Bacillus coagulans and application thereof

Abstract

The invention discloses bacillus coagulans and application thereof, and belongs to the technical field of microorganisms. The bacillus coagulans is preserved in the China Center for Type Culture Collection (CCTCC), the preservation number of the bacillus coagulans is CCTCC NO: M 20251025, and the bacillus coagulans is classified and named as bacillus coagulans WH20. According to the invention, a strain of bacillus coagulans WH20 is separated for the first time, and the strain WH20 can effectively relieve the inflammatory response of aquatic animals after being infected by oxygen deficiency and / or spring viraemia of carp virus (SVCV) and remarkably improve the survival rate of the aquatic animals after being infected by oxygen deficiency and / or spring viraemia of carp virus (SVCV), so that the bacillus coagulans WH20 can be used for preventing and treating the aquatic animals after being infected by oxygen deficiency and / or spring viraemia of carp virus (SVCV). The compound can be developed as a medicine and / or a feed additive for improving the hypoxia resistance and the aquatic virus infection resistance of aquatic animals, and plays an important role in aquaculture.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and particularly relates to a Bacillus coagulans strain and application thereof. Background Art

[0002] Hypoxia refers to a process in which the body's available oxygen cannot meet its needs due to changes in the external environment, leading to metabolic abnormalities and a series of changes in tissue function and morphological structure. Hypoxia exacerbates oxidative stress in tissue cells, causing irreversible damage to the body. Dissolved oxygen (DO) is one of the key factors limiting water quality in intensive aquatic animal farming systems. The complex and volatile water environment makes farmed fish highly susceptible to hypoxia during breeding and transportation, and in severe cases, it can lead to mass fish mortality.

[0003] Spring carp viremia (SVC) is an acute, highly lethal infectious disease caused by the spring carp viremia virus (SVCV). It has been listed as a notifiable disease by the World Organization for Animal Health and is a Category II animal disease designated by my country's Ministry of Agriculture and Rural Affairs. The main pathological symptoms of affected fish include bleeding in the liver, spleen, and kidneys, severe peritonitis, and hemorrhagic enteritis. Each year, approximately 10 hatchery farms nationwide test positive for SVCV. Among the positive samples detected, 70.7% were common carp, 12.0% were koi, 8.0% were goldfish, 5.2% were crucian carp, 1.8% were grass carp, 1.4% were silver carp, 0.2% were bighead carp, and 0.7% were other species.

[0004] Bacillus coagulans was first isolated from a sample of spoiled milk in 1915 and is considered a promising probiotic candidate. In 2007, the European Union Food Safety Authority (EFSA) declared it safe, listing it as Generally Recognized as Safe (GRAS) and Qualified Presumption of Safety (QPS). In 2004, the Ministry of Agriculture issued Announcement No. 372, approving its use as a feed additive. It is now widely used in the livestock, aquaculture, and pharmaceutical industries. Bacillus coagulans is a non-pathogenic, facultatively anaerobic, Gram-positive bacterium that produces spores and L-lactic acid by breaking down sugars. It possesses characteristics of both lactic acid bacteria and bifidobacteria, as well as strong stress tolerance, such as acid and bile salt tolerance, and the ability to grow in low-oxygen environments. It also produces compounds that have health benefits. Research has shown that Bacillus coagulans is heat-resistant, with an optimal growth temperature of 35–50°C and an optimum pH of 5.5–6.5. These properties suggest its great potential as a probiotic. Its activity remains unchanged after treatment at 60°C for 90 minutes within a pH range of 4.0–8.0. Furthermore, the activity of this strain is unaffected by esterases, amylases, and organic solvents, demonstrating excellent stability and tolerance. Therefore, Bacillus coagulans has broad potential for application in aquatic animal disease prevention and control, as well as in the growth of aquatic animals. However, studies on Bacillus coagulans's ability to tolerate hypoxia and viral infections in aquatic animals have yet to be reported. Summary of the Invention

[0005] The present invention aims to provide a strain of Bacillus coagulans and its use. The present invention isolated a strain of Bacillus coagulans for the first time, which can effectively alleviate the inflammatory response of aquatic animals after hypoxia and / or infection with spring carp viremia virus (SVCV), and significantly improve the survival rate of aquatic animals after hypoxia and / or infection with spring carp viremia virus (SVCV).

