A kind of Bacillus ceti, postbiotics of Bacillus ceti and its preparation method and application

Abstract

The present invention relates to the technical field of feed additives, and discloses a Bacillus soberoni, a Bacillus soberoni postbiotic, and a preparation method and application thereof, Bacillus soberoni WT-1, and its preservation number is: CGMCC No. 29651. Bacillus soberoni postbiotics are prepared by inactivating Bacillus soberoni. Preparation method of Bacillus soberoni postbiotics: after activating Bacillus soberoni WT-1, a seed liquid is obtained; the seed liquid is inoculated in a fermentation medium for culturing to obtain a fermentation product; the fermentation product is inactivated to obtain the Bacillus soberoni postbiotics. Application of the Bacillus soberoni or Bacillus soberoni postbiotics in preparing feed. It shows that the use of Bacillus soberoni WT-1 postbiotics will not interfere with the homeostasis of its intestinal flora, and will not have an adverse effect on the water environment. At the same time, when the addition amount is 0.4% to 0.6%, the Bacillus soberoni postbiotics can significantly improve the growth health and anti-infection ability of aquatic animals.

Description

Technical Field

[0001] The present invention belongs to the technical field of feed additives, and particularly relates to Cetobacterium somerae, postbiotics of Cetobacterium somerae, and their preparation methods and applications. Background Art

[0002] With the continuous improvement of the living standards of the people in our country, the demand for aquatic products has been continuously expanding, and the aquaculture industry has become one of the important pillar industries in the agricultural economy. The scale of traditional aquaculture models is small and the output is limited, making it difficult to meet people's demand for aquatic products. High-density intensive aquaculture can, to a certain extent, increase the aquaculture output and meet this demand. However, intensive aquaculture increases the risk of disease infection in farmed animals and may also cause pollution to the aquaculture environment, thus having an adverse impact on the green and sustainable development of aquaculture.

[0003] In aquaculture, in order to reduce the occurrence of diseases, a certain dose of antibiotics is usually used. However, in addition to killing pathogenic bacteria in the aquaculture water body, this measure may also disrupt the intestinal microbial balance of aquatic animals, affect their immune systems, and ultimately may lead to more serious losses. In addition, the long-term use of antibiotics may also cause some pathogenic bacteria to develop drug resistance, and the antibiotic residues in aquatic animals also directly threaten human health and safety. The use of antibiotics has now been regulated, so finding safe, effective, and green alternatives to antibiotics has become the focus of continuous attention of aquaculture researchers.

[0004] Postbiotics refer to preparations of inanimate microorganisms and / or their components that are beneficial to the health of the host. Compared with probiotics, postbiotics have higher safety and stability and can avoid potential risks such as the spread of drug resistance genes that may be brought about by the transfer of live bacteria. Therefore, postbiotics are considered an ideal way to replace antibiotics and have become a hot topic in the current research field of microecological preparations. As a probiotic preparation containing inactivated microorganisms, the main methods for inactivating bacteria include heat treatment, ultraviolet irradiation, high-pressure treatment, enzyme treatment, and ultrasonic treatment. After cell inactivation and lysis, extraction and purification techniques such as centrifugation, dialysis, freeze-drying, and column chromatography can also be used to complete the preparation of postbiotics. The main active components of postbiotics can be divided into two parts: bacterial cell components and bacterial metabolites. Among them, the bacterial components mainly include peptidoglycan, lipoteichoic acid, etc., while the bacterial metabolites mainly include exopolysaccharides, short-chain fatty acids, etc.

[0005] As a genus of the family Fusobacteriaceae, Cetobacterium exists in many fish species and has a relatively high abundance in intestinal microorganisms, being the dominant genus in the intestines of many freshwater fish. Finegold first isolated and identified Cetobacterium somerae from the feces of autistic children ( Cetobacterium somerae). In 2008, Tsuchiya successively isolated 17 strains of Cetobacterium somerae from the intestines or feces of freshwater fish, and experiments proved that these Cetobacterium somerae all had the ability to produce acetic acid and vitamin B 12 . More and more studies have shown that Cetobacterium somerae is the main symbiotic bacterium in the intestines of various fish, especially freshwater fish.

