A polypeptide composition for enhancing animal disease resistance and its preparation method

Abstract

This invention provides a polypeptide composition for enhancing animal disease resistance and its preparation method. The polypeptide composition, by weight, comprises the following components: 20-30 parts soybean meal polypeptide, 15-25 parts sea buckthorn seed meal polypeptide, 10-15 parts houttuynia cordata extract, 5-10 parts licorice extract, and 5-10 parts astragalus polysaccharide. The synergistic effect of the polypeptide and polysaccharide components in this invention can effectively enhance animal immunity, improve its resistance to external pathogens, and reduce the probability of infection.

Description

Technical Field

[0001] This invention relates to the field of animal husbandry technology, specifically to a polypeptide composition for improving animal disease resistance and its preparation method. Background Technology

[0002] With the continuous expansion of livestock farming, animals are more susceptible to pathogens such as bacteria, viruses, and parasites under intensive feeding and high environmental stress, leading to decreased immunity and increased disease incidence. In this situation, conventional disease control methods mainly rely on antibiotics and chemical drugs; however, the long-term use of these drugs has brought significant problems. Drug resistance: Due to the overuse of antibiotics, pathogenic strains gradually develop resistance, resulting in decreased drug sensitivity and the formation of "superbugs," posing a greater challenge to disease control. This resistance not only develops in animals but may also spread to humans through the food chain, threatening public health. Drug residues: Drug residues in livestock products caused by the long-term use of antibiotics pose a potential threat to human health. Excessive or inappropriate use of antibiotics can lead to excessive drug residues in meat, dairy, and egg products. Environmental pressure: Metabolites of antibiotics and chemical drugs in animals, as well as unabsorbed drug residues, are excreted in feces, entering the environment, polluting water and soil, and thus affecting ecosystems, especially aquatic organisms and soil microbial communities.

[0003] In light of the above issues, the animal husbandry industry is increasingly focusing on natural and green disease control solutions, seeking effective alternatives to antibiotics. In this regard, plant-derived extracts and bioactive peptides are gaining significant attention due to their natural safety and low toxicity. Plant peptides are typically extracted from plant proteins through specific enzymatic hydrolysis processes, preserving not only their biological activity but also possessing multiple functions such as enhancing immunity, anti-oxidation, and anti-inflammation. Furthermore, natural disease-fighting components such as astragalus polysaccharides, ganoderma lucidum polysaccharides, and green tea polyphenols have been proven to effectively enhance animals' disease resistance and reduce the frequency of disease occurrence due to their regulatory effects on the immune system.

[0004] Therefore, by combining plant peptides with natural disease-resistant extracts, a composition with both immunomodulatory and disease-resistant effects can be developed. This composition can not only replace some antibiotics, but also improve animal health and increase breeding efficiency, meeting the needs of antibiotic-free farming and sustainable development. Summary of the Invention

[0005] Based on the problems existing in the background technology, the present invention provides a polypeptide composition for improving the disease resistance of animals and a method for preparing the same.

[0006] This invention is implemented through the following technical solutions:

[0007] A polypeptide composition for enhancing animal disease resistance, comprising, by weight, the following components: 20-30 parts soybean meal polypeptide, 15-25 parts sea buckthorn seed meal polypeptide, 10-15 parts houttuynia cordata extract, 5-10 parts licorice extract, and 5-10 parts astragalus polysaccharide.

[0008] Furthermore, the preparation method of soybean meal peptides includes the following steps:

[0009] S101. Crush soybean meal and mix it with deionized water to obtain a suspension;

[0010] S102. Adjust the pH of the suspension to 8.0-9.0, extract at 45-50℃ for 2-3 hours, centrifuge to collect the supernatant after extraction, adjust the pH of the supernatant to 4.5-5.0 to precipitate the protein, collect the precipitate and wash it to neutral to obtain crude protein;

[0011] S103. Use protease to hydrolyze crude protein to obtain hydrolysate;

[0012] S104. The enzymatic hydrolysate is subjected to ultrafiltration, concentration, and drying to obtain soybean meal polypeptides.

