Rat tail fungus and its use

Abstract

The present application provides a mouse tail bacteria and application thereof, and belongs to the technical field of biotechnology. Muricauda beolgyonensis SY152020042, the preservation number is CCTCC NO:M 20251495, and the nucleotide sequence is shown as SEQ ID NO:1. The anti-vibrio preparation prepared based on the mouse tail bacteria can achieve broad-spectrum, instant and low-cost vibrio prevention and treatment, and effectively curb the spread of drug resistance and environmental pollution.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of biotechnology, in particular, to a murine caecum bacteria and its application. BACKGROUND

[0002] Vibrio disease is a systemic infectious disease of aquatic animals caused by bacteria in the family Vibrio, which can cause septicemia, gastroenteritis and skin ulceration, and has become one of the most destructive bacterial diseases in global aquaculture. The family Vibrio contains 6 genera and 143 species, among which the most pathogenic and common are Vibrio parahaemolyticus (Vp), Vibrio harveyi (Vh), Vibrio alginolyticus (Va) and Vibrio anguillarum (Va). Vibrio parahaemolyticus Vibrio harveyi Vibrio alginolyticus Vibrio anguillarum These pathogens multiply rapidly in warm waters (15-30℃) and low-salinity environments, and are prone to outbreaks in summer, posing a serious threat to aquaculture in tropical and subtropical regions.

[0003] At present, antibiotics are still the main means to prevent and treat vibrio disease, such as chloramphenicol, gentamicin, norfloxacin, etc., which have a certain inhibitory effect on Vibrio. However, the extensive use and abuse of antibiotics have led to the rapid spread of drug-resistant strains, the enhancement of multiple drug resistance mechanisms, and the accumulation of drug resistance genes in aquatic environments, which not only reduces the treatment effect, but also poses a potential threat to the ecosystem and public health. In particular, Vibrio parahaemolyticus, Vibrio alginolyticus and other bacteria isolated from aquatic farming systems in many countries and regions in Asia have widely carried β-lactamase genes, efflux pump systems and biofilm-related factors, showing high resistance to a variety of commonly used antibiotics.

[0004] As an alternative, vaccination has become an important development direction for the prevention and control of vibrio disease. Existing aquatic vibrio vaccines mainly include inactivated vaccines, attenuated live vaccines and subunit vaccines. Although some vaccines have shown good protection effect in specific species, they still face many limitations, such as poor regional adaptability, limited immune effect due to the defects of the immune system of crustaceans, high cost of vaccines and safety risks of attenuated vaccines, etc. SUMMARY

[0005] The embodiments of the present application aim to at least solve one of the technical problems in the related art. To this end, the embodiments of the present application provide a murine caecum bacteria and its application in preparing an anti-vibrio preparation, which can achieve broad-spectrum, instant and low-cost prevention and treatment of Vibrio, effectively curb the spread of drug resistance and environmental pollution.

[0006] In a first aspect, the embodiments of the present application provide a murine caecum bacteria Muricauda beolgyonensis SY152020042. According to the embodiments of the present application, the murine caecum bacteria Muricauda beolgyonensis ​​​The accession number of SY152020042 is CCTCC NO: M 20251495.

[0007] The *Ratella* species provided in this application embodiment were isolated from sediment samples collected from the Madeke Trench using a gradient dilution coating method. The aforementioned *Ratella* species, its fermentation broth, its metabolites, or its bacterial suspension are effective against *Vibrio anguillarum* (…). Vibrio anguillarum ATCC 43307), Vibrio parahaemolyticus ( Vibrio parahaemolyticus ATCC 17802) exhibits significant inhibitory activity. It is named... Muricauda beolgyonensis SY152020042, deposited on July 1, 2025 at the China Center for Type Culture Collection (CCTCC), Wuhan, Hubei Province, China, with accession number CCTCC NO: M20251495. In an exemplary embodiment, the *Symplocos rubrum*... Muricauda beolgyonensis The 16S rDNA sequence of SY152020042 is shown in SEQ ID NO: 1.

[0008]

[0009] Secondly, this application provides a culture selected from *Symplocos rubrum*. Muricauda beolgyonensis SY152020042 includes live cells, inactivated cells, metabolites, fermentation broth, or bacterial suspension.