[0006] Currently, the postbiotics products that can be used in aquaculture disclosed mainly come from lactic acid bacteria or Saccharomyces cerevisiae. However, most of these bacteria are isolated from the food or plants ingested by higher mammals, and their metabolites or the bacteria themselves will affect the stability of the intestinal flora in aquatic animals. SUMMARY OF THE INVENTION

[0007] The present invention provides a Cetobacterium somerae, a postbiotic of Cetobacterium somerae, and its preparation method and application, solving the problem that the postbiotics products used in aquaculture in the prior art mainly come from lactic acid bacteria or Saccharomyces cerevisiae. However, most of these bacteria are isolated from the food or plants ingested by higher mammals, and their metabolites or the bacteria themselves will affect the stability of the intestinal flora in aquatic animals.

[0008] Cetobacterium somerae ( Cetobacterium somerae ) WT-1, with the preservation number: CGMCC No. 29651.

[0009] The second object of the present invention is to protect a postbiotic of Cetobacterium somerae, which is obtained by inactivating the above-mentioned Cetobacterium somerae.

[0010] The third object of the present invention is to protect the preparation method of the above-mentioned postbiotic of Cetobacterium somerae, which specifically includes the following steps:

[0011] After activating Cetobacterium somerae WT-1, a seed solution is obtained; the seed solution is inoculated into a fermentation medium for cultivation to obtain a fermentation product; the fermentation product is inactivated to obtain the postbiotic of Cetobacterium somerae.

[0012] Preferably, the inactivation conditions are inactivation at 70°C - 75°C for 30 min - 40 min.

[0013] Preferably, the fermentation medium is a modified GAM anaerobic medium.

[0014] Preferably, the fermentation culture conditions are: under anaerobic environment, 28°C - 29°C, 10 h - 12 h.

[0015] Preferably, the inoculation amount of the seed solution is 5% - 6% by volume.

[0016] The fourth object of the present invention is to protect the application of the above-mentioned Cetobacterium somerae or the postbiotic of Cetobacterium somerae in the preparation of feed.

[0017] Preferably, the feed is used to protect the intestinal health of freshwater fish and improve the body's immunity.

[0018] Preferably, the feed consists of a basal feed and Cetobacterium somerae, or consists of a basal feed and postbiotics of Cetobacterium somerae.

[0019] By weight, the basal feed is composed of the following raw materials: 35 to 37 parts of fish meal, 14.6 to 15.6 parts of soybean meal, 6 to 8 parts of wheat gluten, 11.95 to 13.95 parts of wheat flour, 1 to 3 parts of brewer's yeast, 2.2 to 4.2 parts of peanut meal, 8 to 10 parts of corn protein powder, 6 to 8 parts of fish oil, 1.5 to 3.5 parts of soy lecithin, 0.5 part of vitamin premix, 1 part of mineral premix, 0.1 part of choline chloride, 0.1 part of calcium propionate, 0.05 part of ethoxyquinoline, 0.5 part of sodium alginate, 0.5 part of calcium dihydrogen phosphate, and 1 part of attractant.

[0020] The Cetobacterium somerae or postbiotics of Cetobacterium somerae is 0.4 to 0.6 parts.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] (1) The postbiotic product developed in the present invention uses Cetobacterium somerae WT-1 isolated from the intestinal tract of aquatic animals, and the bacteria have been inactivated, without the safety risk of using live bacteria, which is conducive to industrial development and utilization. The experimental results show that adding a small amount of Cetobacterium somerae or postbiotics of Cetobacterium somerae to the feed can significantly improve the growth health and anti-infection ability of farmed turbot, and its effect mainly comes from inactivated bacteria and their metabolites.