[0013] Further, in step S103, the crude protein is enzymatically hydrolyzed using a protease. Specifically, the crude protein is dispersed in a buffer solution, and an alkaline protease is added at a concentration of 1%-2% of the crude protein mass. The pH is adjusted to 8.5-9.0, the temperature is maintained at 45-50℃, and the hydrolysis time is 1-2 hours. After hydrolysis, the temperature is heated to 85-90℃ and maintained for 10 minutes, then cooled to room temperature to obtain a preliminary hydrolysate. The pH of the preliminary hydrolysate is adjusted to neutral, and trypsin is added at a concentration of 0.5%-1% of the crude protein mass. The temperature is maintained at 45-50℃, and the hydrolysis time is 1-2 hours. After hydrolysis, the temperature is heated to 85-90℃ and maintained for 10 minutes, then cooled to room temperature to obtain the hydrolysate.

[0014] Soybean meal peptides have immunomodulatory and antioxidant effects, which can enhance the activity of immune cells and improve the immune function of animals. The abundant amino acids in soybean meal peptides help promote protein synthesis and improve the overall health of animals.

[0015] To obtain peptides with better immune-enhancing effects, this invention uses alkaline protease and trypsin in combination. First, alkaline protease is used for preliminary hydrolysis under alkaline conditions, followed by fine hydrolysis using trypsin under neutral conditions, generating various short-chain peptides and disease-fighting active ingredients. Through the combined action of alkaline protease and trypsin, soybean meal protein is gradually broken down into short-chain peptides, ultimately yielding mainly low-molecular-weight peptides, typically with a molecular weight between 500 and 2000 Daltons. These small-molecule peptides, due to their high solubility and bioavailability, are more easily absorbed by the animal intestines, contributing to improved disease resistance.

[0016] Furthermore, the preparation method of sea buckthorn seed meal polypeptide includes the following steps:

[0017] S201. After crushing the sea buckthorn seed meal, mix it with deionized water to obtain a suspension. Adjust the pH of the suspension to 12, extract at 37℃ for 50 min, repeat 2-3 times, and collect the supernatant by centrifugation.

[0018] S202. Adjust the pH of the supernatant to 5.0-5.5, add phytase and tanninase at 0.1-0.5% of the weight of sea buckthorn seed meal, hydrolyze at 35-50℃ for 2-5 hours, and after hydrolysis, heat to 85-90℃ and hold for 10 minutes to obtain the pretreated enzymatic hydrolysate.

[0019] S203. The pretreated enzymatic hydrolysate is enzymatically hydrolyzed using a protease to obtain the enzymatic hydrolysate;

[0020] S204. The enzymatic hydrolysate is subjected to ultrafiltration, concentration and drying to obtain sea buckthorn seed meal polypeptide.

[0021] Further, the specific operation of enzymatic hydrolysis of the pretreated enzymatic hydrolysate using protease in step S203 is as follows: add trypsin to the pretreated enzymatic hydrolysate, the amount of trypsin added is 1-2% of the mass of sea buckthorn seed meal, adjust the pH value to 8.0-8.5, maintain the temperature at 45-50℃, and the hydrolysis time is 1-2 hours. After hydrolysis, heat to 85-90℃, maintain for 10 minutes, and cool to room temperature to obtain the preliminary enzymatic hydrolysate; adjust the pH value of the preliminary enzymatic hydrolysate to neutral, add compound protease, the amount of compound protease added is 1-2% of the mass of sea buckthorn seed meal, maintain the temperature at 45-50℃, and the hydrolysis time is 1-2 hours. After hydrolysis, heat to 85-90℃, maintain for 10 minutes, and cool to room temperature to obtain the enzymatic hydrolysate.

[0022] Furthermore, the complex protease consists of flavor protease and neutral protease in a weight ratio of (1-2):1.