[0006] In a first aspect, the present invention provides a strain of Bacillus coagulans ( Bacillus coagulans )WH20, Bacillus coagulans ( Bacillus coagulans ) The accession number of WH20 is CCTCC NO:M 20251025.

[0007] The strain WH20 was isolated from the intestines of crucian carp from Wuhan, Hubei Province. 16S rDNA sequencing of the strain WH20 was performed, and its 16S rDNA sequence was subjected to BLAST multiple sequence alignment at NCBI (https: / / www.ncbi.nlm.nih.gov / ), and a phylogenetic tree was constructed. The results showed that the strain WH20 had a high degree of homology with Bacillus coagulans and was in the same branch as Bacillus coagulans strain MTCC5260. Based on the above identification results, the strain WH20 was named Bacillus coagulans ( Bacillus coagulans )WH20.

[0008] In a second aspect, the present invention provides a biological bacterial agent, comprising the above-mentioned Bacillus coagulans ( Bacillus coagulans )WH20.

[0009] In some embodiments, the biological inoculant is a liquid inoculant.

[0010] In some embodiments, the liquid inoculum contains Bacillus coagulans ( Bacillus coagulans )WH20 content ≥1×10 8 cfu / mL.

[0011] In a third aspect, the present invention provides a method for preparing the above-mentioned biological agent, comprising the following steps: Bacillus coagulans ) WH20 is inoculated into a liquid culture medium for cultivation, and the resulting culture is separated and resuspended in a solvent to obtain a biological agent.

[0012] In a fourth aspect, the present invention provides the Bacillus coagulans ( Bacillus coagulans ) Use of WH20, any of the above-mentioned biological agents, or the biological agents obtained by the above-mentioned preparation methods in at least one of the following: A1) preparing drugs and / or feed additives for improving the hypoxia tolerance of aquatic animals; A2) preparing drugs and / or feed additives for improving the resistance of aquatic animals to aquatic viral infections.

[0013] In some embodiments, in A1), improving the hypoxia tolerance of aquatic animals includes at least one of inhibiting the inflammatory response caused by hypoxia in aquatic animals, improving the survival rate of aquatic animals after hypoxia, and reducing organ damage caused by hypoxia in aquatic animals.

[0014] In some embodiments, in A2), improving the ability of aquatic animals to resist aquatic virus infection includes at least one of inhibiting the inflammatory response caused by aquatic animals infected with aquatic viruses, improving the survival rate of aquatic animals infected with aquatic viruses, and reducing organ damage caused by aquatic animals infected with aquatic viruses.

[0015] In some embodiments, the aquatic virus comprises a carp spring viremia virus.

[0016] In some embodiments, the organ includes at least one of the brain and the intestine.

