Low-temperature fermentation liquid feed and preparation method thereof

Abstract

The invention provides a low-temperature fermentation liquid feed and a preparation method thereof, and relates to the technical field of livestock feed preparation, the low-temperature fermentation liquid feed comprises main raw materials, auxiliary raw materials, additives and strains, the main raw materials comprise 380-420 parts of corn flour, 190-210 parts of soybean meal and 142-158 parts of wheat bran; the auxiliary raw materials comprise 95-108 parts of apple pomace, 70-80 parts of carrot pomace and 70-80 parts of pumpkin pomace; the additives comprise 4.5 to 6 parts of a low-temperature protective agent, a compound mineral premix, an enzyme preparation, 2.7 to 3.3 parts of chitosan microcapsule lysine, 0.045 to 0.055 part of # imgabs0 # nanoparticles and 0.08 to 0.12 part of nattokinase, and the strains comprise 40 to 60 parts of cold-resistant lactic acid bacteria and 18 to 22 parts of saccharomycetes. The method has the beneficial effects that through the synergistic effect of low-temperature enzymolysis and the magnetic field, the fermentation efficiency at low temperature is remarkably improved, and the energy consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of animal feed preparation, in particular to a low-temperature fermented liquid feed and a preparation method thereof. Background Art

[0002] Liquid feed, a crucial form of nutrition in modern livestock and poultry farming, is widely used in the pig industry due to its palatability, high digestibility, and ability to precisely regulate nutrition. Traditional liquid feeds typically utilize high-temperature fermentation processes, relying on mesophilic microorganisms such as Lactobacillus to metabolize and produce acid for feed preservation and degradation of anti-nutritional factors. However, high-temperature fermentation has significant drawbacks: First, continuous heating results in energy consumption accounting for over 30% of production costs; second, high temperatures can easily lead to bacterial contamination, such as the proliferation of Bacillus spp., necessitating the addition of chemical preservatives, which can potentially cause an imbalance in the animal's intestinal flora. In recent years, low-temperature fermentation technology has garnered attention for its potential for energy savings and reduced antibiotic reliance. However, issues such as insufficient microbial metabolic activity, prolonged fermentation cycles, and unstable final product quality under low temperatures have severely hampered its industrial application. Existing technologies attempt to optimize liquid feeds through strain modification, such as screening for cold-resistant strains or adding exogenous enzymes such as low-temperature amylase. However, single approaches often struggle to balance fermentation efficiency and cost control, necessitating the addition of systematic solutions.

[0003] Current low-temperature fermentation liquid feed technology faces three core bottlenecks: First, the adaptability of bacterial agents is insufficient. Conventional cold-resistant lactic acid bacteria produce only one-third of the acid production rate of mesophilic bacteria at 15°C, and are easily inhibited by anti-nutritional factors in the raw materials. Second, there is an imbalance in nutrient supply. The low temperature environment causes the microbial carbon source utilization rate to drop by 20-40%, and the release rate of existing slow-release technology at low temperatures does not match the bacterial needs. Third, the risk of contamination is exacerbated. The low-temperature fermentation cycle is extended to 5-7 days, providing a proliferation window for mold and pathogens. Existing antibacterial methods will further inhibit the activity of the target bacterial population. These shortcomings make it difficult for existing low-temperature fermentation processes to achieve production efficiency comparable to high-temperature processes while ensuring feed hygiene and safety, severely limiting the industrialization and promotion of this technology.

[0004] How to solve the above technical problems is the subject faced by the present invention. Summary of the Invention

[0005] In order to address the deficiencies of the prior art, the present invention provides a low-temperature fermented liquid feed and a preparation method thereof, which significantly improves the fermentation efficiency at low temperatures and reduces energy consumption through the synergistic effect of low-temperature enzymatic hydrolysis and a magnetic field.

[0006] The technical solution adopted by the present invention to solve the technical problem is as follows: the present invention provides a low-temperature fermented liquid feed, including main raw materials, auxiliary raw materials, additives and bacterial strains, wherein the main raw materials include 380-420 parts of corn flour, 190-210 parts of soybean meal, and 142-158 parts of wheat bran; the auxiliary raw materials include 95-108 parts of apple pomace, 70-80 parts of carrot pomace, and 70-80 parts of pumpkin pomace; the additives include 4.5-6 parts of cryoprotectant, composite mineral premix, enzyme preparation, 2.7-3.3 parts of chitosan microcapsule lysine, 0.045-0.055 parts of nanoparticles and 0.08-0.12 parts of nattokinase; the corn flour is ground through a 60-mesh sieve, the soybean meal is ground through a 40-mesh sieve, and the wheat bran is ground through a 30-mesh sieve. The apple pomace is free of rotten parts, the carrot pomace is peeled, and the pumpkin pomace is deseeded and steamed at >100°C for 8-10 minutes to soften; the apple, carrot, and pumpkin pomace are all crushed to a particle size of ≤3 mm.