[0023] (2) The postbiotics of Cetobacterium somerae WT-1 developed in the present invention uses Cetobacterium somerae WT-1 isolated from aquatic animals, and its safety has been widely identified. At the same time, its presence can also be detected in the water environment, indicating that using the postbiotics of Cetobacterium somerae WT-1 will not interfere with the intestinal flora homeostasis and will not have an adverse impact on the water environment; and when the addition amount is 0.4% - 0.6%, the postbiotics of Cetobacterium somerae can significantly improve the growth health and anti-infection ability of aquatic animals.

[0024] (3) Biological material preservation information

[0025] Biological material preservation information Cetobacterium somerae ( Cetobacterium somerae ) WT-1 was deposited at the General Microbiological Center of the China Committee for Culture Collection of Microorganisms on January 11, 2024, with the deposit number: CGMCC No. 29651, and the deposit address is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. Description of the drawings

[0026] Figure 1 Effects of postbiotics of Cetobacterium somerae on the activities of intestinal lipase and trypsin in turbot; A: Effects on lipase activity; B: Effects on trypsin activity.

[0027] Figure 2 Effects of postbiotics of Cetobacterium somerae on the intestinal tissue structure of turbot; A: Intestinal structure of turbot after different treatments; B: Intestinal villus height; C: Lamina propria; D: Muscular layer thickness.

[0028] Figure 3 Effects of postbiotics of Cetobacterium somerae on the relative expression levels of intestinal tight junction protein genes; A: Relative expression level of tight junction protein Claudin-1 gene; B: Relative expression level of tight junction protein ZO-1 gene; C: Relative expression level of tight junction protein Tricellulin gene; D: Relative expression level of tight junction protein Occludin gene.

[0029] Figure 4 Effects of postbiotics of Cetobacterium somerae on the relative expression levels of intestinal inflammatory factor genes; A: IL-1β Relative expression level of the gene; B: TNF-α Relative expression level of the gene; C: IL-8 Relative expression level of the gene; D: IL-10 Relative expression level of the gene.

[0030] Figure 5Effect of postbiotics of Cetobacterium somerae on the intestinal flora composition of turbot; A is the relative abundance map at the phylum level; among them, Acinetobacter is the genus Acinetobacter, Pseudomonas_E is the genus Pseudomonas-E, Acetilactobacillus is the genus Acetilactobacillus, Lactobacillus is the genus Lactobacillus, Ralstonia is the genus Ralstonia, Niallia is the genus Niallia, Streptococcus is the genus Streptococcus, Staphylococcus is the genus Staphylococcus, Pseudonocardia is the genus Pseudonocardia, Citrobacter A is the genus Citrobacter-A, Others is others; B is the relative abundance map at the genus level, among which, Proteobacteria is the phylum Proteobacteria, Firmicutes_D is the phylum Firmicutes-D, Actinobacteriota is the phylum Actinobacteriota, Bacteroidota is the phylum Bacteroidota, Firmicutes_A is the phylum Firmicutes-A, Planctomycetota is the phylum Planctomycetota, Gemmatimonadota is the phylum Gemmatimonadota, Firmicutes_C is the phylum Firmicutes-C, Fusobacteriota is the phylum Fusobacteriota, Synergistota is the phylum Synergistota, Others is others; C is the relative abundance of the phylum Proteobacteria; D is the relative abundance map of the phylum Firmicutes.

[0031] Figure 6 Effect of postbiotics of Cetobacterium somerae on the relative expression levels of inflammatory factor genes in the kidneys of turbot; A: HIF-1 α Relative expression level of genes; B: IL-1β Relative expression level of genes; C: TNF-α Relative expression level of the gene; D: LYZ Relative expression level of genes.

[0032] Figure 7 Effect of postbiotics of Cetobacterium somerae on the survival rate of turbot after intestinal infection with pathogenic bacteria. Specific embodiments

[0033] Next, specific embodiments of the present invention will be combined to clearly and completely describe the technical solutions in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0034] In the methods described in the embodiments of the present invention, unless otherwise specified, they are all conventional methods. The materials, reagents, etc. used, unless otherwise specified, can all be obtained from commercial channels.