[0017] The beneficial effects of the present invention are as follows: Different from the prior art, the present invention is the first to isolate a strain of Bacillus coagulans ( Bacillus coagulans ) WH20, the strain WH20 can effectively alleviate the inflammatory response of aquatic animals after hypoxia and / or infection with spring carp viremia virus (SVCV), and significantly improve the survival rate of aquatic animals after hypoxia and / or infection with spring carp viremia virus (SVCV). Therefore, it can be developed as a drug and / or feed additive to improve the tolerance of aquatic animals to hypoxia and the ability to resist aquatic viral infection, and play an important role in aquaculture. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The survival rate results of bighead carp after hypoxia stress after gavage with different bacterial agents in Example 1 of the present invention; Figure 2 This is the phylogenetic tree result of strain WH20 constructed in Example 1 of the present invention; Figure 3 The survival rate results of zebrafish subjected to hypoxia stress by oral administration of Bacillus coagulans WH20 in Example 2 of the present invention; Figure 4 The results of hypoxia treatment of zebrafish using oral administration of Bacillus coagulans WH20 and H&E staining of the intestine and brain in Example 2 of the present invention are as follows; Figure 5 The results of Example 2 of the present invention are as follows: zebrafish were treated with hypoxia by oral administration of Bacillus coagulans WH20 and their intestines and brains were collected for inflammatory factor detection; Figure 6 The survival rate of zebrafish infected with SVCV after oral administration of Bacillus coagulans WH20 in Example 3 of the present invention; Figure 7 The results of Example 3 of the present invention are as follows: zebrafish were orally inoculated with Bacillus coagulans WH20, then infected with SVCV, and their hearts, spleens, livers, intestines, kidneys, and brains were collected for inflammatory factor detection; Figure 8 These are the results of H&E staining of the liver, brain, and kidney of zebrafish after oral administration of Bacillus coagulans WH20 and infection with SVCV in Example 3 of the present invention.

[0019] Biological Deposits The strain provided by the present invention is deposited in China Center for Type Culture Collection (CCTCC), deposit address: Wuhan University, Wuhan, China, deposit number: CCTCC NO: M 20251025, deposit date: May 12, 2025, classification name: Bacillus coagulans ( Bacillus coagulans )WH20. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] Experimental procedures in the examples, where specific conditions are not specified, were generally performed in accordance with conventional methods in molecular biology, including but not limited to those described in M.R. Green's Molecular Cloning: A Laboratory Manual and Robert F. Weaver's Molecular Biology, or according to the recommendations of kit and instrument manufacturers. Unless otherwise specified, reagents and biological materials used in the examples were commercially available.

[0022] Currently, the existing technology lacks Bacillus coagulans that can significantly improve the hypoxia resistance and anti-viral infection resistance of aquatic animals.

[0023] In order to solve the problem in the prior art of lacking a Bacillus coagulans strain that can significantly improve the hypoxia resistance and anti-viral infection resistance of aquatic animals, the present invention provides a Bacillus coagulans strain and its application.

[0024] In a first aspect, the present invention provides a strain of Bacillus coagulans ( Bacillus coagulans )WH20, Bacillus coagulans ( Bacillus coagulans ) The accession number of WH20 is CCTCC NO:M 20251025.

[0025] The strain WH20 was isolated from the intestines of crucian carp from Wuhan, Hubei Province. 16S rDNA sequencing of the strain WH20 was performed, and its 16S rDNA sequence was subjected to BLAST multiple sequence alignment at NCBI (https: / / www.ncbi.nlm.nih.gov / ), and a phylogenetic tree was constructed. The results showed that the strain WH20 had a high degree of homology with Bacillus coagulans and was in the same branch as Bacillus coagulans strain MTCC5260. Based on the above identification results, the strain WH20 was named Bacillus coagulans ( Bacillus coagulans )WH20.

[0026] The present invention provides Bacillus coagulans ( Bacillus coagulans ) WH20 can effectively alleviate the inflammatory response of aquatic animals after hypoxia and / or SVCV infection, and significantly improve the survival rate of aquatic animals after hypoxia and / or SVCV infection. Therefore, it has good application prospects in aquaculture.

[0027] In a second aspect, the present invention provides a biological bacterial agent, comprising the above-mentioned Bacillus coagulans ( Bacillus coagulans )WH20.

[0028] In some embodiments, the biological inoculant is a liquid inoculant.

[0029] In some embodiments, the liquid inoculum contains Bacillus coagulans ( Bacillus coagulans )WH20 content ≥1×10 8 cfu / mL.

[0030] It is understandable that the biological agent can be selected from conventional dosage forms in the prior art according to actual use needs, for example, it can also be a solid agent, and the solid agent can be prepared using conventional methods in the art.