[0023] Sea buckthorn seed meal peptides are rich in vitamins and active ingredients, which can enhance animal immunity and anti-inflammatory capabilities, and reduce intracellular and extracellular oxidative stress. Furthermore, components of sea buckthorn seeds can promote intestinal health, improve digestion and absorption, and provide more effective nutritional support to the body. In this invention, trypsin is first used to act on large protein molecules, hydrolyzing their main peptide bonds and breaking them down into smaller peptide fragments. This effectively reduces the molecular weight of the protein, making it easier for subsequent complex proteases to act on the remaining peptide chains, further breaking them down into smaller peptide molecules. The combination of flavor proteases and neutral proteases can act on different peptide bonds, improving enzymatic hydrolysis efficiency and increasing the diversity and specificity of peptide types, thereby obtaining more comprehensive physiological activities. The peptides obtained after multi-step enzymatic hydrolysis are abundant and have a small molecular weight. These peptides exhibit excellent antioxidant properties in vivo, helping to scavenge free radicals and reduce oxidative damage. This peptide composition can effectively regulate the animal's immune system, improve the activity of antibodies and immune cells, and enhance disease resistance, making it particularly suitable as a functional additive in feed to promote animal health.

[0024] Furthermore, the specific preparation method of Houttuynia cordata extract is as follows: after washing and drying, Houttuynia cordata is pulverized. Using ethanol as the extraction solvent, Houttuynia cordata powder and ethanol are placed in a Soxhlet extractor at a weight ratio of 1:(8-12). The mixture is heated under reflux at a temperature of 40-50℃ for 40-60 minutes. The extraction is repeated 2-3 times. The extracts are combined and concentrated. Finally, the mixture is dried in a dryer at a temperature of 50-60℃ to obtain Houttuynia cordata extract.

[0025] Houttuynia cordata extract possesses natural antibacterial, antiviral, and anti-inflammatory properties, effectively inhibiting various pathogenic microorganisms. Its unique components can activate the immune system, promote the proliferation of immune cells, and increase animals' resistance to infection.

[0026] Furthermore, the specific preparation method of licorice extract is as follows: after washing and drying, licorice is pulverized, and 40-60% ethanol aqueous solution is used as the extraction solution. The licorice powder and ethanol aqueous solution are placed in a Soxhlet extractor at a weight ratio of 1:(12-16), heated to reflux, and the extraction temperature is 40-60℃. Under the condition of ultrasonic power of 75-85W, the extraction time is 40-60min, and the extraction is repeated 2-3 times. The extracts are combined and concentrated, and finally placed in a dryer to dry at a drying temperature of 50-60℃ to obtain licorice extract.

[0027] Licorice extract contains glycyrrhizic acid and flavonoids, which have immunomodulatory, anti-inflammatory, and antiviral effects, helping to alleviate inflammatory responses and enhance the animal's resistance. At the same time, the analgesic and antioxidant properties of licorice extract also contribute to improving the overall health of animals.

[0028] Astragalus polysaccharides are an important immune enhancer with significant immunomodulatory effects. They can increase the activity of macrophages and lymphocytes, boost antibody production, and strengthen the animal's immune system. Astragalus polysaccharides also possess antiviral and antibacterial properties, enhancing animals' resistance to pathogens in the environment.

[0029] The present invention also discloses a method for preparing a polypeptide composition that enhances the disease resistance of animals, comprising the following steps: mixing soybean meal polypeptide, sea buckthorn seed meal polypeptide, houttuynia cordata extract, licorice extract and astragalus polysaccharide evenly to obtain a polypeptide composition that enhances the disease resistance of animals.

[0030] Finally, this invention discloses the application of polypeptide compositions that enhance animal disease resistance as feed additives, with the addition amount accounting for 0.1-5% of the total feed.