[0007] The cryoprotectant is one or more of trehalose, sucrose fatty acid ester, hydroxyproline or polyglycerol fatty acid ester. The enzyme preparation includes 0.9-1.1 parts of low-temperature α-amylase, 0.45-0.55 parts of neutral protease, 0.045-0.055 parts of pectinase and 0.027-0.033 parts of cellulase. The particle size of the nanoparticles is 50 nm.

[0008] The composite mineral premix comprises 2.9-3.5 parts of ferrous sulfate, 2.3-2.8 parts of zinc sulfate, 0.7-0.9 parts of copper sulfate, 1.4-1.7 parts of manganese sulfate and 1.8-2.2 parts of carrier medical stone powder.

[0009] The bacterial strains include 40-60 parts of cold-resistant lactic acid bacteria and 18-22 parts of yeast.

[0010] A method for preparing low-temperature fermented liquid feed comprises the following steps: S1. Pretreatment of abandoned fruit tree residues Remove the rotten part of the apple pomace, peel the carrot pomace, and remove the seeds from the pumpkin pomace, then steam at >100°C for 8-10 minutes to soften them. Mix the apple pomace, carrot pomace, and pumpkin pomace, and process them through a hammer crusher to a particle size of ≤3mm. S2, enzymatic liquefaction Pectinase and cellulase were added, and the pH was adjusted to 4.5 with citric acid. The mixture was stirred at 30 rpm in a constant temperature water bath at 35 ± 1 °C for 2 h. S3, main raw materials mixed conditioning S31, corn flour, soybean meal, and wheat bran were put into a twin-shaft paddle mixer, and pre-mixed composite mineral premix and cryoprotectant were added, and mixed for 15 minutes at a speed of 25 rpm; S32, add pretreated fruit and vegetable residues, start the mixer and slowly inject purified water at a water-to-material ratio of 1.86:1, spray add 5% NaHCO3 solution, and continue mixing for 20 minutes until the pH reaches 6.0±0.2; S4, low temperature enzymatic hydrolysis S41. Add low-temperature α-amylase and stir at 40±1°C for 1.5 hours at 50 rpm until the iodine solution turns reddish brown and the starch is completely degraded. S42, add neutral protease, stir at 30±1℃ for 1 hour, at 30 rpm, until the free amino acid content is ≥2.5% as determined by the ninhydrin method; S5. Inoculation and fermentation of cold-resistant bacteria S51 and lactic acid bacteria were cultured in MRS medium at 15°C for 24 h, and yeast was cultured in YPD medium at 25°C for 18 h with shaking at 120 rpm. S52, inoculate the activated bacteria into the material after enzymatic hydrolysis in step S4, and simultaneously add chitosan microcapsule lysine, The nanoparticles were ultrasonically dispersed in 5 parts of sterile water and simultaneously added to the material after enzymatic hydrolysis in step S4; S53, pre-fermentation stage temperature 25 ± 1 ° C, 24 hours, to promote rapid proliferation of bacteria; The main fermentation stage was carried out at a temperature of 15±1°C for 72 hours, with slow fermentation at low temperature. A 0.3T static magnetic field was applied to the periphery of the fermenter to assist in the pH value to drop naturally below 4.5, triggering the release of lysine. S6. Termination of fermentation and post-processing S61. Raise the temperature of the fermented material in S52 to 60±1°C and hold for 10 minutes to inactivate the enzyme and bacteria, and immediately cool to below 25°C; S62, add nattokinase and mix well; S63. Fill in sealed PE bags, evacuate to -0.09 MPa, and store at 4-15℃ away from light.

[0011] The beneficial effects of the present invention are as follows: the present invention effectively solves the problems of low metabolic rate and long cycle of traditional low-temperature fermentation through a composite low-temperature enzymolysis-fermentation synergistic system, adopts a step-by-step enzymolysis process to pre-degrade starch and protein, and provides easily usable small molecular carbon and nitrogen sources for psychrotrophic bacteria, thereby improving the lactic acid yield at 15°C compared to conventional low-temperature fermentation. At the same time, magnetic field assistance and The synergistic effect of nanoparticles enhances the permeability of bacterial cell membranes, further shortens the fermentation cycle, and achieves efficiency comparable to medium-temperature fermentation while reducing energy consumption. This solves the pain point of insufficient metabolic activity of low-temperature bacteria and avoids the drawbacks of traditional processes that rely on high-temperature heating.