[0031] In a third aspect, the present invention provides a method for preparing the above-mentioned biological agent, comprising the following steps: Bacillus coagulans ) WH20 is inoculated into a liquid culture medium for cultivation, and the resulting culture is separated and resuspended in a solvent to obtain a biological agent.

[0032] The preparation method of the biological microbial agent provided by the present invention is simple, environmentally friendly, and has good biosafety.

[0033] It is understood that the liquid culture medium can be a common culture medium in the art, as long as it can meet the requirements of the Bacillus coagulans ( Bacillus coagulans ) Normal growth of WH20 is sufficient. Conventional culture conditions can be selected. In the present invention, the liquid culture medium is preferably LB medium.

[0034] In some embodiments, the separation comprises centrifugation at 5000-7000 rpm for 3-10 min.

[0035] In some embodiments, the solvent comprises at least one of PBS buffer and sterile water.

[0036] In a fourth aspect, the present invention provides the Bacillus coagulans ( Bacillus coagulans ) Use of WH20, any of the above-mentioned biological agents, or the biological agents obtained by the above-mentioned preparation methods in at least one of the following: A1) preparing drugs and / or feed additives for improving the hypoxia tolerance of aquatic animals; A2) preparing drugs and / or feed additives for improving the resistance of aquatic animals to aquatic viral infections.

[0037] In some embodiments, in A1), improving the hypoxia tolerance of aquatic animals includes at least one of inhibiting the inflammatory response caused by hypoxia in aquatic animals, improving the survival rate of aquatic animals after hypoxia, and reducing organ damage caused by hypoxia in aquatic animals.

[0038] In some embodiments, in A2), improving the ability of aquatic animals to resist aquatic virus infection includes at least one of inhibiting the inflammatory response caused by aquatic animals infected with aquatic viruses, improving the survival rate of aquatic animals infected with aquatic viruses, and reducing organ damage caused by aquatic animals infected with aquatic viruses.

[0039] In some embodiments, the aquatic virus comprises a carp spring viremia virus.

[0040] It is understandable that the aquatic virus can be a conventional aquatic virus in the prior art. In the present invention, the aquatic virus preferably includes carp spring viremia virus.

[0041] In some embodiments, the organ includes at least one of the brain and the intestine.

[0042] It is understood that the types of organs may include conventional organs in the prior art. In the present invention, the organs preferably include at least one of the brain and the intestine.

[0043] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0044] Example 1 Screening and identification of strain WH20 Crucian carp from Wuhan, Hubei Province were selected, and their intestines were removed and ground into a homogenate with 200 μL of sterile saline. 50 μL (10 -3 , 10 -4 and 10 -5) were inoculated onto LB solid medium and incubated at 28°C for 48 hours in an aerobic or anaerobic environment. Individual colonies on the LB solid medium were selected and named WH5, WH15, and WH20. These strains were inoculated into LB liquid medium and incubated at 28°C and 180 rpm for 48 hours. The incubated bacterial suspension was centrifuged at 6000 rpm for 5 minutes and resuspended in PBS buffer to obtain WH5, WH15, and WH20 bacterial cultures, respectively (the content of WH5, WH15, and WH20 strains was 1×10 8 cfu / mL).

[0045] Bighead carp were purchased from a fishery and acclimatized in a 28°C breeding environment for two weeks. Commercial feed was fed every morning and evening at a rate of 3% of the bighead carp's body weight. After the adaptation period, healthy and disease-free bighead carp with similar individual size and specifications were selected. The dissolved oxygen content of the breeding water was controlled at 6-14 mg / L by an air pump, and the pH value of the water was controlled at 6.8-7.8. The bighead carp were divided into a control group, a WH5 bacterial agent oral injection group, a WH15 bacterial agent oral injection group, and a WH20 bacterial agent oral injection group, with an injection volume of 100 μL. The control group was orally injected with the same volume of PBS as a control. After 7 days of continuous oral injection, the bighead carp in different treatment groups were subjected to hypoxia stress under 5% O2, and the survival status within 240 minutes was observed and recorded. The results are as follows Figure 1 shown.

