Bacterial preparation metagen of clostridium butyricum with high selenium-loading activity and application of bacterial preparation metagen

Abstract

The invention provides a bacterial preparation metagen of clostridium butyricum with high selenium-loading activity and application of the bacterial preparation metagen. The bacterial preparation metagen is prepared by inoculating clostridium butyricum with the preservation number of CGMCC No.30181 into a culture medium and carrying out fermentation culture. According to the present invention, the metagen is prepared from the fermentation broth of the clostridium butyricum with the high selenium loading effect, and the prepared metagen has the polypeptide with the antibacterial effect, and can promote the growth and development of meat ducks, improve the feed conversion rate, increase the oxidation resistance and the immunity, and improve the meat quality. The prepared composite biological preparation containing the metabiotics can effectively solve the problem of excessive addition of antibiotic products in current feed, and plays an important role in reducing drug residues of poultry products, reducing bacterial drug resistance and the like; in addition, the compound biological preparation contains selenium ions which are cooperated with prebiotics, so that a good biological intervention effect can be generated on poultry.

Description

Technical Field

[0001] The invention belongs to the technical field of biological products, and particularly relates to a bacterial preparation postbiotic of Clostridium butyricum with high selenium-carrying activity and application thereof. Background Art

[0002] With the rapid development of today's social economy, more and more farms are adding hormones or drugs to feed to make them grow faster in order to gain more benefits. However, improper use of hormones and drugs will destroy the stability of the immune system of poultry and livestock, reduce their immunity, and produce drug resistance and drug residues. Selenium not only supports animal growth and development, but also prevents myocardial degeneration and necrosis, participates in protein synthesis, maintains normal visual function, improves body immunity, improves its resistance to invasion by foreign pathogens, and reduces the occurrence of diseases. It can also be used to prevent cardiovascular diseases and diabetes, and remove free radicals in the body to achieve anti-aging effects.

[0003] Studies have shown that Clostridium butyricum, alone or in combination with other probiotics and prebiotics, can effectively treat diarrhea, enteritis and constipation caused by dysbiosis, promote vitamin E absorption, decompose bile acid, and improve antioxidant capacity. As a feed additive, Clostridium butyricum can produce antimicrobial peptides and small molecule organic acids to fight pathogenic bacteria in the animal digestive tract, maintain and regulate microbial balance, improve the immune function of animals, and produce digestive enzymes and vitamins to promote animal digestion and food intake and nutritional effects. Therefore, it can be widely used to replace antibiotics for chickens, pigs, cattle and other animals, promote animal growth, prevent and treat dysentery and diarrhea, prevent and treat liver disease, and improve the survival rate of newborn animals. Summary of the invention

[0004] The purpose of the present invention is to provide a Clostridium butyricum bacterial preparation postbiotic with high selenium-carrying activity and application thereof, and to use the postbiotic for preparing a poultry feed additive.

[0005] The present invention first provides a bacterial preparation postbiotic of Clostridium butyricum, which is prepared by inoculating Clostridium butyricum with a preservation number of CGMCC No. 30181 into a culture medium for fermentation and culture;

[0006] As a specific record of the embodiment, the culture medium has a composition ratio as follows: peptone 5-10 g / L, beef extract powder 5-10 g / L, sodium acetate 3 g / L, Se 4+ Concentration 40~400.0mg / L, pH 6.8~7.0±0.2.

[0007] As a preferred embodiment, the Se 4+ The concentration is 360.0mg / L.

[0008] The fermentation culture has a culture temperature of 37-38°C and a culture time of 24 hours.

[0009] Furthermore, the bacterial preparation postbiotics contain selenium ions, polypeptides, α-amylase, lipase, lactic acid, butyric acid, acetic acid and propionic acid;

[0010] As a specific record of the embodiment, the amino acid sequence of the polypeptide is LEEIEEE (SEQ ID NO: 1, molecular weight: 889.39), LTEEE (SEQ ID NO: 2, molecular weight: 619.27), TIVDDK (SEQ ID NO: 3, molecular weight: 689.36), SELEEE (SEQ ID NO: 4, molecular weight: 734.30), GVQGAAKMKEA (SEQ ID NO: 5, molecular weight: 1088.56), IIKELPTV (SEQ ID NO: 6, molecular weight: 911.60), ENFTPLEK (SEQ ID NO: 7, molecular weight: 976.49);

[0011] Furthermore, the polypeptides IIKELPTV (SEQ ID NO: 6) and ENFTPLEK (SEQ ID NO: 7) provided by the present invention are used to prepare antibacterial products.