[0031] The beneficial effects of this invention are:

[0032] The synergistic effect of peptides and polysaccharides in the composition of this invention can effectively enhance animal immunity, improve its resistance to external pathogens, and reduce the chance of infection. The sea buckthorn seed meal peptides, licorice extract, and houttuynia cordata extract in this composition all have antioxidant and anti-inflammatory effects, helping to reduce cell damage caused by oxidative stress, reduce inflammatory responses, and maintain cell health. Soybean meal peptides and sea buckthorn seed meal peptides can help improve the intestinal microenvironment, enhance intestinal absorption of nutrients, and improve feed utilization, thereby promoting animal growth and development. The combined action of licorice extract, houttuynia cordata extract, and astragalus polysaccharides can effectively resist common pathogenic bacteria and viral infections, further enhancing the animal's disease resistance and reducing the risk of disease transmission. Detailed Implementation

[0033] The technical solution of the present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0034] The alkaline protease, trypsin, flavor protease, and neutral protease used in the embodiments and comparative examples of this application were all purchased from Shanghai Yuanye Biotechnology Co., Ltd.; Astragalus polysaccharide was purchased from Shaanxi Bolin Biotechnology Co., Ltd.

[0035] Example 1

[0036] A polypeptide composition for enhancing animal disease resistance, comprising, by weight, the following components: 25 parts soybean meal polypeptide, 20 parts sea buckthorn seed meal polypeptide, 13 parts houttuynia cordata extract, 8 parts licorice extract, and 8 parts astragalus polysaccharide.

[0037] The preparation method of the composition includes the following steps: mixing soybean meal peptides, sea buckthorn seed meal peptides, houttuynia cordata extract, licorice extract and astragalus polysaccharide evenly to obtain a peptide composition that enhances the disease resistance of animals.

[0038] The preparation method of soybean meal peptides includes the following steps:

[0039] S101. Crush soybean meal and mix it with deionized water to obtain a 15% concentration suspension;

[0040] S102. Adjust the pH of the suspension to 9.0, extract at 45℃ for 3 hours, centrifuge and collect the supernatant after extraction, adjust the pH of the supernatant to 4.5 to precipitate the protein, collect the precipitate and wash until neutral to obtain crude protein;

[0041] S103. Enzymatic hydrolysis of crude protein using protease: Disperse crude protein in buffer solution, add alkaline protease at a concentration of 1.5% of crude protein mass, adjust pH to 8.5, maintain temperature at 45℃, hydrolyze for 2 hours, after hydrolysis, heat to 90℃, maintain for 10 minutes, cool to room temperature to obtain preliminary hydrolysate; adjust pH of preliminary hydrolysate to neutral, add trypsin at a concentration of 1% of crude protein mass, maintain temperature at 45℃, hydrolyze for 2 hours, after hydrolysis, heat to 90℃, maintain for 10 minutes, cool to room temperature to obtain hydrolysate;

[0042] S104. The enzymatic hydrolysate is subjected to ultrafiltration, concentration, and drying to obtain soybean meal polypeptides.

[0043] The preparation method of sea buckthorn seed meal polypeptide includes the following steps:

[0044] S201. After crushing the sea buckthorn seed meal, mix it with deionized water to obtain a 15% concentration suspension. Adjust the pH of the suspension to 12, extract at 37℃ for 50 min, repeat 3 times, and collect the supernatant by centrifugation.

[0045] S202. Adjust the pH of the supernatant to 5.5, add phytase and tanninase at 0.3% of the mass of sea buckthorn seed meal, hydrolyze at 40℃ for 4 hours, and heat to 90℃ after hydrolysis and maintain for 10 minutes to obtain pretreated enzymatic hydrolysate;

[0046] S203. Enzymatic hydrolysis of the pretreated hydrolysate using protease: Add trypsin to the pretreated hydrolysate at 2% of the sea buckthorn seed meal mass, adjust the pH to 8.5, maintain the temperature at 50℃, and hydrolyze for 2 hours. After hydrolysis, heat to 90℃ and maintain for 10 minutes, then cool to room temperature to obtain the preliminary hydrolysate. Adjust the pH of the preliminary hydrolysate to neutral, add a complex protease, which consists of flavor protease and neutral protease in a weight ratio of 2:1. The amount of the complex protease added is 1.5% of the sea buckthorn seed meal mass, maintain the temperature at 45℃, and hydrolyze for 2 hours. After hydrolysis, heat to 85-90℃ and maintain for 10 minutes, then cool to room temperature to obtain the hydrolysate.