[0046] from Figure 1 It can be seen that WH5, WH15 and WH20 strains can all improve the hypoxia tolerance of bighead carp, and the WH20 strain has the strongest effect on improving the hypoxia tolerance of bighead carp.

[0047] Next, single colonies of the WH20 strain were selected and re-incubated in 1 mL of LB medium in an aerobic or anaerobic flask. PCR amplification was performed using universal primers (27F and 1492R) and the extracted genomic DNA from the bacterial suspension as a template. The PCR amplification products were then sequenced.

[0048] The sequence (SEQ ID NO: 1) was aligned by BLAST in NCBI (https: / / www.ncbi.nlm.nih.gov / ) and a phylogenetic tree was constructed. The results are shown in Figure 2 shown.

[0049] from Figure 2 It can be seen from the results that the strain WH20 has a high homology with Bacillus coagulans and is in the same branch as the Heyndrickxiacoagulans DSM 1 strain. Based on the above identification results, the strain WH20 was named Bacillus coagulans ( Bacillus coagulans )WH20.

[0050] Example 2 Bacillus coagulans WH20 improves zebrafish's tolerance to hypoxia This example takes zebrafish as an example and detects the effect of feeding zebrafish with Bacillus coagulans ( Bacillus coagulans ) Survival rate under hypoxia stress after WH20.

[0051] The preparation of the Bacillus coagulans inoculum was as follows: a single colony of Bacillus coagulans WH20 was inoculated into LB liquid medium and incubated at 28°C and 180 rpm for 48 h; the incubated bacterial liquid was centrifuged at 6000 rpm for 5 min, and the bacteria were resuspended in PBS buffer to obtain the Bacillus coagulans inoculum (the content of Bacillus coagulans WH20 was 1×10 8 cfu / mL).

[0052] The method is as follows: Adult three-month-old zebrafish were purchased from the National Zebrafish Resource Center and acclimated for two weeks at 28°C, fed Artemia spp. daily in the morning and evening. After the acclimation period, healthy, disease-free zebrafish of similar size and size were selected. Dissolved oxygen in the culture water was controlled at 6-14 mg / L using an air pump, and the pH was maintained at 6.8-7.8. The zebrafish were divided into a control group and a group receiving oral administration of Bacillus coagulans. The control group received 100 μL of the Bacillus coagulans inoculum, while the control group received the same volume of PBS as a control. After seven days of oral administration, the zebrafish were subjected to hypoxia using a Ruskinn Invivo2 300 workstation. Six hours before the experiment, the culture water was placed in a chamber to induce hypoxia. Ten adult zebrafish (0.35 ± 0.03 g) were placed in a 1-L beaker in each group, and 400 mL of the treated culture water was added. The zebrafish were treated in a room with an oxygen concentration of 6% and a water temperature of 28°C. The dead fish that lost their balance were counted every hour, and the survival of the zebrafish was observed and recorded. Figure 3 shown.

[0053] from Figure 3 It can be seen that compared with the control group, the mortality rate of the Bacillus coagulans oral irrigation group was significantly reduced, down 43.33% compared with the control group. The results showed that Bacillus coagulans WH20 can significantly improve the zebrafish's tolerance to hypoxia.

[0054] Furthermore, after 4 hours of hypoxia, the intestines and brains of zebrafish in each group were fixed with 4% paraformaldehyde, dehydrated, transparent, wax-impregnated, embedded and sectioned, and H&E staining was used to observe the changes in the tissue structure of the organs. Figure 4 shown.

[0055] from Figure 4It can be seen that compared with the control group, the pathological damage caused by hypoxia in various organs of zebrafish treated with oral gavage of Bacillus coagulans was significantly alleviated. The results showed that Bacillus coagulans WH20 significantly reduced the intestinal and brain damage caused by hypoxia.

