: Add 25 - 35 g of peptone, 4 - 6 g of beef extract powder, 1 - 2 g of glucose, and 4 - 6 g of NaCl into 1000 mL of distilled water, stir until completely dissolved, adjust the pH to 7.0 ± 0.2, and sterilize at a temperature of 115 - 121 °C for 15 - 20 min;

[0062] Preparation of liquid fermentation medium: Add 25 - 35 kg of peptone, 4 - 6 kg of beef extract powder, 1 - 2 kg of glucose, and 4 - 6 kg of NaCl into 1000 L of pure water, stir until completely dissolved, adjust the pH to 7.0 ± 0.2, and sterilize at a temperature of 115 - 121 °C for 15 - 20 min;

[0063] Cultivation conditions:

[0064] Including seed liquid cultivation: Inoculate the slant strain of Corynebacterium glutamicum CICC23604 into the liquid seed medium at a ratio of 1 loop / 50 - 100 ml, cultivate at a temperature of 28 - 32 °C, a rotation speed of 150 - 200 r / min, and oscillate for 18 - 30 h;

[0065] It also includes fermentation broth cultivation: Inoculate the above seed liquid into the fermenter containing the liquid fermentation medium at a volume ratio of 5% - 15%, at a temperature of 28 - 32 °C, introduce sterile air, the aeration ratio is 0.5 - 1.5 (m 3 / m 3 ·min), the tank pressure is 0.01 - 0.05 MPa, the rotation speed is 150 - 200 r / min, and cultivate for 18 - 30 h to obtain the bacterial solution of Corynebacterium glutamicum CICC23604;

[0066] S102: The Corynebacterium glutamicum CICC21269 bacterial solution is prepared as follows:

[0067] Preparation of liquid seed medium: Add 4 - 6 g of peptone, 2 - 4 g of beef extract powder, and 4 - 6 g of NaCl into 1000 mL of distilled water, stir until completely dissolved, adjust the pH to 7.0 ± 0.2, and sterilize at a temperature of 115 - 121 °C for 15 - 20 min;

[0068] Preparation of liquid fermentation medium: Add 4 - 6 kg of peptone, 2 - 4 kg of beef extract powder, and 4 - 6 kg of NaCl into 1000 L of pure water, stir until completely dissolved, adjust the pH to 7.0 ± 0.2, and sterilize at a temperature of 115 - 121 °C for 15 - 20 min;

[0069] Cultivation conditions:

[0070] Cultivation of seed liquid: Inoculate the slant culture of Corynebacterium glutamicum CICC21269 into the liquid seed medium at a ratio of 1 loop / 50 - 100 ml, cultivate at a temperature of 28 - 32 °C, a rotation speed of 150 - 200 r / min, and shake culture for 18 - 30 h;

[0071] Cultivation of fermentation broth: Inoculate the above - mentioned seed liquid into a fermenter containing liquid fermentation medium at a volume ratio of 5% - 15%, at a temperature of 28 - 32 °C, introduce sterile air, the aeration ratio is 0.5 - 1.5 (m 3 / m 3 ·min), the tank pressure is 0.01 - 0.05 MPa, the rotation speed is 150 - 200 r / min, and cultivate for 18 - 30 h to obtain the Corynebacterium glutamicum CICC21269 bacterial solution;

[0072] S103: The preparation method of the Corynebacterium glutamicum CICC21764 bacterial solution is the same as that of the Corynebacterium glutamicum CICC21269 bacterial solution;

[0073] S104: The Saccharomyces cerevisiae CICC32203 bacterial solution is prepared as follows:

[0074] Preparation of liquid seed medium: Add 25 - 35 g of malt extract powder and 2 - 5 g of soy peptone into 1000 mL of distilled water, stir until completely dissolved, adjust the pH to 5.6 ± 0.2, and sterilize at a temperature of 115 - 121 °C for 15 - 20 min;

[0075] Preparation of liquid fermentation medium: Add 15 - 25 kg of peptone, 5 - 15 kg of yeast extract, and 15 - 25 kg of glucose into 1000 L of pure water, stir until completely dissolved, adjust the pH to 5.6 ± 0.2, and sterilize at a temperature of 115 - 121 °C for 15 - 20 min;

[0076] Cultivation conditions:

[0077] Seed culture: Inoculate the slant strain of Saccharomyces cerevisiae CICC32203 into the liquid seed medium at a ratio of 1 loop / 50 - 100 ml, culture at a temperature of 25 - 30 °C, a rotation speed of 150 - 200 r / min, and shake culture for 18 - 30 h;

[0078] Fermentation broth culture: Inoculate the above-mentioned seed liquid into the fermenter containing the liquid fermentation medium at a volume ratio of 5% - 15%, culture at a temperature of 25 - 30 °C, introduce sterile air, the aeration ratio is 0.5 - 1.5 (m 3 / m3·min), the tank pressure is 0.01 - 0.05 MPa, the rotation speed is 150 - 200 r / min, and culture for 18 - 30 h to obtain the bacterial liquid of Saccharomyces cerevisiae CICC32203;

[0079] S105: The bacterial liquid of Lactiplantibacillus plantarum CICC21809 is prepared as follows:

[0080] Preparation of liquid seed medium: Add 8 - 12 g of peptone, 8 - 12 g of beef extract, 3 - 7 g of yeast extract powder, 15 - 25 g of glucose, 3 - 7 g of sodium acetate, 1 - 2 g of trisodium citrate, 1 - 2 g of Tween 80, 1 - 3 g of K 2 HPO 4 , 0.1 - 0.3 g of MgSO 4 .7H 2 O, 0.03 - 0.07 g of MnSO 4 .H 2 O into 1000 mL of distilled water, stir until completely dissolved, adjust the pH to 6.5 ± 0.2, and sterilize at a temperature of 115 - 121 °C for 15 - 20 min;

[0081] Preparation of liquid fermentation medium: Add 8 - 12 kg of peptone, 8 - 12 kg of beef extract, 3 - 7 kg of yeast extract powder, 15 - 25 kg of glucose, 3 - 7 kg of sodium acetate, 1 - 2 kg of trisodium citrate, 1 - 2 kg of Tween 80, 1 - 3 kg of K 2 HPO 4 , 0.1 - 0.3 kg of MgSO 4 .7H 2 O, 0.03 - 0.07 kg of MnSO 4 H 2 O into 1000 L of pure water, stir until completely dissolved, adjust the pH to 6.5 ± 0.2, and sterilize at a temperature of 115 - 121 °C for 15 - 20 min;