[0047] S204. The enzymatic hydrolysate is subjected to ultrafiltration, concentration and drying to obtain sea buckthorn seed meal polypeptide.

[0048] The specific preparation method of Houttuynia cordata extract is as follows: after washing and drying, Houttuynia cordata is pulverized. Using ethanol as the extraction solvent, Houttuynia cordata powder and ethanol are placed in a Soxhlet extractor at a weight ratio of 1:10. The mixture is heated under reflux at a temperature of 45°C for 50 minutes. The extraction is repeated 3 times. The extracts are combined and concentrated. Finally, the mixture is dried in a dryer at a temperature of 55°C to obtain Houttuynia cordata extract.

[0049] The specific preparation method of licorice extract is as follows: After washing and drying, licorice is pulverized. Using 50% ethanol aqueous solution as the extraction solution, licorice powder and ethanol aqueous solution are placed in a Soxhlet extractor at a weight ratio of 1:14. The mixture is heated to reflux at a temperature of 55℃ and extracted for 80 minutes under ultrasonic power of 80W. The extraction is repeated 3 times. The extracts are combined and concentrated, and finally dried in a dryer at a drying temperature of 55℃ to obtain licorice extract.

[0050] Specifically, for the process of extracting heat while maintaining a constant temperature, multiple types of sensors are used to acquire heating data, and the heating process is intelligently controlled based on this data.

[0051] Construct a heating model for the heat-insulating extraction container and obtain current heating data;

[0052] Based on historical data of container heating, the heating model of the heat preservation and extraction container is trained to obtain the trained heating model of the heat preservation and extraction container.

[0053] During the current extraction process, based on the current heating data, the heating unit is controlled using the trained heat preservation extraction container heating model to keep the container temperature stable.

[0054] Preferably, the heating history data or current heating data includes at least the temperature of key points on the container. Gas flow rate Gas valve opening Volume of liquid in the container and container pressure etc.; Based on this, an input dataset is generated. Each item represents the heating data collected at that moment, for example... This represents the temperature at the critical point of the container at time 0. Gas flow rate Gas valve opening Volume of liquid in the container and container pressure wait;

[0055] Based on deep learning technology, a heating model for the heat preservation extraction container is constructed using a recurrent neural network (RNN). The above-mentioned input dataset is used as the input sequence data of the RNN, and the output sequence data of the hidden layer and the output layer are determined based on the activation function.

[0056] A heating model for the heat preservation extraction container was trained based on historical heating data; the loss function of the neural network was...

[0057]

[0058] in, for Predicted temperature at any given time; for The true temperature at any given moment.

[0059] The heating unit is controlled based on the trained insulated extraction container heating model, which better ensures the stability of the container temperature as the liquid gradually decreases during the extraction process, ensuring that the liquid properties do not change during the extraction process and improving the stability of the overall preparation process.

[0060] Example 2

[0061] A polypeptide composition for enhancing animal disease resistance, comprising, by weight, the following components: 30 parts soybean meal polypeptide, 20 parts sea buckthorn seed meal polypeptide, 13 parts houttuynia cordata extract, 8 parts licorice extract, and 8 parts astragalus polysaccharide.

[0062] The preparation methods of the composition and each component are the same as in Example 1.

[0063] Example 3

[0064] A polypeptide composition for enhancing animal disease resistance, comprising, by weight, the following components: 20 parts soybean meal polypeptide, 20 parts sea buckthorn seed meal polypeptide, 13 parts houttuynia cordata extract, 8 parts licorice extract, and 8 parts astragalus polysaccharide.

[0065] The preparation methods of the composition and each component are the same as in Example 1.

[0066] Example 4

[0067] A polypeptide composition for enhancing animal disease resistance, comprising, by weight, the following components: 25 parts soybean meal polypeptide, 15 parts sea buckthorn seed meal polypeptide, 13 parts houttuynia cordata extract, 8 parts licorice extract, and 8 parts astragalus polysaccharide.