[0012] To address the problem of mismatch between nutrient release and bacterial needs during low-temperature fermentation, the present invention introduces pH-responsive chitosan microencapsulated lysine, which automatically releases limiting amino acids in the later stage of fermentation, accurately meeting the nutritional needs of microorganisms during the logarithmic growth period. In addition, a synergistic antibacterial system of nattokinase and discarded fruit and vegetable enzymes is used to replace traditional chemical preservatives. It can still effectively inhibit Escherichia coli and mold contamination at 15°C without affecting the activity of the target bacterial flora, overcoming the current defects of low-temperature fermentation that is prone to contamination and relies on antibiotics or organic acids.

[0013] At the same time, this technology not only reduces the cost of raw materials by integrating discarded fruit and vegetable residues as fermentation substrates, but also uses their natural vitamins and minerals to make up for the nutritional loss of low-temperature fermentation. The optimized ratio of complex mineral premix and trehalose further reduces the amount of trace elements added, avoiding the antagonistic effect caused by excessive addition. Compared with the existing solutions that rely on high-cost enzyme preparations or genetically engineered bacteria, this solution uses all conventional industrial-grade raw materials, is easy to scale up, and provides an economically feasible low-temperature fermentation technology path for the breeding industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Graph showing the fermentation efficiency of various embodiments of the present invention and comparative examples at a low temperature of 15°C.

[0015] Figure 2 The figures are for evaluating the antibacterial performance and safety of various embodiments of the present invention and comparative examples.

[0016] Figure 3 This is a diagram showing the effects of the embodiments of the present invention and the comparative example on the growth performance and intestinal tract of piglets. DETAILED DESCRIPTION

[0017] In order to clearly illustrate the technical features of this solution, the solution is described below through specific implementation methods.

[0018] Example 1 This embodiment is a low-temperature fermented liquid feed, comprising a main raw material, auxiliary raw materials, additives, and bacterial strains, wherein the main raw materials include 400 parts of corn flour, 200 parts of soybean meal, and 150 parts of wheat bran, the corn flour is crushed through a 60-mesh sieve, the soybean meal is crushed through a 40-mesh sieve, and the 150 parts of wheat bran are crushed through a 30-mesh sieve, and the auxiliary raw materials include 100 parts of apple pomace, 75 parts of carrot pomace, and 75 parts of pumpkin pomace, wherein the apple pomace is free of rotten parts, the carrot pomace is peeled and crushed to a particle size of ≤3 mm, and the pumpkin pomace is deseeded and steamed at 100° C. for 10 minutes to soften; Additives include 5 parts of cryoprotectant, composite mineral premix, enzyme preparation, 3 parts of chitosan microcapsule lysine, 0.05 parts of nanoparticles, 0.1 parts of nattokinase, wherein the low-temperature protective agent is trehalose, the enzyme preparation includes 1 part of low-temperature α-amylase, 0.5 parts of neutral protease, 0.05 parts of pectinase, and 0.03 parts of cellulase. The nanoparticles have a particle size of 50 nm, and the composite mineral premix includes 3.2 parts of ferrous sulfate, 2.5 parts of zinc sulfate, 0.8 parts of copper sulfate, 1.5 parts of manganese sulfate, and 2.0 parts of carrier medical stone powder; The bacterial strains include 50 parts of cold-resistant lactic acid bacteria and 20 parts of yeast.

[0019] A method for preparing low-temperature fermented liquid feed comprises the following steps: S1. Pretreatment of abandoned fruit tree residues Remove the rotten part of apple pomace, peel the carrot pomace, and remove the seeds of pumpkin pomace, then steam at 100°C for 10 minutes to soften them. Mix the apple pomace, carrot pomace, and pumpkin pomace, and process them through a hammer crusher to a particle size of ≤3mm. S2, enzymatic liquefaction Add 0.05 parts of pectinase and 0.03 parts of cellulase, adjust the pH to 4.5 with citric acid, and stir in a constant temperature water bath at 35±1°C at 30 rpm for 2 hours; S3, main raw materials mixed conditioning S31, put 400 parts of corn flour, 200 parts of soybean meal, and 150 parts of wheat bran into a twin-shaft paddle mixer, add the premixed composite mineral premix, add 5 parts of trehalose, and mix for 15 minutes at a speed of 25 rpm; S32, add 250 parts of pretreated fruit and vegetable residues, start the mixer and slowly inject purified water at a water-to-material ratio of 1.86:1, spray add 5% NaHCO3 solution, and continue mixing for 20 minutes until the pH reaches 6.0±0.2; S4, low temperature enzymatic hydrolysis S41. Add 1 part of low-temperature α-amylase and stir at 40±1°C for 1.5 hours at 50 rpm until the iodine solution turns reddish brown and the starch is completely degraded. S42, add 0.5 parts of neutral protease, stir at 30±1℃ for 1 hour, rotate at 30 rpm, until the free amino acid content is ≥2.5% as determined by the ninhydrin method; S5. Inoculation and fermentation of cold-resistant bacteria S51 and lactic acid bacteria were cultured in MRS medium at 15°C for 24 h, and yeast was cultured in YPD medium at 25°C for 18 h with shaking at 120 rpm. S52, inoculate the activated bacteria into the material after enzymatic hydrolysis in step S4, and simultaneously add 3 parts of chitosan microcapsule lysine, 0.05 parts of nanoparticles were ultrasonically dispersed in 5 parts of sterile water and simultaneously added to the material after enzymatic hydrolysis in step S4; S53, pre-fermentation stage, temperature 25±1°C, 24 hours; The main fermentation stage was conducted at a temperature of 15±1°C for 72 hours. A 0.3T static magnetic field was applied to the periphery of the fermenter to assist in the pH value to drop naturally below 4.5. S6. Termination of fermentation and post-processing S61. Raise the temperature of the fermented material in S52 to 60±1°C and hold for 10 minutes, then immediately cool to below 25°C; S62, add 0.1 parts of nattokinase and mix well; S63. Fill in sealed PE bags, evacuate to -0.09 MPa, and store at 4-15℃ away from light.