[0082] Cultivation conditions:

[0083] Seed culture: Inoculate the slant culture of Lactobacillus plantarum CICC21809 into the liquid seed medium at a ratio of 1 loop per 50 - 100 ml, and culture it at a temperature of 32 - 37°C, a rotation speed of 100 - 150 r / min, with shaking for 18 - 30 h;

[0084] Fermentation broth culture: Inoculate the above-mentioned seed liquid into a fermenter containing liquid fermentation medium at a volume ratio of 5% - 15%, at a temperature of 32 - 37°C, introduce sterile air, with an aeration ratio of 0.5 - 1.5 (m 3 / m 3 ·min), a tank pressure of 0.01 - 0.05 MPa, a rotation speed of 100 - 150 r / min, and culture for 18 - 30 h to obtain the Lactobacillus plantarum bacterial liquid;

[0085] S2: Weigh and compound. Compound the obtained Corynebacterium glutamicum CICC23604 bacterial liquid, Corynebacterium glutamicum CICC21269 bacterial liquid, Corynebacterium glutamicum CICC21764 bacterial liquid, Saccharomyces cerevisiae CICC32203 bacterial liquid, and Lactobacillus plantarum CICC21809 bacterial liquid by volume fraction. Among them, the Corynebacterium glutamicum CICC23604 bacterial liquid is 20 - 30 parts, the Corynebacterium glutamicum CICC21269 bacterial liquid is 20 - 30 parts, the Corynebacterium glutamicum CICC21764 bacterial liquid is 20 - 30 parts, the Saccharomyces cerevisiae CICC32203 bacterial liquid is 10 - 20 parts, and the Lactobacillus plantarum CICC21809 bacterial liquid is 10 - 20 parts. Based on this, a compound bacterial liquid is prepared;

[0086] S3: Preparation of solid fermentation carrier. Thoroughly mix 400 - 600 parts of corn, 100 - 200 parts of soybean meal, 40 - 60 parts of wheat middlings, 2 - 5 parts of sodium chloride, 10 - 30 parts of stone powder, 15 - 25 parts of cane molasses, 3 - 6 parts of calcium hydrogen phosphate, 1 - 2 parts of choline chloride, and 4 - 6 parts of premix to prepare the solid fermentation carrier;

[0087] S4: Mixing treatment. Spray the compound bacterial liquid evenly into the solid fermentation carrier according to a mass ratio of 1:3 - 1:4, mix thoroughly, place it in a solid fermentation device, and ferment it under aerobic and constant temperature conditions of 30 - 32°C for 5 d - 7 d. After fermentation, pack it to prepare a fermented low - protein pig diet. The fermented low - protein pig diet can increase the average daily gain of growing - finishing pigs by 9% - 12%; increase the nitrogen utilization rate by 15% - 20%; reduce the diarrhea rate by 70% - 80%; reduce the nitrogen excretion amount by 30% - 40%, reduce the serum urea nitrogen concentration by 20% - 40%; reduce the number of Escherichia coli in pig manure by 25% - 35%, and increase the number of lactic acid bacteria in pig manure by 25% - 35%;

[0088] Among them, solid-state fermentation is divided into two stages: the first stage is from 0 to 3 days, controlling the temperature at 30°C and the humidity at 60% to promote amino acid secretion; the second stage is from 4 to 7 days, raising the temperature to 32°C and reducing the humidity to 50% to promote the proliferation of lactic acid bacteria.

[0089] Example 1:

[0090] As Figure 1 shown, a preparation method of a fermented low-protein pig diet includes the following steps:

[0091] S1: Prepare Corynebacterium glutamicum CICC23604 bacterial liquid, Corynebacterium glutamicum CICC21269 bacterial liquid, Corynebacterium glutamicum CICC21764 bacterial liquid, Saccharomyces cerevisiae CICC32203 bacterial liquid, and Lactiplantibacillus plantarum CICC21809 bacterial liquid respectively.

[0092] S101: The Corynebacterium glutamicum CICC23604 bacterial liquid is prepared as follows:

[0093] Preparation of liquid seed medium: Add 25 g of peptone, 4 g of beef extract powder, 1 g of glucose, and 4 g of NaCl to 1000 mL of distilled water, stir until completely dissolved, adjust the pH to 7.2, and sterilize at 121°C for 15 min;

[0094] Preparation of liquid fermentation medium: Add 25 kg of peptone, 4 kg of beef extract powder, 1 kg of glucose, and 4 kg of NaCl to 1000 L of pure water, stir until completely dissolved, adjust the pH to 7.2, and sterilize at 121°C for 20 min;

[0095] Cultivation conditions:

[0096] Seed liquid culture: Inoculate the Corynebacterium glutamicum slant strain into the liquid seed medium at a ratio of 1 loop / 50 ml, at a temperature of 30°C, a rotation speed of 180 r / min, and shake culture for 24 h;

[0097] Fermentation broth culture: Inoculate the above seed liquid into a fermenter containing liquid fermentation medium at a volume ratio of 5%, at a temperature of 30°C, introduce sterile air, the aeration ratio is 1.0 (m 3 / m 3 ·min), the tank pressure is 0.03 MPa, the rotation speed is 150 r / min, and culture for 24 h to obtain Corynebacterium glutamicum bacterial liquid.