[0012] In another aspect, the present invention provides a use of the bacterial preparation postbiotics as a feed additive.

[0013] The present invention also provides a poultry feed, wherein the bacterial preparation postbiotics are added.

[0014] The present invention prepares postbiotics from the fermentation broth of Clostridium butyricum with high selenium loading effect. The prepared postbiotics have polypeptides with antibacterial effect, and can promote the growth and development of meat ducks, improve feed conversion rate and improve meat quality, such as improving the fatty acid composition of meat ducks, the antioxidant performance of meat ducks and improving the immunity of meat ducks. The postbiotics prepared by the present invention effectively solve the problem of excessive addition of antibiotic products in current feeds, and also make significant contributions to reducing drug residues, reducing bacterial resistance and other aspects. In addition, if selenium and Clostridium butyricum work together, it can not only supplement the selenium demand of poultry and livestock bodies but also balance the intestinal microecology. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 : The diagram of the cumulative enrichment of selenium by Clostridium butyricum in liquid culture medium with different selenium contents. The control group was fermented in the above liquid culture medium without adding selenium, and the test group (addition amount 40-400 mg / L) was fermented by Clostridium butyricum in liquid culture medium containing different selenium contents.

[0016] Figure 2 :The inhibitory effect of Clostridium butyricum postbiotics on Escherichia coli before and after acclimation.

[0017] Figure 3 :The inhibitory effect of Clostridium butyricum postbiotics on Riemerella anatipestifer before and after domestication.

[0018] Figure 4 :The inhibitory effect of Clostridium butyricum postbiotics on Salmonella before and after acclimation.

[0019] Figure 5 , 6 , 7, 8: Flow cytometric plots of Escherichia coli, Riemerella anatipestifer, and Salmonella when the high-load selenobutyric acid Clostridium postbiotic was added at a ratio of 1:1.

[0020] Fig. 9 :Electron micrograph of the effect of high-load selenobutyric acid Clostridium postbiotics on the morphology of Escherichia coli.

[0021] Fig.10 :Electron micrograph of the effect of high-load selenobutyric acid Clostridium postbiotics on the morphology of Limerella.

[0022] Fig.11 :MS / MS spectrum and planar structure diagram of IIKELPTV sequence.

[0023] Fig.12 : Secondary mass spectrum and planar structure diagram of ENFTPLEK sequence.

[0024] Fig.13 :IIKELPTV sequence 3D structure diagram.

[0025] Fig.14 : ENFTPLEK sequence 3D structure diagram.

[0026] Fig.15 :Bar graph showing the effect of high selenium ion loading Clostridium butyricum on fatty acids in breast muscle of duck meat. DETAILED DESCRIPTION

[0027] The invention obtains high-load selenobutyric clostridium (with the deposit number of CGMCC No.30181), prepares a fermentation bacterial liquid with bactericidal and growth-promoting effects by optimizing fermentation conditions, and analyzes the components in the bacterial liquid.

[0028] The starting strain Clostridium butyricum used in the present invention contains high concentration of Se 4+ ions in the culture medium, and the strains rich in Se 4+ The strains screened were isolated under high Se 4+The strain was able to grow stably under high concentration conditions, which improved the ability of Clostridium butyricum to load high selenium; when the amount of selenium ions added to the culture medium was 360 mg / L, the selenium ion content in the bacteria could reach 21.30 μg / L. The Clostridium butyricum was deposited on March 28, 2024 at the General Microbiology Center of the China Microbiological Culture Collection Administration Committee, Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, with a deposit number of CGMCC No. 30181.

[0029] The culture medium used in the embodiment of the present invention has the following specific composition: 5-10 g / L peptone, 5-10 g / L beef extract powder, 3 g / L sodium acetate, 4+ The concentration is 40-400.0 mg / L, the pH value is 6.8-7.0±0.2, the culture temperature is 37-38°C, and the culture time is 24 hours.

[0030] The present invention is described in detail below with reference to specific embodiments and accompanying drawings.