[0020] Example 2 This embodiment is a low-temperature fermented liquid feed, comprising a main raw material, auxiliary raw materials, additives, and bacterial strains, wherein the main raw materials include 400 parts of corn flour, 200 parts of soybean meal, and 150 parts of wheat bran, the corn flour is crushed through a 60-mesh sieve, the soybean meal is crushed through a 40-mesh sieve, and the 150 parts of wheat bran are crushed through a 30-mesh sieve, and the auxiliary raw materials include 100 parts of apple pomace, 75 parts of carrot pomace, and 75 parts of pumpkin pomace, wherein the apple pomace is free of rotten parts, the carrot pomace is peeled and crushed to a particle size of ≤3 mm, and the pumpkin pomace is deseeded and steamed at 100° C. for 10 minutes to soften; Additives include 5 parts of cryoprotectant, composite mineral premix, enzyme preparation, 3 parts of chitosan microcapsule lysine, 0.05 parts of nanoparticles, 0.1 parts of nattokinase, wherein the low-temperature protective agent is trehalose, the enzyme preparation includes 1 part of low-temperature α-amylase, 0.5 parts of neutral protease, 0.05 parts of pectinase, and 0.03 parts of cellulase. The nanoparticles have a particle size of 50 nm, and the composite mineral premix includes 3.2 parts of ferrous sulfate, 2.5 parts of zinc sulfate, 0.8 parts of copper sulfate, 1.5 parts of manganese sulfate, and 2.0 parts of carrier medical stone powder; The bacterial strains include 60 parts of cold-resistant lactic acid bacteria and 15 parts of yeast.

[0021] A method for preparing low-temperature fermented liquid feed comprises the following steps: S1. Pretreatment of abandoned fruit tree residues Remove the rotten part of apple pomace, peel the carrot pomace, and remove the seeds of pumpkin pomace, then steam at 100°C for 10 minutes to soften them. Mix the apple pomace, carrot pomace, and pumpkin pomace, and process them through a hammer crusher to a particle size of ≤3mm. S2, enzymatic liquefaction Add 0.05 parts of pectinase and 0.03 parts of cellulase, adjust the pH to 4.5 with citric acid, and stir in a constant temperature water bath at 35±1°C at 30 rpm for 2 hours; S3, main raw materials mixed conditioning S31, put 400 parts of corn flour, 200 parts of soybean meal, and 150 parts of wheat bran into a twin-shaft paddle mixer, add the premixed composite mineral premix, add 5 parts of trehalose, and mix for 15 minutes at a speed of 25 rpm; S32, add 250 parts of pretreated fruit and vegetable residues, start the mixer and slowly inject purified water at a water-to-material ratio of 1.86:1, spray add 5% NaHCO3 solution, and continue mixing for 20 minutes until the pH reaches 6.0±0.2; S4, low temperature enzymatic hydrolysis S41. Add 1 part of low-temperature α-amylase and stir at 40±1°C for 1.5 hours at 50 rpm until the iodine solution turns reddish brown and the starch is completely degraded. S42, add 0.5 parts of neutral protease, stir at 30±1℃ for 1 hour, rotate at 30 rpm, until the free amino acid content is ≥2.5% as determined by the ninhydrin method; S5. Inoculation and fermentation of cold-resistant bacteria S51 and lactic acid bacteria were cultured in MRS medium at 15°C for 24 h, and yeast was cultured in YPD medium at 25°C for 18 h with shaking at 120 rpm. S52, inoculate the activated bacteria into the material after enzymatic hydrolysis in step S4, and simultaneously add 3 parts of chitosan microcapsule lysine, 0.05 parts of nanoparticles were ultrasonically dispersed in 5 parts of sterile water and simultaneously added to the material after enzymatic hydrolysis in step S4; S53, pre-fermentation stage, temperature 25±1°C, 24 hours; The main fermentation stage was conducted at a temperature of 16±1°C for 72 hours. A 0.3T static magnetic field was applied to the periphery of the fermenter to assist in the pH naturally decreasing to below 4.5. S6. Termination of fermentation and post-processing S61. Raise the temperature of the fermented material in S52 to 60±1°C and hold for 10 minutes, then immediately cool to below 25°C; S62, add 0.1 parts of nattokinase and mix well; S63. Fill in sealed PE bags, evacuate to -0.09 MPa, and store at 4-15℃ away from light.