[0098] S102: The Corynebacterium glutamicum CICC21269 bacterial liquid and the Corynebacterium glutamicum CICC21764 bacterial liquid are prepared as follows:

[0099] Preparation of liquid seed medium: Add 4 g of peptone, 2 g of beef extract powder, and 4 g of NaCl to 1000 mL of distilled water, stir until completely dissolved, adjust the pH to 7.0, and sterilize at 121 °C for 15 min;

[0100] Preparation of liquid fermentation medium: Add 4 kg of peptone, 2 kg of beef extract powder, and 4 kg of NaCl to 1000 L of pure water, stir until completely dissolved, adjust the pH to 7.0, and sterilize at 121 °C for 20 min;

[0101] Cultivation conditions:

[0102] Cultivation of seed liquid: Inoculate the slant culture of Corynebacterium glutamicum into the liquid seed medium at a ratio of 1 loop / 50 ml, cultivate at 30 °C, a rotation speed of 180 r / min, and shake culture for 24 h;

[0103] Cultivation of fermentation broth: Inoculate the above seed liquid into the fermenter containing the liquid fermentation medium at a volume ratio of 5%, cultivate at 30 °C, introduce sterile air, the aeration ratio is 1.0 (m 3 / m 3 ·min), the tank pressure is 0.03 MPa, the rotation speed is 150 r / min, and cultivate for 24 h to obtain the bacterial solutions of Corynebacterium glutamicum CICC21269 and Corynebacterium glutamicum CICC21764.

[0104] S103: The bacterial solution of Saccharomyces cerevisiae CICC32203 is prepared as follows:

[0105] Preparation of liquid seed medium: Add 25 g of malt extract powder and 2 g of soy peptone to 1000 mL of distilled water, stir until completely dissolved, adjust the pH to 5.6, and sterilize at 115 °C for 15 min;

[0106] Preparation of liquid fermentation medium: Add 15 kg of peptone, 5 kg of yeast extract, and 15 kg of glucose to 1000 L of pure water, stir until completely dissolved, adjust the pH to 5.6, and sterilize at 121 °C for 20 min;

[0107] Cultivation conditions:

[0108] Cultivation of seed liquid: Inoculate the slant culture of Saccharomyces cerevisiae into the liquid seed medium at a ratio of 1 loop / 50 ml, cultivate at 30 °C, a rotation speed of 180 r / min, and shake culture for 24 h;

[0109] Cultivation of fermentation broth: Inoculate the above seed liquid into the fermenter containing the liquid fermentation medium at a volume ratio of 5%, cultivate at 30 °C, introduce sterile air, the aeration ratio is 1.0 (m 3 / m 3· min), tank pressure 0.03 MPa, rotation speed 150 r / min, culture for 24 h to obtain Saccharomyces cerevisiae liquid.

[0110] S104: The Lactiplantibacillus plantarum CICC21809 bacterial liquid was prepared as follows:

[0111] Preparation of liquid seed medium: Add 8 g of peptone, 8 g of beef extract, 3 g of yeast extract powder, 15 g of glucose, 3 g of sodium acetate, 1 g of ammonium citrate, 1 g of Tween 80, 1 g of K 2 HPO 4 , 0.1 g of MgSO 4 .7H 2 O, 0.03 g of MnSO 4 .H 2 O to 1000 mL of distilled water, stir until completely dissolved, adjust the pH to 6.5, and sterilize at 121 °C for 15 min;

[0112] Preparation of liquid fermentation medium: Add 8 kg of peptone, 8 kg of beef extract, 3 kg of yeast extract powder, 15 kg of glucose, 3 kg of sodium acetate, 1 kg of ammonium citrate, 1 kg of Tween 80, 1 kg of K 2 HPO 4 , 0.1 kg of MgSO 4 .7H 2 O, 0.03 kg of MnSO 4 H 2 O to 1000 L of pure water, stir until completely dissolved, adjust the pH to 6.5, and sterilize at 121 °C for 20 min;

[0113] Cultivation conditions:

[0114] Cultivation of seed liquid: Inoculate the Lactiplantibacillus plantarum slant strain into the liquid seed medium at a ratio of 1 loop / 50 ml, culture at 37 °C, rotation speed 120 r / min, and shake culture for 24 h;

[0115] Cultivation of fermentation broth: Inoculate the above seed liquid into the fermenter containing the liquid fermentation medium at a volume ratio of 5%, culture at 37 °C, introduce sterile air, and the aeration ratio is 0.5 (m 3 / m 3 · min), tank pressure 0.03 MPa, rotation speed 120 r / min, culture for 24 h to obtain Lactiplantibacillus plantarum bacterial liquid.

[0116] S2: Weigh and compound the prepared Corynebacterium glutamicum CICC23604 bacterial liquid, Corynebacterium glutamicum CICC21269 bacterial liquid, Corynebacterium glutamicum CICC21764 bacterial liquid, Saccharomyces cerevisiae CICC32203 bacterial liquid, and Lactiplantibacillus plantarum CICC21809 bacterial liquid according to the following volume parts to prepare 200 kg of compound bacterial liquid:

[0117] 20 parts of Corynebacterium glutamicum CICC23604, 20 parts of Corynebacterium glutamicum CICC21269, 20 parts of Corynebacterium glutamicum CICC21764, 20 parts of Saccharomyces cerevisiae CICC32203, and 20 parts of Lactiplantibacillus plantarum CICC21809.

[0118] S3: Thoroughly mix 550 parts of corn, 150 parts of soybean meal, 40 parts of wheat middlings, 4 parts of sodium chloride, 20 parts of limestone powder, 25 parts of cane molasses, 5 parts of calcium hydrogen phosphate, 1 part of choline chloride, and 5 parts of premix to prepare a solid fermentation carrier.

[0119] S4: Spray the compound bacterial liquid evenly onto 800 kg of the solid fermentation carrier according to a mass ratio of 1:4, mix thoroughly, ferment aerobically and at a constant temperature of 30 °C for 7 days in a solid fermentation device, and pack after fermentation to prepare a fermented low-protein pig diet.

[0120] The technical indicators of the product prepared according to this example: crude protein 13.38%, lysine 1.12%, methionine 0.35%, threonine 0.76%, tryptophan 0.24%, isoleucine 0.53%, valine 0.87%, total acid content (calculated as lactic acid) 1.92%, total number of functional viable bacteria (CFU / g) 2.7×10 8 .

[0121] Example 2:

[0122] As Figure 1 shown, a preparation method of a fermented low-protein pig diet includes the following steps:

[0123] S1: Prepare Corynebacterium glutamicum CICC23604 bacterial liquid, Corynebacterium glutamicum CICC21269 bacterial liquid, Corynebacterium glutamicum CICC21764 bacterial liquid, Saccharomyces cerevisiae CICC32203 bacterial liquid, and Lactiplantibacillus plantarum CICC21809 bacterial liquid respectively.