[0056] Furthermore, after 4 hours of hypoxia, the intestine (Intestine) and brain (Brain) of the zebrafish in the above-mentioned treatment groups were taken, and total RNA was extracted. After reverse transcription, fluorescence quantification was performed for relative quantitative detection of inflammatory factors IL-1β, IL-8, TNF-α and TLR-4.

[0057] Among them, the quantitative detection gene primer sequences are as follows: il-1β-F: 5'-GTCATCATCGCCCTGAACAGA-3' (SEQ ID NO: 2); il-1β-R: 5'-GTAAGACGGCACTGAATCCAC-3' (SEQ ID NO: 3); il-8-F: 5'-TTAAACAGAAAGCCGACGC-3' (SEQ ID NO: 4); il-8-R: 5'-TTGTCATCAAGGTGGCAATGA-3' (SEQ ID NO: 5); tnf-α-F: 5'-GCTGGATCTTCAAAGTCGGGTGTA-3' (SEQ ID NO: 6); tnf-α-R: 5'-TGTGAGTCTCAGCACACTTCCATC-3' (SEQ ID NO: 7); tlr4-F: 5'-ACAGATCACCTGGACAGCAAG-3' (SEQ ID NO: 8); tlr4-R: 5'-TGCTTGAAAGTCCCGCATGT-3' (SEQ ID NO: 9).

[0058] Test results such as Figure 5 shown.

[0059] from Figure 5 It can be seen that compared with the control group, the expression levels of inflammatory factors IL-1β, IL-8, TNF-α and TLR4 in the intestine and brain of zebrafish treated with oral gavage of Bacillus coagulans after hypoxia were significantly reduced. The results showed that Bacillus coagulans can significantly reduce the levels of inflammatory factors in the brain (Brain) and intestine (Intestine) of zebrafish after hypoxia.

[0060] Example 3 Bacillus coagulans WH20 inhibits SVCV infection in zebrafish In this example, zebrafish was used as an example to detect the oral administration of Bacillus coagulans ( Bacillus coagulans ) Effects of WH20 on SVCV infection in fish.

[0061] The preparation of the Bacillus coagulans inoculum was as follows: a single colony of Bacillus coagulans WH20 was inoculated into LB liquid medium and incubated at 28°C and 180 rpm for 48 h; the incubated bacterial liquid was centrifuged at 6000 rpm for 5 min, and the bacteria were resuspended in PBS buffer to obtain the Bacillus coagulans inoculum (the content of Bacillus coagulans WH20 was 1×10 8 cfu / mL).

[0062] Specifically, the method is as follows: Adult three-month-old zebrafish were purchased from the National Zebrafish Resource Center and adapted to be raised in a 28°C breeding environment for two weeks, and were fed with Artemia worms every morning and evening. After the adaptation period, healthy and disease-free zebrafish with similar individual size and specifications were selected. The selected zebrafish were cooled by 1°C every day, and the water temperature was uniformly reduced from 28°C to 16°C, and maintained at 16°C for subsequent experiments. The dissolved oxygen content of the breeding water was controlled at 6-14 mg / L by an air pump, and the pH value of the water was controlled at 6.8-7.8. The zebrafish were divided into a control group and an oral infusion of Bacillus coagulans group. The infusion volume of Bacillus coagulans was 100μL, and the control group was orally infused with the same volume of PBS as a control. 10μL SVCV virus suspension (content of 10 4 PFU) were injected into zebrafish along the base of the pelvic fin and the survival rate within 14 days was observed and recorded. Figure 6 shown.

[0063] from Figure 6 It can be seen that the survival rate of zebrafish infected with SVCV in the control group was 3.85%, while oral administration of Bacillus coagulans significantly increased the survival rate of zebrafish infected with SVCV to 26.92%. The results show that Bacillus coagulans WH20 can significantly improve the survival rate of zebrafish infected with SVCV.