[0031] Example 1: Cultivation and domestication of Clostridium butyricum with high selenium ion loading

[0032] The Se content in the culture medium was gradually increased. 4+ The butyric bacillus was domesticated in a concentration-controlled manner, and after continuous culture of the domesticated strains for several generations, the bacterial morphology, growth activity, and selenium content of the strain were compared with those of the butyric bacillus before domestication to further determine the characteristics of the butyric bacillus after domestication and to ensure that it can be stably propagated.

[0033] A strain that was domesticated and cultured can tolerate high concentrations of selenium ions (Se 4+ )(360mg / L) of Clostridium butyricum (CGMCC No.30181) strain was deposited at the General Microbiology Center of China Microbiological Culture Collection Committee, Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing on March 28, 2024, with the deposit number CGMCC No.30181. The domesticated selenium-rich Clostridium butyricum has the ability to load selenium ions. When the selenium ion addition amount is 360.0mg / L, the organic selenium content of the bacteria is 52.41μg / L (see Figure 1 ), which is greater than the selenium content of ordinary duck-derived Lactobacillus plantarum.

[0034] Example 2: Preparation of postbiotics and analysis of effective components of Clostridium butyricum before and after acclimation

[0035] 1) Preparation of postbiotics rich in small peptides: 200 μl of bacterial strains were inoculated into 100 ml of RCM medium, cultured at 37°C for 24 h under anaerobic conditions, and then centrifuged at 4°C, 6000 r / min for 10 min. The supernatant was taken and filtered through a bio-organic filter membrane to obtain postbiotics, which are rich in small peptides.

[0036] The culture medium used was composed of 5-10 g / L peptone, 5-10 g / L beef extract powder, 3 g / L sodium acetate, and 1 g / L Se 4+ Concentration 40~400.0mg / L, pH 6.8~7.0±0.2.

[0037] 2) Analysis of postbiotic components: The amylase content in the postbiotic of Clostridium butyricum after domestication was 0.22U / mL, which was 4.76% higher than that of the postbiotic prepared from Lactobacillus plantarum before domestication; the lipase content was 35.66U / L, which was 60.12% higher than that before domestication; the small peptide content was 20.98mg / mL, which was 12.25% higher than that before domestication; the acetic acid content was 0.107mg / mL, which was 16.30% higher than that before domestication; the butyric acid content was 0.762mg / mL, which was 14.93% higher than that before domestication; the isovaleric acid content was 0.119mg / mL, which was 10.92% higher than that before domestication; and the amino acid content was 563.98, which was 2.35% higher than that before domestication.

[0038] Example 3: Comparison of the antibacterial effect of postbiotics of Clostridium butyricum before and after acclimation

[0039] 1) Determination of the antibacterial curves of different postbiotics rich in small peptides

[0040] After high-load selenobutyric Clostridium (CGMCC No.30181) was cultured in RCM medium for 24 hours, postbiotics were extracted and mixed with the culture medium inoculated with harmful bacteria in a ratio of 1:3 and 1:1, and then placed in a microbial growth analyzer for growth curve determination.

[0041] Figure 2 , Figure 3 , Figure 4 The results showed that Clostridium butyricum had no inhibitory effect on harmful bacteria when the ratio of the added Clostridium butyricum to harmful bacteria was 1:3 before and after acclimation. Clostridium butyricum had a significant inhibitory effect on the growth and reproduction of Escherichia coli, Riemerella anatipestifer, and Salmonella when the ratio of the added Clostridium butyricum to harmful bacteria was 1:1 before and after acclimation. Figure 2 It showed that the Escherichia coli added with Clostridium butyricum postbiotics did not grow for 36 hours. Figure 3 It showed that Riemerella anatipestifer added with Clostridium butyricum postbiotics did not grow for 36 consecutive hours. Figure 4The results showed that the Salmonella with the addition of Clostridium butyricum postbiotics did not grow for 24 hours. The above test results showed that when the Clostridium butyricum postbiotics were added at a ratio of 1:1, it had a good inhibitory effect on harmful bacteria, and the antibacterial effect of the domesticated Clostridium butyricum (CGMCC No.30181) was enhanced.

[0042] 2) Determination of apoptosis rate of harmful bacteria when postbiotics rich in small peptides are added at a ratio of 1:1

[0043] The results in Table 2 show that high-load selenobutyric Clostridium (CGMCC No. 30181) can increase the apoptosis rate of Escherichia coli, Salmonella, Staphylococcus aureus, and Riemerella anatipestifer, which indicates that the antibacterial effect is enhanced after acclimation. Figures 5 to 8 It shows that after adding high-load selenobutyric Clostridium postbiotics, the number of dead bacteria increased, the cell apoptosis rate increased, and the antibacterial effect was obvious.