[0124] S101: The Corynebacterium glutamicum CICC23604 bacterial liquid is prepared according to the following method:

[0125] Preparation of liquid seed medium: Add 30 g of peptone, 5 g of beef extract powder, 1 g of glucose, and 5 g of NaCl into 1000 mL of distilled water, stir until completely dissolved, adjust the pH to 7.2, and sterilize at 121 °C for 15 min;

[0126] Preparation of liquid fermentation medium: Add 30 kg of peptone, 5 kg of beef extract powder, 1 kg of glucose, and 5 kg of NaCl into 1000 L of pure water, stir until completely dissolved, adjust the pH to 7.2, and sterilize at 121 °C for 20 min;

[0127] Cultivation conditions:

[0128] Cultivation of seed liquid: Inoculate the slant culture of Corynebacterium glutamicum into the liquid seed medium at a ratio of 1 loop / 50 ml, culture at 30 °C, rotation speed of 180 r / min, and shake culture for 24 h;

[0129] Cultivation of fermentation broth: Inoculate the above seed liquid into the fermenter containing the liquid fermentation medium at a volume ratio of 10%, culture at 30 °C, introduce sterile air, aeration ratio is 1.2 (m 3 / m 3 ·min), tank pressure of 0.03 MPa, rotation speed of 150 r / min, and culture for 30 h to obtain the Corynebacterium glutamicum bacterial liquid.

[0130] S102: The bacterial liquids of Corynebacterium glutamicum CICC21269 and Corynebacterium glutamicum CICC21764 are prepared as follows:

[0131] Preparation of liquid seed medium: Add 5 g of peptone, 3 g of beef extract powder, and 5 g of NaCl into 1000 mL of distilled water, stir until completely dissolved, adjust the pH to 7.0, and sterilize at 121 °C for 15 min;

[0132] Preparation of liquid fermentation medium: Add 5 kg of peptone, 3 kg of beef extract powder, and 5 kg of NaCl into 1000 L of pure water, stir until completely dissolved, adjust the pH to 7.0, and sterilize at 121 °C for 20 min;

[0133] Cultivation conditions:

[0134] Cultivation of seed liquid: Inoculate the slant culture of Corynebacterium glutamicum into the liquid seed medium at a ratio of 1 loop / 50 ml, culture at 30 °C, rotation speed of 180 r / min, and shake culture for 24 h;

[0135] Cultivation of fermentation broth: Inoculate the above seed liquid into the fermenter containing the liquid fermentation medium at a volume ratio of 10%, culture at 30 °C, introduce sterile air, aeration ratio is 1.2 (m 3 / m 3· min), tank pressure 0.03 MPa, rotation speed 150 r / min, culture for 30 h to obtain Corynebacterium glutamicum CICC21269 bacterial liquid and Corynebacterium glutamicum CICC21764 bacterial liquid.

[0136] S103: The Saccharomyces cerevisiae CICC32203 bacterial liquid is prepared as follows:

[0137] Preparation of liquid seed medium: Add 30 g of malt extract powder and 3 g of soy peptone to 1000 mL of distilled water, stir until completely dissolved, adjust the pH to 5.6, and sterilize at 115 °C for 15 min;

[0138] Preparation of liquid fermentation medium: Add 20 kg of peptone, 10 kg of yeast extract, and 20 kg of glucose to 1000 L of pure water, stir until completely dissolved, adjust the pH to 5.6, and sterilize at 121 °C for 20 min;

[0139] C. Culture conditions:

[0140] Culture of seed liquid: Inoculate the Saccharomyces cerevisiae slant strain into the liquid seed medium at a ratio of 1 loop / 50 ml, culture at 30 °C, rotation speed 180 r / min, and shake culture for 24 h;

[0141] Culture of fermentation broth: Inoculate the above seed liquid into the fermenter containing the liquid fermentation medium at a volume ratio of 10%, culture at 30 °C, and introduce sterile air with an aeration ratio of 1.2 (m 3 / m 3 · min), tank pressure 0.03 MPa, rotation speed 150 r / min, culture for 30 h to obtain Saccharomyces cerevisiae bacterial liquid.

[0142] S104: The Lactiplantibacillus plantarum CICC21809 bacterial liquid is prepared as follows:

[0143] Preparation of seed medium: Add 10 g of casein peptone, 10 g of beef extract, 5 g of yeast extract powder, 20 g of glucose, 5 g of sodium acetate, 2 g of trisodium citrate, 1 g of Tween 80, 2 g of K 2 HPO 4 , 0.2 g of MgSO 4 .7H 2 O, 0.05 g of MnSO 4 .H 2 O to 1000 mL of distilled water, stir until completely dissolved, adjust the pH to 6.5, and sterilize at 121 °C for 15 min;

[0144] B. Preparation of liquid fermentation medium: Add 10 kg of peptone, 10 kg of beef extract, 5 kg of yeast extract powder, 20 kg of glucose, 3 kg of sodium acetate, 1 kg of ammonium citrate, 1 kg of Tween 80, 1 kg of K 2 HPO 4 、0.1 kg of MgSO 4 .7H 2 O, 0.03 kg of MnSO 4 H 2 O into 1000 L of pure water, stir until completely dissolved, adjust the pH to 6.5, and sterilize at 121 °C for 20 min;

[0145] Cultivation conditions:

[0146] Seed liquid culture: Inoculate the slant culture of Lactobacillus plantarum into the liquid seed medium at a ratio of 1 loop / 50 ml, culture at 37 °C, rotation speed of 120 r / min, and shake culture for 24 h;

[0147] Fermentation broth culture: Inoculate the above seed liquid into the fermenter containing the liquid fermentation medium at a volume ratio of 10%, culture at 37 °C, introduce sterile air, aeration ratio of 0.5 (m 3 / m 3 ·min), tank pressure of 0.03 MPa, rotation speed of 120 r / min, and culture for 30 h to obtain the fermentation broth of Lactobacillus plantarum.

[0148] S2: Weigh and mix the prepared Corynebacterium glutamicum CICC23604 bacterial liquid, Corynebacterium glutamicum CICC21269 bacterial liquid, Corynebacterium glutamicum CICC21764 bacterial liquid, Saccharomyces cerevisiae CICC32203 bacterial liquid, and Lactobacillus plantarum CICC21809 bacterial liquid according to the following volume parts to prepare 250 kg of compound bacterial liquid.