[0068] The preparation methods of the composition and each component are the same as in Example 1.

[0069] Example 5

[0070] A polypeptide composition for enhancing animal disease resistance, comprising, by weight, the following components: 25 parts soybean meal polypeptide, 25 parts sea buckthorn seed meal polypeptide, 13 parts houttuynia cordata extract, 8 parts licorice extract, and 8 parts astragalus polysaccharide.

[0071] The preparation methods of the composition and each component are the same as in Example 1.

[0072] Comparative Example 1

[0073] A polypeptide composition, by weight, comprises the following components: 25 parts soybean meal polypeptide, 20 parts sea buckthorn seed meal polypeptide, 13 parts houttuynia cordata extract and 8 parts licorice extract.

[0074] The preparation methods of the composition and each component are the same as in Example 1.

[0075] Comparative Example 2

[0076] A polypeptide composition, by weight, comprises the following components: 45 parts soybean meal polypeptide, 13 parts houttuynia cordata extract, 8 parts licorice extract and 8 parts astragalus polysaccharide.

[0077] The preparation methods of the composition and each component are the same as in Example 1.

[0078] Comparative Example 3

[0079] A polypeptide composition, by weight, comprises the following components: 40 parts of sea buckthorn seed meal polypeptide, 13 parts of houttuynia cordata extract, 8 parts of licorice extract and 8 parts of astragalus polysaccharide.

[0080] The preparation methods of the composition and each component are the same as in Example 1.

[0081] Comparative Example 4

[0082] A polypeptide composition, by weight, comprises the following components: 25 parts soybean meal polypeptide, 20 parts sea buckthorn seed meal polypeptide, 13 parts houttuynia cordata extract, 8 parts licorice extract and 8 parts astragalus polysaccharide.

[0083] In the preparation method of soybean meal peptides, S103 involves dispersing crude protein in a buffer solution, adding alkaline protease at a concentration of 1.5% of the crude protein mass, adjusting the pH to 8.5, maintaining the temperature at 45°C, and hydrolyzing for 2 hours. After hydrolysis, the solution is heated to 90°C, maintained for 10 minutes, and then cooled to room temperature to obtain the enzymatic hydrolysate. The remaining preparation steps are the same as in Example 1. That is, a single alkaline protease is used to hydrolyze the crude protein to prepare soybean meal peptides.

[0084] The preparation methods of the composition and the remaining components are the same as in Example 1.

[0085] Comparative Example 5

[0086] A polypeptide composition, by weight, comprises the following components: 25 parts soybean meal polypeptide, 20 parts sea buckthorn seed meal polypeptide, 13 parts houttuynia cordata extract, 8 parts licorice extract and 8 parts astragalus polysaccharide.

[0087] In the preparation method S203 of sea buckthorn seed meal polypeptide, the pretreated enzymatic hydrolysate is hydrolyzed by protease: trypsin is added to the pretreated enzymatic hydrolysate at 2% of the mass of sea buckthorn seed meal, the pH is adjusted to 8.5, the temperature is maintained at 50℃, the hydrolysis time is 2h, after hydrolysis is completed, the temperature is heated to 90℃ and maintained for 10min, and then cooled to room temperature to obtain the enzymatic hydrolysate; the remaining preparation steps are the same as in Example 1; that is, sea buckthorn seed meal polypeptide is prepared by using a single trypsin to hydrolyze the pretreated enzymatic hydrolysate.

[0088] The preparation methods of the composition and the remaining components are the same as in Example 1.

[0089] Experimental Example 1

[0090] The polypeptide compositions from Examples 1-5 and Comparative Examples 1-5 were used as additives in the feed of laying hens; the addition amount was 2%.

[0091] Healthy 25-day-old laying hens that had not been vaccinated with any vaccines were randomly divided into 10 treatment groups and 1 control group (fed laying hen feed without the peptide composition). Each group consisted of 100 hens. Each treatment group was fed with the peptide compositions of Examples 1-5 and Comparative Examples 1-5 as additives in the laying hen feed, and was fed twice a day under the same conditions.