[0044] Table 1: Effect of high-load selenobutyric acid Clostridium postbiotics on the apoptosis rate of harmful bacteria

[0045]

[0046] 3) Changes in the morphology of harmful bacteria when the ratio of postbiotics rich in small peptides is 1:1

[0047] Depend on Fig. 9 Scanning electron microscopy showed that high load of Clostridium butyricum postbiotics destroyed the structure of E. coli, and the bacteria were obviously ruptured after adding postbiotics. Fig.10 It can be seen that the R. anatipestifer cells with high-load selenobutyric Clostridium postbiotics were significantly shrunken and ruptured, indicating that high-load selenobutyric Clostridium postbiotics can effectively inhibit the growth of Escherichia coli and R. anatipestifer.

[0048] Example 4: Sequence analysis and effect identification of small metabiotic peptides before and after acclimation of Clostridium butyricum

[0049] 1) Sequence analysis of small peptides in postbiotics

[0050] A commercial company was commissioned to perform protein shotgun identification and analysis on Clostridium butyricum and high-load selenobutyricum. The experimental method was to add an appropriate amount of 0.1% TFA to the sample, mix it, centrifuge it at 20,000g for 5 minutes, take the supernatant, transfer it to a 10KD ultrafiltration centrifuge tube, and centrifuge it at 12,000g for 15 minutes. Add 200μL 0.1% TFA and centrifuge it at 12,000g for 15 minutes, repeat twice, collect the filtrate, desalt it using C18StageTip, and dry it in vacuum. After drying, the peptides were re-dissolved with 0.1% FA, and the peptide concentration was determined for LC-MS analysis. An appropriate amount of peptides was taken from each sample and chromatographically separated using the nanoliter flow rate Easy nL C1200 chromatography system (Thermo Scientific). After the sample was injected into the Trap Column, it was gradient separated through the chromatographic analysis column at a flow rate of 300nl / min. After peptide separation, DDA (data dependent acquisition) mass spectrometry analysis was performed using a Q-Exactive HF-X mass spectrometer (Thermo Scientific). The search was performed using the mass spectrometry database retrieval software MaxQuant 2.4.14.0. After the fermentation broth of the strain was centrifuged, it was filtered through an organic filter membrane to make postbiotics. 0.1% TFA was added to the postbiotics, mixed, centrifuged at 20,000×g for 5 minutes, the supernatant was transferred to a 10KD ultrafiltration centrifuge tube, and centrifuged at 12,000×g for 15 minutes. 200 μL of 0.1% TFA was added, centrifuged at 12,000×g for 15 minutes, repeated twice, the filtrate was collected, desalted using a C18 StageTip, and vacuum dried. The dried peptides were re-dissolved with 0.1% FA and the peptide concentration was determined. An appropriate amount of peptides was taken for chromatographic separation using a nanoliter flow rate Easy nLC 1200 chromatography system (Thermo Scientific).

[0051] The main amino acid sequences measured were LEEIEEE, LTEEE, TIVDDK, SELEEE, GVQGAAKMKEA, IIKELPTV, and ENFTPLEK; among them, the unique amino acid sequences of high-load selenobutyric Clostridium were LEEIEEE, LTEEE, SELEEE, IIKELPTV, and ENFTPLEK.

[0052] Among them, the amino acid sequence secondary mass spectra and structure of IIKELPTV and ENFTPLEK, which are unique to high-load selenobutyric acid Clostridium postbiotics, are shown in Figure 2. Figure 11 to Figure 14 As shown in the literature, antimicrobial peptides generally have specific amino acids such as lysine, arginine, tryptophan and glycine. The peptides obtained from high-load selenobutyrate Clostridium postbiotics contain lysine. Based on the amino acid sequence, it is speculated that high-load selenobutyrate Clostridium postbiotics have higher antibacterial ability.

[0053] 2) Identification of the antibacterial effect of high-load selenobutyric acid Clostridium mixed peptides

[0054] The small peptides with amino acid sequences of IIKELPTV and ENFTPLEK were commissioned to a company for chemical synthesis, and the micropore dilution method was used to verify the antibacterial effect of the synthetic peptides on Escherichia coli, Salmonella and Riemerella anatipestifer. The culture medium without added bacteria was set as the negative control, the culture medium with added bacteria but no antimicrobial peptides was set as the positive control, and the culture medium with added antimicrobial peptides was set as the experimental group. The culture was cultured at 37℃ for 24 hours, the absorbance was measured at a wavelength of 600nm, and the inhibition rate was calculated.