[0149] 25 parts of Corynebacterium glutamicum CICC23604, 25 parts of Corynebacterium glutamicum CICC21269, 15 parts of Corynebacterium glutamicum CICC21764, 15 parts of Saccharomyces cerevisiae CICC32203, 20 parts of Lactobacillus plantarum CICC21809.

[0150] S3: Thoroughly mix 500 parts of corn, 150 parts of soybean meal, 50 parts of wheat middlings, 4 parts of sodium chloride, 20 parts of stone powder, 15 parts of cane molasses, 5 parts of calcium hydrogen phosphate, 1 part of choline chloride, and 5 parts of premix to prepare 750 kg of solid fermentation carrier.

[0151] S4: Sprinkle the compound bacterial liquid evenly into the solid fermentation carrier according to a mass ratio of 1:3, mix thoroughly, ferment aerobically at a constant temperature of 30 °C for 7 d in a solid fermentation device, and pack after fermentation is completed to prepare a fermented low-protein pig diet.

[0152] S5: Technical indicators of the product prepared according to this example: crude protein 13.55%, lysine 1.28%, methionine 0.37%, threonine 0.91%, tryptophan 0.2%, isoleucine 0.55%, valine 1.04%, total acid content (calculated as lactic acid) 2.43%, total number of functional live bacteria (CFU / g) 3.5×10 8 。

[0153] Example 3:

[0154] An animal feeding experiment on a fermented low-protein pig diet:

[0155] 1. Materials and methods:

[0156] 1.1 Test diet:

[0157] The experimental group was fed the low-protein diet with the formula of Example 2 of the present invention; the control group was fed a conventional basal diet (CP≥16.0) without adding any antibiotic drugs. The composition and nutritional level of the basal diet are shown in Table 1:

[0158] Table 1: Composition and nutritional level of the basal diet (air-dried basis)

[0159]

[0160]

[0161] 1.2: Experimental design:

[0162] Select 100 "Duroc×Landrace×Yorkshire" three-way cross growing and finishing pigs with an average body weight of (30.3±1.25) kg (half male and half female), and randomly divide them into 2 groups (experimental group and control group), with 5 replicates in each group and 10 pigs in each replicate. The control group was fed the basal diet, and the experimental group was fed the fermented low-protein diet with the formula of Example 2 of the present invention.

[0163] 1.3: Feeding management:

[0164] The feeding experiment was carried out from May 21 to July 20, 2024 in the pig farm of Inner Mongolia Lifeng Breeding Co., Ltd. All experimental pigs were raised in the same pig house, fed manually and manure was removed. Feed was given 2 times a day, with free access to food and water. Keep the room temperature in the pig house between 25 °C and 28 °C, keep the pens clean and dry, and carry out procedures such as disinfection, deworming, and immunization according to the normal procedures of the pig farm.

[0165] 1.4: Measurement indicators:

[0166] 1.4.1 Growth performance: At the beginning and end of the experiment, the experimental pigs were weighed on an empty stomach (per head), and the average daily gain (ADG) was calculated; the feed intake was collected and recorded every day, and the average daily feed intake (ADFI) and feed-to-gain ratio (F / G) were calculated.

[0167] Average daily gain (ADG) = (final weight - initial weight) / number of experimental days

[0168] Average daily feed intake (ADFI) = total feed intake / number of experimental days

[0169] Feed-to-gain ratio (F / G) = average daily feed intake / average daily gain

[0170] 1.4.2 Diarrhea rate: Starting from day 0 of the pre-feeding period, the diarrhea occurrence of the fattening pigs in each group was checked and recorded every 2 days.

[0171] Diarrhea rate (%) = (number of diarrhea pigs / total number of pigs) × 100%

[0172] 1.4.3 Determination of nitrogen excretion rate:

[0173] 1.4.3.1 Collection of fecal samples: For the fecal nitrogen excretion index, select 3 days in the middle of the experiment, count the feeding amount and remaining feed amount of each replicate, calculate the feed consumption in 3 days, collect all feces per replicate every day, add 10% sulfuric acid for nitrogen fixation at 5% of the fresh fecal weight, weigh and mix the collected fecal samples, take 10% of the fresh fecal sample weight by the quartering method, dry it in an oven at 65 °C until constant weight. Mix and crush the air-dried fecal samples through a 40-mesh sieve, place them in a sealed bag and store them at -20 °C for later use.

[0174] 1.4.3.2 Collection of urine samples: Record the total amount every day when collecting urine samples, and add 10% concentrated sulfuric acid for nitrogen fixation at 5% of the urine volume. If there are foreign substances such as feed and feces during the collection process, it needs to be filtered with nylon cloth before collection. Then take 10% of the urine and put it into a plastic bottle, store it at -20 °C, and finally mix the urine of 3 days for later use.

[0175] 1.4.3.3 Determination of nitrogen content: The nitrogen content in feed, urine and fecal samples was determined using a Kjeldahl nitrogen analyzer.

[0176] 1.4.4 Determination of serum urea nitrogen: At the end of the experiment, randomly select 2 pigs (1 male and 1 female) from each replicate, fast for 24 h on an empty stomach, collect 5 mL of blood from the anterior vena cava using a vacuum blood collection tube, let the blood coagulate naturally at room temperature for 20 min, and centrifuge at 3000 rpm for 20 min. Separate the serum and store it at -20 °C for later use. The serum urea nitrogen concentration was determined using a porcine urea nitrogen (BUN) enzyme-linked immunosorbent assay kit produced by Shanghai Enzyme-linked Biotechnology Co., Ltd.

[0177] 1.4.5 Detection of intestinal flora: At the end of the experiment, 5 fresh feces were collected from each of the experimental group and the control group, and selective culture medium was used to isolate and culture to determine the numbers of lactic acid bacteria and Escherichia coli in the feces.