[0092] Starting at 80 days of age, the number of sick and dead chickens in each group was recorded daily until the end of the experiment. Sick chickens are a general term encompassing all diseases.

[0093] From 120 days to 220 days of age, the number of eggs laid and broken eggs in each group were recorded daily, with a total of 100 days for statistical analysis. Egg production rate (%) = Total egg production during the statistical period / (Number of laying hens in the pen × Number of statistical days) × 100%; Broken egg rate (%) = Total broken eggs during the statistical period / (Total egg production during the statistical period × Number of statistical days) × 100%.

[0094] The experimental results are shown in Table 1.

[0095] Table 1

[0096]

[0097] As can be seen from Table 1, the morbidity rate, broken egg rate, and egg production rate of the laying hens in Examples 1-5 were all better than those in the control group and Comparative Examples 1-5. This indicates that the polypeptide composition used in this invention, when added to the feed of laying hens as a feed additive, can improve the disease resistance of laying hens, enhance nutrient absorption, and strengthen the immunity of laying hens, thereby increasing the egg production rate and reducing the broken egg rate.

[0098] Experimental Example 2

[0099] The polypeptide compositions from Example 1 and Comparative Examples 1-5 were used as additives in broiler feed; the addition amount was 2%.

[0100] Healthy broilers aged 7 days without any vaccinations, provided by an egg farm, were randomly divided into 6 treatment groups and 1 control group (fed broiler feed without the added peptide composition), with 50 birds in each group. Each treatment group was fed the peptide composition corresponding to Example 1 and Comparative Examples 1-5 as an additive in their broiler feed, twice daily, with all other conditions being the same. Blood samples were collected from the jugular vein on days 14, 21, and 29 of the experiment, serum was separated, and Newcastle disease antibodies were detected.

[0101] The experimental results are shown in Table 2.

[0102] Table 2

[0103]

[0104] As can be seen from the results in Table 2, the polypeptide composition of Example 1 of the present invention can effectively increase the Newcastle disease antibody titer in broilers through the synergistic effect of each active ingredient, thereby enhancing the immune function and antiviral ability of broilers.