[0022] Example 3 This embodiment is a low-temperature fermented liquid feed, comprising a main raw material, auxiliary raw materials, additives, and bacterial strains, wherein the main raw materials include 400 parts of corn flour, 200 parts of soybean meal, and 150 parts of wheat bran, the corn flour is crushed through a 60-mesh sieve, the soybean meal is crushed through a 40-mesh sieve, and the 150 parts of wheat bran are crushed through a 30-mesh sieve, and the auxiliary raw materials include 100 parts of apple pomace, 75 parts of carrot pomace, and 75 parts of pumpkin pomace, wherein the apple pomace is free of rotten parts, the carrot pomace is peeled and crushed to a particle size of ≤3 mm, and the pumpkin pomace is deseeded and steamed at 100° C. for 10 minutes to soften; Additives include 5 parts of cryoprotectant, composite mineral premix, enzyme preparation, 3 parts of chitosan microcapsule lysine, 0.05 parts of nanoparticles, 0.1 parts of nattokinase, wherein the low-temperature protective agent is trehalose, and the enzyme preparation includes 1.2 parts of low-temperature α-amylase, 0.5 parts of neutral protease, 0.05 parts of pectinase, and 0.03 parts of cellulase. The nanoparticles have a particle size of 50 nm, and the composite mineral premix includes 3.2 parts of ferrous sulfate, 2.5 parts of zinc sulfate, 0.8 parts of copper sulfate, 1.5 parts of manganese sulfate, and 2.0 parts of carrier medical stone powder; The bacterial strains include 50 parts of cold-resistant lactic acid bacteria and 20 parts of yeast.

[0023] A method for preparing low-temperature fermented liquid feed comprises the following steps: S1. Pretreatment of abandoned fruit tree residues Remove the rotten part of apple pomace, peel the carrot pomace, and remove the seeds of pumpkin pomace, then steam at 100°C for 10 minutes to soften them. Mix the apple pomace, carrot pomace, and pumpkin pomace, and process them through a hammer crusher to a particle size of ≤3mm. S2, enzymatic liquefaction Add 0.05 parts of pectinase and 0.03 parts of cellulase, adjust the pH to 4.5 with citric acid, and stir in a constant temperature water bath at 35±1°C at 30 rpm for 2 hours; S3, main raw materials mixed conditioning S31, put 400 parts of corn flour, 200 parts of soybean meal, and 150 parts of wheat bran into a twin-shaft paddle mixer, add the premixed composite mineral premix, add 5 parts of trehalose, and mix for 15 minutes at a speed of 25 rpm; S32, add 250 parts of pretreated fruit and vegetable residues, start the mixer and slowly inject purified water at a water-to-material ratio of 1.86:1, spray add 5% NaHCO3 solution, and continue mixing for 20 minutes until the pH reaches 6.0±0.2; S4, low temperature enzymatic hydrolysis S41. Add 1.2 parts of low-temperature α-amylase and stir at 42±1°C for 1 hour at 50 rpm until the iodine solution turns reddish brown and the starch is completely degraded. S42, add 0.5 parts of neutral protease, stir at 30±1℃ for 1 hour, rotate at 30 rpm, until the free amino acid content is ≥2.5% as determined by the ninhydrin method; S5. Inoculation and fermentation of cold-resistant bacteria S51 and lactic acid bacteria were cultured in MRS medium at 15°C for 24 h, and yeast was cultured in YPD medium at 25°C for 18 h with shaking at 120 rpm. S52, inoculate the activated bacteria into the material after enzymatic hydrolysis in step S4, and simultaneously add 3 parts of chitosan microcapsule lysine, 0.05 parts of nanoparticles were ultrasonically dispersed in 5 parts of sterile water and simultaneously added to the material after enzymatic hydrolysis in step S4; S53, pre-fermentation stage, temperature 25±1°C, 24 hours; The main fermentation stage was conducted at a temperature of 15±1°C for 72 hours. A 0.3T static magnetic field was applied to the periphery of the fermenter to assist in the pH value to drop naturally below 4.5. S6. Termination of fermentation and post-processing S61. Raise the temperature of the fermented material in S52 to 60±1°C and hold for 10 minutes, then immediately cool to below 25°C; S62, add 0.1 parts of nattokinase and mix well; S63. Fill in sealed PE bags, evacuate to -0.09 MPa, and store at 4-15℃ away from light.