[0178] The specific method was to weigh 25 g of the above samples respectively, place them in a sterile conical flask containing 225 ml of sterile normal saline (with an appropriate number of glass beads pre-placed in the flask) on the sterile operating table, place them in an oscillator and shake at 150 r / min for 20 min, and make a uniform dilution of 10 -1 with sufficient shaking. Use a 1 ml sterile pipette or micropipette to suck 1 ml of the 10 -1 sample homogenate, slowly inject it along the tube wall into a sterile test tube containing 9 ml of diluent, and shake and mix well in a vortex mixer to make a sample homogenate of 10 -2 . Make 10-fold serial dilutions in the above operation sequence to prepare 10 -4 dilutions. Take 100 μL of the dilutions and inoculate them on EMB solid medium and modified MC medium respectively, spread them evenly on the surface of the petri dish, invert and culture at 37 °C for 48 h, then count the colored colonies respectively, and take the average number and multiply by 10 4 , which is the number of bacteria contained in each gram of the sample.

[0179] 1.5 Data statistics and analysis:

[0180] The experimental data were sorted out using Excel, one-way analysis of variance was performed using SPSS 20.0 software, and multiple comparisons were made in combination with the Duncan method. The experimental results were expressed as mean ± standard deviation (Mean ± SD), and P < 0.05 indicated significant differences, while P > 0.05 indicated non-significant differences.

[0181] 2. Results and analysis:

[0182] 2.1 Effects of low-protein diet on the growth performance of growing-finishing pigs:

[0183] As can be seen from Table 2, compared with the control group, the ADG of the growing pigs in the experimental group increased by 10.45% (P < 0.05), the ADFI increased by 11% (P < 0.05), and the F / G increased by 0.37% (P > 0.05). The products of the experimental group had a significant effect on promoting the growth of finishing pigs, and the difference in F / G was not significant. The following is Table 2:

[0184] Effects of low-protein diet on the growth performance of growing-finishing pigs:

[0185]

[0186] Note: Different superscript letters in the same row of data indicate significant differences (P < 0.05), and the same ones indicate non-significant differences (P > 0.05). The same applies to the following tables.

[0187] 2.2 Effect of low-protein diet on diarrhea rate of growing-finishing pigs:

[0188] As can be seen from Table 3, compared with the control group, the average diarrhea rate of growing pigs in the experimental group decreased by 75% (P < 0.05) compared with the control group. The experiment proves that the low-protein diet product of the present invention has a significant effect on diarrhea of growing-finishing pigs. The following is Table 3:

[0189] Effect of low-protein diet on diarrhea rate of growing-finishing pigs

[0190]

[0191] 2.3 Effect of low-protein diet on nitrogen excretion of growing-finishing pigs:

[0192] As can be seen from Table 4, compared with the control group, the nitrogen excretion of growing pigs in the experimental group decreased significantly (P < 0.05), the nitrogen emission reduction rate reached 36.63%, and the nitrogen utilization rate increased by 18.48% (P < 0.05). The following is Table 4:

[0193] Effect of low-protein diet on nitrogen excretion of growing-finishing pigs

[0194]

[0195]

[0196] 2.4 Effect of low-protein diet on serum urea nitrogen content of growing-finishing pigs:

[0197] As can be seen from Table 5, compared with the control group, the serum urea nitrogen concentration of growing pigs in the experimental group decreased by 26.31%, which was significantly lower than that of the control group (P < 0.05). The following is Table 5:

[0198] Effect of low-protein diet on serum urea nitrogen content of growing-finishing pigs

[0199]

[0200] 2.5 Effect of low-protein diet on fecal flora content of growing-finishing pigs:

[0201] As can be seen from Table 6, compared with the control group, the number of Escherichia coli in the feces of growing pigs in the experimental group decreased by 29.49% (P < 0.05), and the number of Lactobacillus increased by 28.68% (P < 0.05). The following is Table 6:

[0202] Effect of low-protein diet on fecal flora content of growing-finishing pigs (log10CFU / g)

[0203] Item Control group Experimental group Escherichia coli <![CDATA[7.63±0.22 a > <![CDATA[5.38±0.25 b > Lactic acid bacteria <![CDATA[6.59±0.24 a > <![CDATA[8.48±0.27 b >

[0204] 2.6 Economic benefit analysis:

[0205] As can be seen from Table 7, the compound feed per kilogram for the experimental group is 2.57 yuan, and the feed cost per kilogram of weight gain is 6.913 yuan; compared with the control group, the feed cost per kilogram is reduced by 12.88%, and the weight gain cost is reduced by 12.56%; it can be seen that feeding pigs with the low-protein diet of the present invention can reduce the feed cost and improve the economic benefit. The following is Table 7:

[0206] Economic benefit analysis

[0207]

[0208] Through feeding experiments, it is obtained that without changing the feeding environment and feeding method, the average daily weight gain of the growing-finishing pigs in the experimental group is increased by 10.45% compared with the control group, the nitrogen utilization rate in the feed is increased by 18.48%, the diarrhea rate is reduced by 75%, the nitrogen excretion amount is reduced by 36.63%, the serum urea nitrogen concentration is reduced by 26.31%, the number of Escherichia coli in pig manure is reduced by 29.49%, and the number of lactic acid bacteria is increased by 28.68%.

[0209] The crude protein (CP 13.55%) of the product of the present invention is reduced by 2.62% compared with the compound feed for conventional finishing pigs (CP 16.17%), the soybean meal usage is reduced by about 25%, the feed cost is reduced by 12.88%, and the cost per kilogram of weight gain is reduced by 12.56%.

[0210] At the same time, it can be known that the crude protein content of the product of the present invention is 13.38% - 13.55%, which meets the low-protein diet standard for finishing pigs (30 - 100 kg) in "Nutrient Requirements of Swine" (NY / T 65 - 2004).

[0211] To sum up, the fermented low-protein diet of the present invention can improve the growth performance of finishing pigs, improve the feeding environment of pig farms, improve the health of livestock, and reduce the feed cost; at the same time, through biological fermentation, the protein digestibility in the diet can be effectively improved, the amino acid balance can be improved, and the nitrogen excretion amount can be reduced. Therefore, the low-protein diet has a broad application prospect in pig production, and the breeding benefit can be effectively improved by reasonably designing the formula.