[0105] Finally, it should be noted that the above embodiments are merely illustrative of several implementations of the present invention and are not intended to limit the scope of the invention. For those skilled in the art, any modifications, equivalent substitutions, or improvements made without departing from the concept of the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A polypeptide composition for enhancing disease resistance in animals, characterized in that, By weight, it consists of the following raw materials: 20-30 parts soybean meal peptides, 15-25 parts sea buckthorn seed meal peptides, 13 parts houttuynia cordata extract, 8 parts licorice extract and 8 parts astragalus polysaccharide. The preparation method of the soybean meal polypeptide includes the following steps: S101. Crush soybean meal and mix it with deionized water to obtain a suspension; S102. Adjust the pH of the suspension to 8.0-9.0, extract at 45-50℃ for 2-3 hours, centrifuge to collect the supernatant after extraction, adjust the pH of the supernatant to 4.5-5.0 to precipitate the protein, collect the precipitate and wash it to neutral to obtain crude protein; S103. Use protease to hydrolyze crude protein to obtain hydrolysate; S104. The enzymatic hydrolysate is subjected to ultrafiltration, concentration, and drying to obtain soybean meal polypeptides; In step S103, the crude protein is enzymatically hydrolyzed using a protease. Specifically, the crude protein is dispersed in a buffer solution, and an alkaline protease is added at a concentration of 1%-2% of the crude protein mass. The pH is adjusted to 8.5-9.0, the temperature is maintained at 45-50℃, and the hydrolysis time is 1-2 hours. After hydrolysis, the temperature is heated to 85-90℃ and maintained for 10 minutes. The solution is then cooled to room temperature to obtain a preliminary hydrolysate. The pH of the preliminary hydrolysate is adjusted to neutral, and trypsin is added at a concentration of 0.5%-1% of the crude protein mass. The temperature is maintained at 45-50℃, and the hydrolysis time is 1-2 hours. After hydrolysis, the temperature is heated to 85-90℃ and maintained for 10 minutes. The solution is then cooled to room temperature to obtain the hydrolysate. The preparation method of the sea buckthorn seed meal polypeptide includes the following steps: S201. After crushing the sea buckthorn seed meal, mix it with deionized water to obtain a suspension. Adjust the pH of the suspension to 12, extract at 37℃ for 50 min, repeat 2-3 times, and collect the supernatant by centrifugation. S202. Adjust the pH of the supernatant to 5.0-5.5, add phytase and tanninase at 0.1-0.5% of the weight of sea buckthorn seed meal, hydrolyze at 35-50℃ for 2-5 hours, and after hydrolysis, heat to 85-90℃ and hold for 10 minutes to obtain the pretreated enzymatic hydrolysate. S203. The pretreated enzymatic hydrolysate is enzymatically hydrolyzed using a protease to obtain the enzymatic hydrolysate; S204. The enzymatic hydrolysate is subjected to ultrafiltration, concentration and drying to obtain sea buckthorn seed meal polypeptide; The specific operation of enzymatic hydrolysis of the pretreated enzymatic hydrolysate in step S203 is as follows: trypsin is added to the pretreated enzymatic hydrolysate at an amount of 1-2% of the sea buckthorn seed meal mass. The pH is adjusted to 8.0-8.5, the temperature is maintained at 45-50℃, and the hydrolysis time is 1-2 hours. After hydrolysis, the temperature is heated to 85-90℃ and maintained for 10 minutes. The solution is then cooled to room temperature to obtain the preliminary enzymatic hydrolysate. The pH of the preliminary enzymatic hydrolysate is adjusted to neutral, and a complex protease, which is a combination of flavor protease and neutral protease, is added at an amount of 1-2% of the sea buckthorn seed meal mass. The temperature is maintained at 45-50℃, and the hydrolysis time is 1-2 hours. After hydrolysis, the temperature is heated to 85-90℃ and maintained for 10 minutes. The solution is then cooled to room temperature to obtain the enzymatic hydrolysate. The preparation method of the houttuynia cordata extract is as follows: after washing and drying, houttuynia cordata is pulverized. Using ethanol as the extraction solvent, houttuynia cordata powder and ethanol are placed in a Soxhlet extractor at a weight ratio of 1:(8-12). The mixture is heated to reflux at a temperature of 40-50℃ for 40-60 minutes. The extraction is repeated 2-3 times. The extracts are combined and concentrated. Finally, the mixture is placed in a dryer and dried at a temperature of 50-60℃ to obtain the houttuynia cordata extract. The specific preparation method of the licorice extract is as follows: after washing and drying, licorice is pulverized. A 40-60% ethanol aqueous solution is used as the extraction solution. The licorice powder and the ethanol aqueous solution are placed in a Soxhlet extractor at a weight ratio of 1:(12-16). The mixture is heated to reflux at a temperature of 40-60℃ and extracted for 40-60 minutes under an ultrasonic power of 75-85W. The extraction is repeated 2-3 times. The extracts are combined and concentrated. Finally, the mixture is dried in a dryer at a temperature of 50-60℃ to obtain the licorice extract.

2. The polypeptide composition for enhancing animal disease resistance according to claim 1, characterized in that, The weight ratio of the flavor protease to the neutral protease is (1-2):

1.

3. A method for preparing a polypeptide composition for improving animal disease resistance as described in any one of claims 1-2, characterized in that, Includes the following steps: The polypeptide composition for improving animal disease resistance is obtained by mixing soybean meal polypeptide, sea buckthorn seed meal polypeptide, houttuynia cordata extract, licorice extract and astragalus polysaccharide evenly.

4. The application of a polypeptide composition for enhancing animal disease resistance as described in any one of claims 1-2 as a feed additive in the preparation of animal feed, characterized in that, The amount added should be 0.1-5% of the total feed.

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