[0035] The improved Gifu anaerobic medium used in the present invention, namely the improved GAM anaerobic medium, is derived from HB8518 of Qingdao Hope Bio-Technology Co., Ltd.

[0036] Example 1

[0037] 1. Strain screening and postbiotic acquisition

[0038] Cetobacterium somerae was isolated from the intestine of wild-type zebrafish. First, the zebrafish was anesthetized and dissected in a laminar flow hood, and its intestine was taken out and placed in a centrifuge tube containing sterile phosphate buffer solution with a concentration of 0.01 M. Then, 3 sterile small steel beads with a diameter of 2 mm were added to break the sample, and a homogenate was prepared after the breaking was completed. The homogenate was evenly spread on the solid plate of the improved GAM anaerobic medium, and the plate was placed in an anaerobic incubator at 28 °C for 12 hours. Subsequently, through further purification of single colonies and liquid scale-up culture, finally, by sequencing and sequence alignment on NCBI, i.e., https: / / www.ncbi.nlm.nih.gov / , Cetobacterium somerae was screened and preserved in the China General Microbiological Culture Collection Center with the preservation number of CGMCC No. 29651.

[0039] The preparation process of the postbiotic is as follows: Before preparing the feed, Cetobacterium somerae was activated. The single colony was added to 15 mL of the improved GAM anaerobic medium and cultured overnight for 12 h. Then, the activated Cetobacterium somerae bacterial solution was added to 500 mL of the improved GAM anaerobic medium at a volume ratio of 5% and cultured for 12 hours. After that, it was heated to 70 °C in a water bath and maintained for 30 minutes to inactivate the live bacteria of Cetobacterium somerae. Through verification on the GAM plate with a part of the culture solution, it was found that there were no surviving strains, and the postbiotic of Cetobacterium somerae was prepared. The concentration of the postbiotic of Cetobacterium somerae is 7×10 7 CFU / mL. It was stored at -4 °C and immediately used for feed preparation.

[0040] 2. Feed preparation

[0041] According to the nutritional requirements of turbot, the present invention uses fish meal, soybean meal, wheat gluten, wheat flour, brewer's yeast, peanut meal, and corn protein powder as the main protein sources; and fish oil and soybean lecithin as the main fat sources. The feed consists of a basal diet and postbiotics of Cetobacterium somerae; by weight, the basal diet is composed of the following raw materials: 35 parts of fish meal, 14.6 parts of soybean meal, 6 parts of wheat gluten, 11.95 parts of wheat flour, 1 part of brewer's yeast, 2.2 parts of peanut meal, 8 parts of corn protein powder, 6 parts of fish oil, 1.5 parts of soybean lecithin, 0.5 part of vitamin premix, 1 part of mineral premix, 0.1 part of choline chloride, 0.1 part of calcium propionate, 0.05 part of ethoxyquinoline, 0.5 part of sodium alginate, 0.5 part of calcium dihydrogen phosphate, and 1 part of attractant.

[0042] Postbiotics of Cetobacterium somerae were added to the basal diet at 0 g / kg, 4 g / kg, and 6 g / kg respectively to prepare three isonitrogenous and isolipidic diets, among which, crude protein: 48 g / 100 g, crude fat: 12 g / 100 g, and they were named Ctrl, that is, adding 0 g / kg of postbiotics of Cetobacterium somerae; F-4, that is, adding 4 g / kg of postbiotics of Cetobacterium somerae; F-6, that is, adding 6 g / kg of postbiotics of Cetobacterium somerae. The specific feed formulas are shown in Table 1.