[0212] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A fermented low-protein diet for pigs, comprising a compound bacterial liquid, corn, soybean meal, wheat flour, sodium chloride, stone powder, sugarcane molasses, calcium hydrogen phosphate, choline chloride, and a premix, characterized in that: The composite bacterial liquid includes Corynebacterium glutamicum CICC23604 for producing lysine, Corynebacterium glutamicum CICC21269 for producing threonine, Corynebacterium glutamicum CICC21764 for producing valine, Saccharomyces cerevisiae CICC32203 for producing tryptophan, and Lactobacillus plantarum CICC21809 for producing lactic acid; The ingredients include 400-600 parts of corn, 100-200 parts of soybean meal, 40-60 parts of wheat flour, 15-25 parts of sugarcane molasses, 2-5 parts of sodium chloride, 10-30 parts of stone powder, 3-6 parts of calcium hydrogen phosphate, 1-2 parts of choline chloride, 4-6 parts of premix, and 200-300 parts of compound bacterial solution by mass. The composite bacterial liquid comprises, by mass, 20-30 parts of Corynebacterium glutamicum CICC23604, 20-30 parts of Corynebacterium glutamicum CICC21269, 20-30 parts of Corynebacterium glutamicum CICC21764, 30-20 parts of Saccharomyces cerevisiae CICC3220, and 10-20 parts of Lactobacillus plantarum CICC21809.

2. A fermented low-protein diet for pigs according to claim 1, characterized in that: The Corynebacterium glutamicum CICC23604 is deposited in the China Industrial Microorganism Culture Collection Center; the Corynebacterium glutamicum CICC21269 is deposited in the China Industrial Microorganism Culture Collection Center; the Corynebacterium glutamicum CICC21764 is deposited in the China Industrial Microorganism Culture Collection Center; the Saccharomyces cerevisiae CICC32203 is deposited in the China Industrial Microorganism Culture Collection Center; the Lactobacillus plantarum CICC21809 is deposited in the China Industrial Microorganism Culture Collection Center, and is used to improve the growth performance and intestinal flora of piglets; The Corynebacterium glutamicum secretes essential amino acids to optimize the amino acid balance of low-protein diets for fermented pigs; the Saccharomyces cerevisiae is used to provide tryptophan and promote nutrient absorption; the Lactobacillus plantarum inhibits harmful bacteria and improves the intestinal environment by producing lactic acid; the sugar in the sugarcane molasses is used to promote microbial metabolism and increase amino acid production; the choline chloride is used to promote amino acid recycling and reduce feed costs, and the amino acids secreted by the Corynebacterium glutamicum are used to provide a nitrogen source for Saccharomyces cerevisiae and promote its production of tryptophan; the lactic acid produced by the Lactobacillus plantarum is used to lower the pH value, inhibit Escherichia coli, and create a suitable environment for the Corynebacterium glutamicum.

3. A fermented low-protein diet for pigs according to claim 1, characterized in that: The fermented low-protein diet for pigs has a lysine content of 1.12%-1.28%, a methionine content of 0.35%-0.37%, a threonine content of 0.76%-0.91%, a tryptophan content of 0.2%-0.24%, an isoleucine content of 0.53%-0.55%, a valine content of 0.87%-1.04%, a crude protein content of 13.38%-13.55%, a total acid content of 1.92%-2.43% in terms of lactic acid, and a total number of functional live bacteria of 2.7×10 8 -3.5×10 8 CFU / g.

4. A fermented low-protein diet for pigs according to claim 1, characterized in that: The premix is ​​prepared by blending vitamin A, vitamin D3, vitamin E, vitamin K3, vitamin B1, vitamin B2, vitamin B6, vitamin B12, nicotinamide, calcium pantothenate, folic acid, biotin, ferrous sulfate, copper sulfate, zinc sulfate, manganese sulfate, calcium iodate and sodium selenite.