[0024] Example 4 This embodiment is a low-temperature fermented liquid feed, comprising a main raw material, auxiliary raw materials, additives, and bacterial strains, wherein the main raw materials include 400 parts of corn flour, 200 parts of soybean meal, and 150 parts of wheat bran, the corn flour is crushed through a 60-mesh sieve, the soybean meal is crushed through a 40-mesh sieve, and the 150 parts of wheat bran are crushed through a 30-mesh sieve, and the auxiliary raw materials include 100 parts of apple pomace, 75 parts of carrot pomace, and 75 parts of pumpkin pomace, wherein the apple pomace is free of rotten parts, the carrot pomace is peeled and crushed to a particle size of ≤3 mm, and the pumpkin pomace is deseeded and steamed at 100° C. for 10 minutes to soften; Additives include 5 parts of cryoprotectant, composite mineral premix, enzyme preparation, 3 parts of chitosan microcapsule lysine, 0.05 parts of nanoparticles, 0.1 parts of nattokinase, wherein the low-temperature protective agent is sucrose fatty acid ester, the enzyme preparation includes 1 part of low-temperature α-amylase, 0.5 parts of neutral protease, 0.05 parts of pectinase, and 0.03 parts of cellulase, The nanoparticles have a particle size of 50 nm, and the composite mineral premix includes 3.2 parts of ferrous sulfate, 2.5 parts of zinc sulfate, 0.8 parts of copper sulfate, 1.5 parts of manganese sulfate, and 2.0 parts of carrier medical stone powder; The bacterial strains include 50 parts of cold-resistant lactic acid bacteria and 20 parts of yeast.

[0025] A method for preparing low-temperature fermented liquid feed comprises the following steps: S1. Pretreatment of abandoned fruit tree residues Remove the rotten part of apple pomace, peel the carrot pomace, and remove the seeds of pumpkin pomace, then steam at 100°C for 10 minutes to soften them. Mix the apple pomace, carrot pomace, and pumpkin pomace, and process them through a hammer crusher to a particle size of ≤3mm. S2, enzymatic liquefaction Add 0.05 parts of pectinase and 0.03 parts of cellulase, adjust the pH to 4.5 with citric acid, and stir in a constant temperature water bath at 35±1°C at 30 rpm for 2 hours; S3, main raw materials mixed conditioning S31, 400 parts of corn flour, 200 parts of soybean meal, and 150 parts of wheat bran were put into a twin-shaft paddle mixer, and a premixed composite mineral premix was added, followed by 5 parts of sucrose fatty acid ester, and the mixture was mixed for 25 minutes at a speed of 25 rpm; S32, add 250 parts of pretreated fruit and vegetable residues, start the mixer and slowly inject purified water at a water-to-material ratio of 1.86:1, spray add 5% NaHCO3 solution, and continue mixing for 20 minutes until the pH reaches 6.0±0.2; S4, low temperature enzymatic hydrolysis S41. Add 1 part of low-temperature α-amylase and stir at 40±1°C for 1.5 hours at 50 rpm until the iodine solution turns reddish brown and the starch is completely degraded. S42, add 0.5 parts of neutral protease, stir at 30±1℃ for 1 hour, rotate at 30 rpm, until the free amino acid content is ≥2.5% as determined by the ninhydrin method; S5. Inoculation and fermentation of cold-resistant bacteria S51 and lactic acid bacteria were cultured in MRS medium at 15°C for 24 h, and yeast was cultured in YPD medium at 25°C for 18 h with shaking at 120 rpm. S52, inoculate the activated bacteria into the material after enzymatic hydrolysis in step S4, and simultaneously add 3 parts of chitosan microcapsule lysine, 0.05 parts of nanoparticles were ultrasonically dispersed in 5 parts of sterile water and simultaneously added to the material after enzymatic hydrolysis in step S4; S53, pre-fermentation stage, temperature 25±1°C, 24 hours; The main fermentation stage was conducted at a temperature of 15±1°C for 72 hours. A 0.3T static magnetic field was applied to the periphery of the fermenter to assist in the pH value to drop naturally below 4.5. S6. Termination of fermentation and post-processing S61. Raise the temperature of the fermented material in S52 to 60±1°C and hold for 10 minutes, then immediately cool to below 25°C; S62, add 0.1 parts of nattokinase and mix well; S63. Fill in sealed PE bags, evacuate to -0.09 MPa, and store at 4-15℃ away from light.

[0026] Comparative Example 1 The raw materials include 450 parts of corn flour, 250 parts of soybean meal, 50 parts of fish meal, 10 parts of monocalcium phosphate, and 5 parts of multivitamins; Preparation method: After mixing the raw materials, add water to adjust the moisture content to 60%, add 0.5% formic acid as a preservative, and store at room temperature.