[0043] Table 1 Feed formulas of different groups (g / kg)

[0044]

[0045] Note: a Purchased from Segreen Bioengineering Co., Ltd. b Vitamin premix, based on the addition amount per kg of feed: vitamin A, 32 mg; vitamin E, 240 mg; vitamin K, 10 mg; ascorbic acid, 120 mg; vitamin B12, 10 mg; vitamin H, 60 mg; choline dihydrogen citrate, 7000 mg; folic acid, 20 mg; inositol, 800 mg; niacin, 20 mg; D-calcium pantothenate, 60 mg; vitamin B6, 20 mg; riboflavin, 45 mg; vitamin B1, 25 mg.

[0046] c Mineral premix, based on the addition amount per kg of feed: CuSO 4 ·5H 2 O, 10 mg; FeSO 4 ·7H 2 O, 80 mg; ZnSO 4 ·H 2 O, 50 mg; MnSO 4 ·H 2 O, 45 mg; MgSO 4 ·7H 2O, 1200 mg; CoCl 2 ·, 5 mg; Na 2 SeO 3 , 20 mg; calcium iodate, 60 mg.

[0047] d Attractant, based on the addition amount per kg of feed: betaine, 4 g; dimethyl-β-propiothetin, 2 g; glycine, 2 g; alanine, 1; inosine 5'-phosphate, 1 g.

[0048] Crush the formula amounts of fish meal, soybean meal, wheat gluten, wheat flour, brewer's yeast, peanut meal, and corn protein powder, and filter through a 60-mesh sieve; after mixing evenly, add the formula amounts of fish oil and soy lecithin, vitamin premix, mineral premix, choline chloride, calcium propionate, ethoxyquinoline, sodium alginate, calcium dihydrogen phosphate, and attractant, and knead to ensure full mixing of the raw materials and avoid oil caking. After mixing, put it into a mixer and mix evenly for 15 minutes to obtain the mixed raw materials; then add water and the formula amount of postbiotics of Cetobacterium somerae to the mixed raw materials to obtain the feed; among them, the ratio of the mixed raw materials to water is 1 kg: 200 mL. Make the feed into feed pellets with a diameter of 3 mm through a granulator. Place the made feed pellets in an oven at 55 °C for 12 hours, then seal and package, and store in a -20 °C refrigerator for later use.

[0049] 3. Breeding experiment

[0050] The experiment was carried out in the indoor flowing water breeding system of Longhui Aquatic Products Co., Ltd. in Weihai City, Shandong Province. Before the formal experiment, the turbot was temporarily raised in the breeding pond for 2 weeks and fed with the control group feed, i.e., Ctrl, to make it gradually adapt. After the temporary raising ended, all turbot were fasted for 24 hours, and turbot with uniform size, no obvious damage on the body surface, and an initial weight of 10.48 ± 0.03 g were selected and randomly assigned to 18 200-L breeding barrels, with 40 turbot in each barrel. The 18 breeding barrels were randomly divided into 6 treatment groups, with 3 replicates in each treatment group.

[0051] During the breeding process, the water temperature was maintained at 16 °C - 18 °C, the salinity was maintained at 27‰ - 29‰, the dissolved oxygen was 7 mg / L, the concentrations of ammonia nitrogen and nitrite were both less than 0.1 mg / L, and the pH value was maintained at 7.3 - 7.9. Feed to satiation twice a day at 7 am and 7 pm. Change the water 2 hours after each feeding, and clean the residual bait and feces. The entire breeding cycle was 8 weeks.

[0052] After the breeding experiment ended, all turbot were fasted for 24 hours and then sampled. Before sampling, the turbot were anesthetized with 20 mg / L tricaine, and the remaining quantity and weight in each bucket were recorded. Four fish were randomly selected from each bucket for dissection, and the liver, intestine, and kidney were taken and placed in 2 mL centrifuge tubes. After being quickly frozen in liquid nitrogen, they were transferred to an -80°C refrigerator for storage for subsequent molecular experiments. In addition, the intestines of four fish were selected from each bucket and fixed with Bouin's fixative, and then replaced with 75% alcohol for storage after 24 hours for subsequent intestinal section analysis.