5. A method for preparing a fermented low-protein diet for pigs, using a fermented low-protein diet for pigs as claimed in any one of claims 1 to 4, characterized in that: The steps include: S1: preparing bacterial liquids of Corynebacterium glutamicum CICC23604, Corynebacterium glutamicum CICC21269, Corynebacterium glutamicum CICC21764, Saccharomyces cerevisiae CICC32203 and Lactobacillus plantarum CICC21809 respectively; S101: wherein the bacterial solution of Corynebacterium glutamicum CICC23604 is prepared as follows: Preparation of liquid seed culture medium: Add 25-35g of peptone, 4-6g of beef extract powder, 1-2g of glucose, and 4-6g of NaCl into 1000mL of distilled water, stir until completely dissolved, adjust the pH to 7.0±0.2, and sterilize at 115-121℃ for 15-20min; Preparation of liquid fermentation medium: add 25-35kg of peptone, 4-6kg of beef extract powder, 1-2kg of glucose, and 4-6kg of NaCl into 1000L of pure water, stir until completely dissolved, adjust the pH to 7.0±0.2, and sterilize at 115-121°C for 15-20min; Culture conditions: The method comprises seed liquid culture: inoculating the slant strain of Corynebacterium glutamicum CICC23604 into the liquid seed culture medium at a ratio of 1 ring / 50-100 ml, with the temperature at 28-32° C., the rotation speed at 150-200 r / min, and the shaking culture for 18-30 hours; The fermentation liquid culture is further comprised of: inoculating the above seed liquid into a fermentation tank containing a liquid fermentation medium at a volume ratio of 5%-15%, the temperature is 28-32°C, sterile air is introduced, and the ventilation ratio is 0.5-1.5 (m 3 / m 3 ·min), tank pressure 0.01-0.05MPa, rotation speed 150-200r / min, culture for 18-30h, and obtain Corynebacterium glutamicum CICC23604 bacterial solution; S102: The bacterial solution of Corynebacterium glutamicum CICC21269 was prepared as follows: Preparation of liquid seed culture medium: Add 4-6g of peptone, 2-4g of beef extract powder, and 4-6g of NaCl to 1000mL of distilled water, stir until completely dissolved, adjust the pH to 7.0±0.2, and sterilize at 115-121℃ for 15-20min; Preparation of liquid fermentation medium: add 4-6 kg of peptone, 2-4 kg of beef extract powder, and 4-6 kg of NaCl into 1000 L of pure water, stir until completely dissolved, adjust the pH to 7.0±0.2, and sterilize at 115-121°C for 15-20 min; Culture conditions: Seed liquid culture: Inoculate the slant strain of Corynebacterium glutamicum CICC21269 into the liquid seed culture medium at a ratio of 1 ring / 50-100 ml, culture at a temperature of 28-32°C, a rotation speed of 150-200 r / min, and shake for 18-30 hours; Fermentation broth culture: inoculate the above seed liquid into a fermentation tank containing liquid fermentation medium at a volume ratio of 5%-15%, the temperature is 28-32°C, sterile air is introduced, and the ventilation ratio is 0.5-1.5 (m 3 / m 3 ·min), tank pressure 0.01-0.05MPa, rotation speed 150-200r / min, culture for 18-30h, and obtain Corynebacterium glutamicum CICC21269 bacterial solution; S103: The preparation method of the bacterial solution of Corynebacterium glutamicum CICC21764 is the same as the preparation method of the bacterial solution of Corynebacterium glutamicum CICC21269; S104: Saccharomyces cerevisiae CICC32203 bacterial solution was prepared as follows: Preparation of liquid seed culture medium: Add 25-35g malt extract powder and 2-5g soy peptone into 1000mL distilled water, stir until completely dissolved, adjust the pH to 5.6±0.2, and sterilize at 115-121℃ for 15-20min; Preparation of liquid fermentation medium: add 15-25 kg of peptone, 5-15 kg of yeast extract, and 15-25 kg of glucose into 1000 L of pure water, stir until completely dissolved, adjust the pH to 5.6±0.2, and sterilize at 115-121°C for 15-20 min; Culture conditions: Seed liquid culture: Inoculate the slant strain of Saccharomyces cerevisiae CICC32203 into the liquid seed culture medium at a ratio of 1 ring / 50-100 ml, culture at a temperature of 25-30°C, a rotation speed of 150-200 r / min, and shake for 18-30 hours; Fermentation broth culture: inoculate the above seed liquid into a fermentation tank containing liquid fermentation medium at a volume ratio of 5%-15%, the temperature is 25-30°C, sterile air is introduced, and the ventilation ratio is 0.5-1.5 (m 3 / m 3 ·min), tank pressure 0.01-0.05MPa, rotation speed 150-200r / min, culture for 18-30h, and obtain brewer's yeast CICC32203 bacterial liquid; S105: The bacterial solution of Lactobacillus plantarum CICC21809 was prepared as follows: Preparation of liquid seed culture medium: add 8-12g of casein peptone, 8-12g of beef extract, 3-7g of yeast extract powder, 15-25g of glucose, 3-7g of sodium acetate, 1-2g of triammonium citrate, 1-2g of Tween80, 1-3g of K2HPO4, 0.1-0.3g of MgSO4.7H2O, and 0.03-0.07g of MnSO4.H2O into 1000mL of distilled water, stir until completely dissolved, adjust the pH to 6.5±0.2, and sterilize at 115-121°C for 15-20min; Preparation of liquid fermentation medium: add 8-12 kg of casein peptone, 8-12 kg of beef extract, 3-7 kg of yeast extract powder, 15-25 kg of glucose, 3-7 kg of sodium acetate, 1-2 kg of triammonium citrate, 1-2 kg of Tween80, 1-3 kg of K2HPO4, 0.1-0.3 kg of MgSO4.7H2O, and 0.03-0.07 kg of MnSO4H2O to 1000 L of pure water, stir until completely dissolved, adjust the pH to 6.5±0.2, and sterilize at 115-121°C for 15-20 min; Culture conditions: Seed liquid culture: Inoculate the slant strain of Lactobacillus plantarum CICC21809 into the liquid seed culture medium at a ratio of 1 ring / 50-100 ml, culture at a temperature of 32-37°C, a rotation speed of 100-150 r / min, and shake for 18-30 hours; Fermentation broth culture: inoculate the above seed liquid into a fermentation tank containing liquid fermentation medium at a volume ratio of 5%-15%, the temperature is 32-37°C, sterile air is introduced, and the ventilation ratio is 0.5-1.5 (m 3 / m 3 ·min), tank pressure 0.01-0.05MPa, rotation speed 100-150r / min, culture for 18-30h, and obtain plant lactobacillus liquid; S2: Weigh and compound, and compound the prepared Corynebacterium glutamicum CICC23604 bacterial solution, Corynebacterium glutamicum CICC21269 bacterial solution, Corynebacterium glutamicum CICC21764 bacterial solution, Saccharomyces cerevisiae CICC32203 bacterial solution and Lactobacillus plantarum CICC21809 bacterial solution by volume, wherein 20-30 parts of Corynebacterium glutamicum CICC23604 bacterial solution, 20-30 parts of Corynebacterium glutamicum CICC21269 bacterial solution, 20-30 parts of Corynebacterium glutamicum CICC21764 bacterial solution, 10-20 parts of Saccharomyces cerevisiae CICC32203 bacterial solution, and 10-20 parts of Lactobacillus plantarum CICC21809 bacterial solution, thereby preparing a composite bacterial solution; S3: Preparation of a solid fermentation carrier: 400-600 parts of corn, 100-200 parts of soybean meal, 40-60 parts of wheat flour, 2-5 parts of sodium chloride, 10-30 parts of stone powder, 15-25 parts of sugarcane molasses, 3-6 parts of calcium hydrogen phosphate, 1-2 parts of choline chloride and 4-6 parts of premix are fully mixed to prepare a solid fermentation carrier; S4: Mixing treatment, spraying the composite bacterial liquid uniformly into the solid fermentation carrier according to a mass ratio of 1:3-1:4, fully mixing, placing it in a solid fermentation equipment for fermentation under aerobic conditions and a constant temperature of 30-32°C for 5d-7d, packaging after fermentation, and preparing a fermented low-protein diet for pigs, wherein the fermented low-protein diet for pigs can increase the average daily weight gain of growing and fattening pigs by 9%-12%; increase nitrogen utilization by 15%-20%; reduce diarrhea rate by 70%-80%; reduce nitrogen excretion by 30%-40%, reduce serum urea nitrogen concentration by 20%-40%; reduce the number of Escherichia coli in pig manure by 25%-35%, and increase the number of lactic acid bacteria in pig manure by 25%-35%; Solid-state fermentation is divided into two stages: the first stage is 0-3 days, with the temperature controlled at 30°C and the humidity at 60% to promote the secretion of amino acids; the second stage is 4-7 days, with the temperature raised to 32°C and the humidity lowered to 50% to promote the proliferation of lactic acid bacteria.

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