[0027] Comparative Example 2 The raw materials include 400 parts of corn flour, 200 parts of soybean meal, 150 parts of wheat bran, and 2 parts of complex enzyme preparation; Preparation method: After mixing the raw materials, inoculate with non-psychrotrophic lactic acid bacteria, ferment at 15°C for 120 hours, and add 0.3% sodium benzoate for preservation.

[0028] Low temperature fermentation efficiency test verifies the fermentation efficiency of each embodiment and comparative example at a low temperature of 15°C: Examples 1 to 4 and Comparative Examples 1 to 2 were placed in a 15°C constant temperature fermentation tank, with 3 parallel samples set for each group. Samples were taken every 12 hours to detect the lactic acid content and pH value using HPLC. The time required for the pH to drop to 4.5 was recorded, and the electric meter recorded the heating power consumption to monitor energy consumption. A blank group with only the main raw material but no inoculation of bacteria was used as a reference. The time and unit energy consumption of each group to reach 3.5% lactic acid content were compared to evaluate the low-temperature fermentation efficiency. The experimental results are shown in Table 1. Figure 1 .

[0029] according to Figure 1 As can be seen, Example 1 completed fermentation within 72 hours, consuming only 18.5 kWh / ton, a 52% energy saving compared to Comparative Example 2, and achieved a starch conversion rate of 92.3%. Examples 2-4 were slightly inferior to Example 1 due to parameter fine-tuning, but still outperformed the comparative example. This demonstrates that the synergistic effects of magnetic field assistance, precise enzymatic hydrolysis, and psychrotrophic bacteria can overcome the bottleneck of low-temperature fermentation. Comparative Example 1, due to the lack of a fermentation process, had a lactic acid content of only 0.2%, indicating complete ineffectiveness.

[0030] Antibacterial effect and safety test: Escherichia coli O157 (10 5 CFU / g) and Aspergillus niger (10 4 Spores / g), samples were taken every 24 hours for plate count to detect the survival rate of miscellaneous bacteria, and formic acid / sodium benzoate residues in the comparative example were detected by HPLC and ICP-MS. The amount of iron ions dissolved in the nanoparticles was measured, and the acute toxicity was evaluated by gavage test in mice for 14 days. The experimental results are shown in Figure 2 .

[0031] The survival rate of miscellaneous bacteria in Examples 1-4 was ≤1.2%, and no preservative residue was detected, while 3200 ppm of residue was detected in Comparative Example 1 which relied on formic acid. The dissolved iron ions are far below the national standard limit, and the safety is up to standard. Although sodium benzoate is used for antibacterial treatment in Comparative Example 2, the mold survival rate still reaches 34.5%, which shows the limitations of chemical preservatives at low temperatures.

[0032] Comparison of nutritional indicators and feeding effects: The crude protein and amino acid composition of the final products of each group were analyzed using the Kjeldahl method and amino acid analyzer. 120 weaned piglets were randomly divided into 6 groups and fed for 14 days. Daily weight gain, feed-to-weight ratio and diarrhea rate were recorded. Ileal contents were collected for 16S rRNA sequencing to analyze the intestinal flora structure. The nutritional value and actual feeding effect were comprehensively evaluated. The experimental results are shown in Figure 3 .

[0033] Feeding trials showed that the daily weight gain of piglets in Example 1 was significantly higher than that in Comparative Example 2, with a 21.6% reduction in feed-to-weight ratio and a diarrhea rate of only 3.2%. Intestinal flora analysis showed that lactic acid bacteria accounted for 38.7% of the total in Example 1, three times higher than in Comparative Example 1, confirming that low-temperature fermented feed can improve intestinal health. While Example 3 achieved slightly better weight gain due to optimized enzymatic hydrolysis, Example 1 still achieved the best overall benefits.

[0034] Technical features not described in the present invention can be achieved through or by adopting existing technologies and will not be described in detail here. Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A low-temperature fermented liquid feed, characterized in that: The method comprises main raw materials, auxiliary raw materials, additives and bacterial strains, wherein the main raw materials include 380-420 parts of corn flour, 190-210 parts of soybean meal and 142-158 parts of wheat bran; Auxiliary raw materials include 95-108 parts of apple pomace, 70-80 parts of carrot pomace, and 70-80 parts of pumpkin pomace; Additives include 4.5-6 parts of cryoprotectant, composite mineral premix, enzyme preparation, 2.7-3.3 parts of chitosan microcapsule lysine, 0.045-0.055 parts of nanoparticles, 0.08-0.12 parts of nattokinase; The bacterial strains include 40-60 parts of cold-resistant lactic acid bacteria and 18-22 parts of yeast.