[0053] Experimental results

[0054] (1)Growth indexes

[0055] Table 2 Growth data

[0056]

[0057] All data are expressed as mean ± standard error. Values with different superscript letters in the same row are significantly different, P <0.05.

[0058] As shown in Table 2, compared with the control group, that is, Ctrl, supplementing 4 g / kg probiotics, that is, F-4, or 6 g / kg probiotics, that is, F-6, in the feed can significantly improve the weight gain rate, specific growth rate, feed efficiency, and protein retention rate of turbot.

[0059] (2)Lipase activity detection

[0060] Figure 1 To investigate the effects of probiotics of Cetobacterium somerae on the activities of intestinal lipase and trypsin in turbot. As Figure 1 shown, compared with the control group, supplementing 4 g / kg probiotics or 6 g / kg probiotics in the feed can significantly increase the lipase activity of turbot, as shown in Figure 1 A; and the trypsin activity, as shown in Figure 1 B. **** p <0.0001.

[0061] (3)Intestinal health detection

[0062] Figure 2 To investigate the effects of probiotics of Cetobacterium somerae on the intestinal tissue structure of turbot. Figure 2 A in p <0.0001. It indicates that probiotics can significantly improve the intestinal structure of turbot.

[0063] As Figure 2As shown in A of Figure 2 , compared with the control group, supplementing 4 g / kg or 6 g / kg of postbiotics in the feed can significantly improve the intestinal structure of turbot, specifically manifested as a significant increase in intestinal villus height, see Figure 2 of B; the lamina propria is significantly reduced, see Figure 2 of C; the muscular layer thickness is significantly increased, see

[0064] Figure 3 Effect of postbiotics of Cetobacterium somerae on the relative expression levels of intestinal tight junction protein genes in turbot. * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001, ns, no significant difference.

[0065] As Figure 3 shown, compared with the control group, supplementing 4 g / kg or 6 g / kg of postbiotics in the feed can significantly increase the relative expression levels of tight junction proteins Tricellulin and Occludin genes in the intestine of turbot, see Figure 3 of C and D. At the same time, supplementing 4 g / kg of postbiotics in the feed can significantly increase the relative expression levels of tight junction proteins Claudin-1 and ZO-1 genes; supplementing 6 g / kg of postbiotics in the feed has a relatively small increase in the relative expression levels of tight junction proteins Claudin-1 and ZO-1 genes, see Figure 3 of A and B.

[0066] Figure 4 Effect of postbiotics of Cetobacterium somerae on the relative expression levels of intestinal inflammatory factor genes in turbot. * p < 0.05, ** p < 0.01, ns, no significant difference.

[0067] As Figure 4 shown, compared with the control group, supplementing 4 g / kg or 6 g / kg of postbiotics in the feed can significantly reduce the relative expression levels of pro-inflammatory cytokine IL-1β genes in the intestine of turbot, see Figure 4 of A; IL-8 relative expression levels of genes, see Figure 4 of C; and TNF-α relative expression levels of genes, see Figure 4 of B; at the same time, supplementing 4 g / kg of postbiotics in the feed can significantly increase the relative expression levels of anti-inflammatory cytokine IL-10 genes, see Figure 4 of D.

[0068] Figure 5 Effect of postbiotics of Cetobacterium somerae on the intestinal flora composition of turbot; * p <0.05, ** p <0.01. Figure 5 A is the abundance map of the intestinal flora composition at the phylum level, Figure 5 B is the abundance map of the intestinal flora composition at the genus level.

[0069] As Figure 5 shown, compared with the control group, supplementing 4 g / kg or 6 g / kg of postbiotics in the diet can significantly improve the intestinal flora composition of turbot, specifically manifested in a significant decrease in the relative abundance of the potentially harmful phylum Proteobacteria, see Figure 5 C; at the same time, it significantly increases the relative abundance of the potentially beneficial phylum Firmicutes, see Figure 5 B and D.