[0064] Furthermore, on the 7th day after infection, the heart, spleen, liver, intestine, kidney and brain of the zebrafish in the above-mentioned treatment group were collected to extract total RNA, and the relative quantitative detection of IL-1β was performed by fluorescence quantification after reverse transcription (the quantitative detection primers were the same as those in Example 2). The results are shown in FIG. Figure 7 shown.

[0065] from Figure 7It can be seen that Bacillus coagulans WH20 can significantly reduce the expression level of il-1β in the heart, spleen, liver, intestine, kidney and brain of zebrafish after infection with SVCV.

[0066] Furthermore, on the 5th day after infection, the liver, brain, and kidney of zebrafish uninfected with SVCV, orally injected with Bacillus coagulans WH20, infected with SVCV, or orally injected with Bacillus coagulans and SVCV were fixed in 4% paraformaldehyde, dehydrated, transparent, wax-impregnated, embedded, and sectioned. The changes in the tissue structure of the organs were observed after H&E staining. The results are as follows: Figure 8 shown.

[0067] from Figure 8 It can be seen that compared with the control group, the pathological damage caused by viral infection in various organs of zebrafish treated with Bacillus coagulans WH20 was significantly alleviated after SVCV infection. The results showed that Bacillus coagulans WH20 significantly reduced the pathogenicity of SVCV infection in zebrafish.

[0068] In summary, Bacillus coagulans WH20 can effectively inhibit the inflammatory response caused by carp spring viremia virus or hypoxia, and oral administration of Bacillus coagulans WH20 can effectively improve the survival rate of fish infected with SVCV or hypoxia. Therefore, Bacillus coagulans WH20 can be developed as a probiotic for the prevention and control of viruses or hypoxia in the aquatic industry, which is of great significance for the prevention and control of aquatic viruses and hypoxia.

[0069] 16S rDNA sequence of strain WH20 (SEQ ID NO: 1)

Claims

1. A strain of Bacillus coagulans WH20, characterized in that: The deposit number of the Bacillus coagulans WH20 is CCTCCNO: M 20251025.

2. A biological agent, characterized in that: The invention comprises the Bacillus coagulans WH20 according to claim 1.

3. The biological agent according to claim 2, characterized in that The biological bacterial agent is a liquid bacterial agent.

4. The biological agent according to claim 3, characterized in that The content of Bacillus coagulans WH20 in the liquid bacterial agent is ≥1×10 8 cfu / mL.

5. A method for preparing a biological agent according to any one of claims 2 to 4, characterized in that: The method comprises the following steps: inoculating the Bacillus coagulans WH20 according to claim 1 into a liquid culture medium for cultivation, separating the obtained culture and then resuspending it with a solvent to obtain a biological bacterial agent.

6. Use of the Bacillus coagulans WH20 according to claim 1, the biological agent according to any one of claims 2 to 4, or the biological agent prepared according to claim 5 in at least one of the following: A1) Preparation of drugs and / or feed additives for improving the hypoxia tolerance of aquatic animals; A2) Preparation of drugs and / or feed additives for improving the resistance of aquatic animals to aquatic viral infections.

7. The use according to claim 6, characterized in that In A1), the improving the hypoxia tolerance of aquatic animals includes at least one of inhibiting the inflammatory response caused by hypoxia in the aquatic animals, improving the survival rate of the aquatic animals after hypoxia, and reducing organ damage caused by hypoxia in the aquatic animals.

8. The use according to claim 6, characterized in that In A2), the improvement of the ability of aquatic animals to resist aquatic virus infection includes at least one of inhibiting the inflammatory response caused by the infection of the aquatic animals with aquatic viruses, improving the survival rate of the aquatic animals infected with aquatic viruses, and reducing the organ damage caused by the infection of the aquatic animals with aquatic viruses.

9. The use according to claim 8, characterized in that The aquatic viruses include carp spring viremia virus.

10. The use according to claim 7 or 8, characterized in that The organ includes at least one of a brain and an intestine.

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