2. The low-temperature fermented liquid feed according to claim 1, characterized in that: The corn flour was crushed through a 60-mesh sieve, the soybean meal was crushed through a 40-mesh sieve, and the wheat bran was crushed through a 30-mesh sieve.

3. The low-temperature fermented liquid feed according to claim 1, characterized in that: The rotten part of the apple pomace is removed, the carrot pomace is peeled, and the pumpkin pomace is seeded, and then steamed at >100°C for 8-10 minutes to soften; The apple pomace, carrot pomace and pumpkin pomace are all crushed to a particle size of ≤3 mm.

4. The low-temperature fermented liquid feed according to claim 1, characterized in that The cryoprotectant is one or more of trehalose, sucrose fatty acid ester, hydroxyproline or polyglycerol fatty acid ester.

5. The low-temperature fermented liquid feed according to claim 1, characterized in that: The enzyme preparation comprises 0.9-1.1 parts of low-temperature α-amylase, 0.45-0.55 parts of neutral protease, 0.045-0.055 parts of pectinase, and 0.027-0.033 parts of cellulase.

6. The low-temperature fermented liquid feed according to claim 1, characterized in that: The particle size of the nanoparticles is 50 nm.

7. The low-temperature fermented liquid feed according to claim 1, characterized in that: The composite mineral premix comprises 2.9-3.5 parts of ferrous sulfate, 2.3-2.8 parts of zinc sulfate, 0.7-0.9 parts of copper sulfate, 1.4-1.7 parts of manganese sulfate and 1.8-2.2 parts of carrier medical stone powder.

8. A method for preparing a low-temperature fermented liquid feed according to claim 1, characterized in that: The following steps are involved: S1. Pretreatment of abandoned fruit tree residues Mix apple pomace, carrot pomace and pumpkin pomace and crush them; S2, enzymatic liquefaction Add pectinase and cellulase, adjust pH to acidic and stir; S3, main raw materials mixed conditioning S31, mixing corn flour, soybean meal, and wheat bran, adding composite mineral premix and low-temperature protective agent, and mixing for 15 minutes at a speed of 25 rpm; S32, adding pretreated fruit and vegetable residues and mixing; S4, low temperature enzymatic hydrolysis S41, adding low-temperature α-amylase and stirring; S42, add neutral protease and stir; S5. Inoculation and fermentation of cold-resistant bacteria S51 and lactic acid bacteria were cultured in MRS medium at 12-18°C for 24 h, and yeast was cultured in YPD medium at 25°C for 16-20 h with shaking at 120 rpm. S52, the activated bacteria are introduced into the material after the enzymatic hydrolysis in step S4, and chitosan microcapsule lysine and Nanoparticles; S53, pre-fermentation stage, temperature 25±1°C, 24 hours; The temperature of the main fermentation stage was 15±1℃ for 72 hours, and the pH was monitored to drop naturally below 4.5; S6. Termination of fermentation and post-processing S61. Raise the temperature of the fermented material in S52 to 60±1°C and hold for 10 minutes to inactivate the enzyme and bacteria, and immediately cool to below 25°C; S62, add nattokinase and mix well; S63. Fill in sealed PE bags, evacuate to -0.09 MPa, and store at 4-15℃ away from light.

9. The method for preparing low-temperature fermented liquid feed according to claim 8, characterized in that: In step S1, the apple pomace is removed of rotten parts, the carrot pomace is peeled, and the pumpkin pomace is deseeded, and then steamed at >100° C. for 8-10 minutes to soften them. The apple pomace, carrot pomace, and pumpkin pomace are mixed and processed by a hammer crusher to a particle size of ≤3 mm; After adding pectinase and cellulase in step S2, adjust the pH to 4.5 with citric acid and stir at 30 rpm in a constant temperature water bath at 35±1°C for 2 hours; In step S32, the mixer was started and purified water was slowly injected at a water-to-material ratio of 1.86:

1. 5% NaHCO3 solution was added by spraying and mixing was continued for 20 minutes until the pH reached 6.0±0.

2.

10. The method for preparing low-temperature fermented liquid feed according to claim 8, characterized in that: In step S41, low-temperature α-amylase is added, and the mixture is stirred at a constant temperature of 40±1°C for 1.5 hours at a speed of 50 rpm, until the iodine solution reacts to a reddish-brown color and the starch is completely degraded. In step S42, neutral protease is added, and the mixture is stirred at a constant temperature of 30±1°C for 1 hour at a speed of 30 rpm, until the free amino acid content is ≥2.5% as determined by the ninhydrin method; In step S52, The nanoparticles were ultrasonically dispersed in 5 parts of sterile water and simultaneously added to the material after enzymatic hydrolysis in step S4; In step S53 , a 0.3 T static magnetic field is applied to the periphery of the fermentation tank to assist in the main fermentation stage.

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