[0055] Table 2: Inhibition rate of harmful bacteria by high-load selenobutyric acid Clostridium synthetic peptides

[0056]

[0057] From the results in Table 2, it can be seen that the screened small peptides have better antibacterial effects on Escherichia coli, Salmonella and Riemerella anatipestifer.

[0058] Example 5: Effect of high-load selenobutyric acid Clostridium postbiotics on the growth and development of broiler ducks

[0059] 180 healthy one-day-old Beijing ducks with similar body weight were selected and randomly divided into 5 groups, with 6 replicates in each group and 6 ducks in each replicate. The control group was fed with a basic diet, group I was fed with a basic diet + Clostridium butyricum fermentation broth, group II was fed with a basic diet + a high-load Clostridium selenobutyricum body group, group III was fed with a basic diet + a high-load Clostridium selenobutyricum postbiotics, and group IV was fed with a basic diet + a high-load Clostridium selenobutyricum fermentation broth group. The amount of probiotic preparation added to the experimental diet was 0.3%. The experimental design is shown in Table 3, and the basic diet composition is shown in Table 4. The feeding period was 42 days.

[0060] Table 3: Design table of meat duck breeding experiment

[0061]

[0062] Table 4: Basic feed composition for broiler ducks

[0063]

[0064] 1 The vitamin premix provides the following per kilogram of feed: VA1 2000 IU; VD3 2500 IU; VE 20 mg; VK3 3 mg; VB1 3 mg; VB2 8 mg; VB6 7 mg; D-pantothenic acid 20 mg; niacin 50 mg; folic acid 1.5 mg; biotin 0.1 mg. 2) The trace element premix provides the following per kilogram of feed: copper 9 mg; zinc 110 mg; iron 100 mg; manganese 100 mg; iodine 0.6 mg. 3) Metabolizable energy is a calculated value, and the others are measured values.

[0065] The results in Table 5 show that compared with the control group, the daily feed intake and feed-to-weight ratio of groups II, III and IV at 42 days of age was significantly reduced (P < 0.05), among which the feed-to-weight ratio of group I decreased by 3.11%, group II decreased by 10.12%, group III decreased by 10.89%, and group IV decreased by 12.45%, indicating that the high-load selenobutyric Clostridium postbiotics also have biological activity. Adding high-load selenobutyric Clostridium (CGMCC No. 30181) to the feed can reduce the feed-to-weight ratio, improve feed utilization, and enhance the digestion and absorption capacity of broiler ducks, thereby improving the growth performance of broiler ducks.

[0066] Table 5: Growth performance of 42-day-old broiler ducks

[0067]

[0068]

[0069] Example 6: Effect of high-load selenobutyric acid Clostridium postbiotics on slaughter performance of broiler ducks

[0070] The results in Table 6 show that compared with the control group, the slaughter rate and evisceration rate of Group II, Group III, and Group IV were significantly increased (P < 0.05). The breast muscle rate of Group I, Group II, Group III, and Group IV was significantly increased (P < 0.05). Among them, Group III had the best slaughter performance, with a slaughter rate increase of 4.20%, a evisceration rate increase of 5.62%, and a breast muscle rate increase of 39.46%, which indicates that high-load selenobutyric acid Clostridium postbiotics can effectively improve the slaughter performance of meat ducks.

[0071] Table 6: Slaughter performance of 42-day-old meat ducks

[0072]

[0073] Example 7: Effect of high-load selenobutyric acid Clostridium postbiotics on duck meat quality

[0074] As shown in Table 7, compared with the control group, the brightness (L*) of group I, group II, group III, and group IV was significantly reduced (P < 0.05); the redness (a*) of group II, group III, and group IV was significantly increased (P < 0.05); the cooking loss of group III was significantly reduced (P < 0.05). The cooking loss of group III was reduced by 28.30%. The lower the cooking loss, the better the water retention capacity of the muscle, which indicates that high-load selenobutyric acid Clostridium postbiotics can improve the meat color of meat ducks and effectively improve the water retention capacity of meat ducks.