[0070] (4)Detection of body immunity

[0071] Figure 6 Effect of postbiotics of Cetobacterium somerae on the relative expression levels of inflammatory factor genes in the kidneys of turbot; * p <0.05, ** p <0.01, *** p <0.001, ns, no significant difference.

[0072] As Figure 6 shown, compared with the control group, supplementing 4 g / kg or 6 g / kg of postbiotics in the diet can significantly increase the relative expression levels of immune genes HIF-1α genes in the kidneys, see Figure 6 A, and LYZ the relative expression level of the gene, see Figure 6 D; at the same time, supplementing 4 g / kg of postbiotics in the diet can significantly increase the relative expression level of the pro-inflammatory cytokine IL-1β gene, see Figure 6 B; and TNF-α the relative expression level of the gene, see Figure 6 C.

[0073] Figure 7 Effect of postbiotics of Cetobacterium somerae on the survival rate of turbot after intestinal infection with pathogenic bacteria, ** p <0.01, *** p <0.001.

[0074] As Figure 7 shown, compared with the control group, supplementing 4 g / kg or 6 g / kg of postbiotics in the diet can significantly increase the survival rate of turbot infected with Edwardsiella tarda. The survival rate of the control group was 25.00%, and the survival rates of the F-4 and F-6 groups were 66.67% and 79.17%, respectively.

[0075] Although the preferred embodiments of the present invention have been described, additional changes and modifications can be made by those skilled in the art once they learn the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present invention.

[0076] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. An application of a postbiotic of Cephalosporin in preparing feed, characterized in that: The Cetobacterium somerae ) The postbiotics are prepared by inactivating Bacillus sordellii; the accession number of the Bacillus sordellii is: CGMCC No. 29651; The feed is used to protect the intestinal health of freshwater fish and improve the body's immunity; The feed is composed of a basic feed and Bacillus thuringiensis postbiotics; In the feed, the added amount of Bacillus sordellii postbiotics is 4g / kg or 6g / kg.

2. The use of the postbiotics of Bacillus sordellii in preparing feed according to claim 1, characterized in that: The specific preparation process of the Bacillus sordellii postbiotics is as follows: After activating the Bacillus sorcerii, a seed solution is obtained; inoculating the seed liquid into a fermentation medium for culturing to obtain a fermentation product; The fermentation product is inactivated to obtain the Bacillus sordellii postbiotics.

3. The use of the postbiotics of Bacillus sordellii in preparing feed according to claim 2, characterized in that: The inactivation condition is 70° C. to 75° C. for 30 min to 40 min.

4. The use of the postbiotic of Cephalosporin Bacillus thuringiensis in preparing feed according to claim 2, characterized in that: The fermentation medium is a modified GAM anaerobic medium.

5. The use of the postbiotics of Cephalosporin Bacillus thuringiensis in preparing feed according to claim 2, characterized in that: The fermentation culture conditions are: in an anaerobic environment, the temperature is 28°C to 29°C, and the time is 10h to 12h.

6. The use of the postbiotics of Cephalosporin Bacillus thuringiensis in preparing feed according to claim 2, characterized in that: The inoculation amount of the seed liquid accounts for 5% to 6% of the volume of the fermentation medium.

7. The use of the postbiotic of Cephalosporin Bacillus thuringiensis in preparing feed according to claim 1, characterized in that: The basic feed is composed of the following raw materials by weight: 35 to 37 parts of fish meal, 14.6 to 15.6 parts of soybean meal, 6 to 8 parts of gluten, 11.95 to 13.95 parts of wheat flour, 1 to 3 parts of brewer's yeast, 2.2 to 4.2 parts of peanut meal, 8 to 10 parts of corn protein meal, 6 to 8 parts of fish oil, 1.5 to 3.5 parts of soybean lecithin, 0.5 parts of vitamin premix, 1 part of mineral premix, 0.1 parts of choline chloride, 0.1 parts of calcium propionate, 0.05 parts of ethoxyquin, 0.5 parts of sodium alginate, 0.5 parts of calcium dihydrogen phosphate, and 1 part of attractant.

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