[0075] Table 7: Meat quality of 42-day-old ducks

[0076]

[0077]

[0078] Example 8: Effect of high-load selenobutyric Clostridium postbiotics on fatty acid composition of meat ducks

[0079] From Table 8 and Fig.15 It can be seen that compared with the control group, the oleic acid (C18:1n9c) and monounsaturated fatty acid contents of groups Ⅰ, Ⅱ, Ⅲ, and Ⅳ increased, among which the contents of groups Ⅱ and Ⅳ increased significantly (P < 0.05); the saturated fatty acid content decreased, but not significantly. Unsaturated fatty acids are involved in the production of the rich aroma and flavor of duck meat, and are an important indicator for evaluating meat quality and nutritional value. The experiment showed that adding high-load selenobutyric acid Clostridium postbiotics to the feed can improve the fatty acid structure of meat ducks.

[0080] Table 8: Fatty acid composition of 42-day-old meat ducks

[0081]

[0082]

[0083] Example 9: Effect of high-load selenobutyric acid Clostridium postbiotics on antioxidant function of meat ducks

[0084] As shown in Table 9, compared with the control group, MDA in all experimental groups was significantly reduced (P < 0.05), GSH-PX in groups II and III was significantly increased (P < 0.05), T-SOD in all experimental groups was significantly increased (P < 0.05), among which group IV had the highest antioxidant capacity, indicating that high-load selenobutyric Clostridium butyricum has stronger antioxidant capacity than Clostridium butyricum.

[0085] Table 9: Antioxidant capacity of 42-day-old meat ducks

[0086]

[0087] Example 10: Effect of high load of selenobutyric Clostridium on immune performance of meat ducks

[0088] As shown in Table 10, compared with the control group, the amount of immunoglobulin in the experimental group increased, but not significantly (P>0.05).

[0089] Table 10: Immune performance of 42-day-old meat ducks

[0090]

[0091] In summary, the method of gradually increasing Se in the culture medium is adopted in the present invention. 4+The high-load selenobutyric Clostridium (CGMCC No.30181) obtained by concentration domestication screening not only has the probiotic advantages of Clostridium butyricum, but also has the ability to load high selenium ions, which can improve the selenium absorption rate, reduce the pollution of selenium ions to the environment and the toxic effects of selenium ions on organisms, and improve the ability of inorganic selenium to be converted into organic selenium in bacteria, greatly improving the utilization rate of selenium ions in poultry. At the same time, the high-load selenobutyric Clostridium domesticated and selected produces many postbiotics, including small peptides (antimicrobial peptides), small molecule organic acids, digestive enzymes, etc. Because it is rich in targeted antimicrobial peptides, it has a significant inhibitory effect on harmful bacteria such as Escherichia coli, Salmonella, and Riemerella anatipestifer. The digestive enzymes and other bioactive substances contained can promote the growth and development of poultry, enhance the meat quality of poultry products, and improve the antioxidant and immune capacity of poultry.

Claims

1. A postbiotic preparation of Clostridium butyricum, characterized in that: The postbiotics are prepared by inoculating Clostridium butyricum with a preservation number of CGMCC No. 30181 into a culture medium for fermentation culture.

2. The postbiotic according to claim 1, characterized in that The culture medium has the following composition: peptone 5-10 g / L, beef extract powder 5-10 g / L, sodium acetate 3 g / L, Se 4+ Concentration 40~400.0mg / L, pH 6.8~7.0±0.

2.

3. The postbiotic according to claim 2, characterized in that The Se 4+ The concentration is 360.0mg / L.

4. The postbiotic according to claim 1, characterized in that The fermentation culture has a culture temperature of 37-38°C and a culture time of 24 hours.

5. The postbiotic according to claim 1, characterized in that The postbiotics contain selenium ions, polypeptides, α-amylase, lipase, lactic acid, butyric acid, acetic acid and propionic acid.

6. The postbiotic according to claim 5, characterized in that The amino acid sequence of the polypeptide is SEQ ID NO: 1-7.

7. A polypeptide, characterized in that The amino acid sequence of the polypeptide is SEQ ID NO:6 or SEQ ID NO:

7.

8. Use of the polypeptide according to claim 7 in the preparation of antibacterial products.

9. Use of the postbiotics according to claim 1 as a feed additive.

10. A poultry feed, characterized in that: The poultry feed is added with the postbiotics according to claim 1 and / or the polypeptide according to claim 7.

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