[0010] Thirdly, embodiments of this application provide a microbial agent or preparation containing *Ravenous Salmonella* or its fermentation broth or its metabolites or its suspension as described in the first aspect.

[0011] In an exemplary embodiment, the microbial agent or preparation includes: aquatic feed additives, cleaning agents, or disinfectants.

[0012] Fourthly, embodiments of this application provide a composition comprising the first aspect of *Ravenous Salmonella* or its fermentation broth or its metabolites or its suspension.

[0013] In exemplary embodiments, the aforementioned composition further includes at least one of an antibiotic for anti-Vibrio, a probiotic, and a traditional Chinese medicine.

[0014] Fifthly, embodiments of this application provide a method for improving the survival rate of aquatic products, the method comprising: adding *Rhizopus* or its fermentation broth or its metabolites or its suspension from the first aspect to water.

[0015] In a sixth aspect, embodiments of this application provide a method for preparing a bactericidal compound, the method comprising: fermenting and culturing *Raphinatus* from the first aspect to obtain the bactericidal compound.

[0016] In an exemplary embodiment, the aforementioned bactericidal compound includes: fermentation broth, and a metabolite extract obtained based on the fermentation broth.

[0017] Seventhly, embodiments of this application provide the application of the aforementioned *Salvia miltiorrhiza* in the preparation of anti-Vibrio products.

[0018] In an exemplary embodiment, the product includes at least one of a food preservative, a disinfectant, and a feed additive.

[0019] In an exemplary embodiment, the Vibrio includes at least one of Vibrio parahaemolyticus, Vibrio harveyi, Vibrio alginolyticus, and Vibrio anguillarum.

[0020] The *Rat's Tail* fungus of the present application has the following beneficial effects:

[0021] This application embodiment obtains *Raphaelum sarmentosum* strains with significant antagonistic ability against Vibrio through isolation and screening. It achieves growth inhibition of common aquatic pathogens such as *Vibrio parahaemolyticus* using a non-antibiotic approach, effectively replacing the use of traditional chemical drugs. This significantly reduces the dependence of pathogens on antibiotics and the evolutionary trend of drug resistance, reduces the risk of the spread of drug-resistant genes in the aquatic environment, and controls public health threats from the source.

[0022] The *Ravenous Sarcoptes* strain and its metabolites provided in this application exert a broad-spectrum inhibitory effect on *Vibrio* through mechanisms such as nutrient competition. This has the advantage of not requiring antigen-specific recognition, overcoming the limitations of existing vaccines that require design targeting specific strains and have limited protection. Furthermore, the formulation can be directly applied through feed additives or water spraying, eliminating the need for complex steps such as vaccine inactivation, adjuvant addition, and cold chain storage and transportation. This simplifies the application process, reduces prevention and control costs, and has significant potential for widespread application.

[0023] The *Ravenous Spore* strain of this application originates from the marine environment, possesses excellent salt tolerance and environmental adaptability, can stably colonize in aquaculture systems, is not easily rejected by native microorganisms, and effectively inhibits the proliferation of Vibrio through niche competition. This overcomes the shortcomings of terrestrial probiotics in water bodies, such as short-lasting effects and easy concentration degradation, and provides a new strategy for the regulation of aquatic ecological microecology.

[0024] This application embodiment, through systematic isolation and culture, molecular identification and functional experiments, clarifies that the *Ravenous Spore* strain and its fermentation broth or metabolites have good Vibrio inhibitory activity in vitro, providing a scientific basis for the development of microecological preparations or environmental antibacterial products, and expanding the application space of marine microbial resources in the field of healthy aquaculture.

[0025] In addition, the embodiments of this application also conducted antibiotic susceptibility testing on the strain of *Ratheus cuspidatum* to assess its own drug resistance level, confirming that the strain is a natural non-pathogenic bacterium, with no risk of virulence reversion as in attenuated vaccine preparations, and its metabolites can be naturally degraded, without causing drug residue pollution in water bodies, and has good safety, making it suitable for large-scale promotion and application.

[0026] Additional aspects and advantages of embodiments of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of embodiments of this application. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is provided in one embodiment of the present application. Muricauda beolgyonensis A schematic diagram showing the test results of the antibacterial ability against Vibrio anguillarum;

[0029] Figure 2 This is provided in one embodiment of the present application. Muricauda beolgyonensis A schematic diagram of the results of the antibacterial activity test against Vibrio parahaemolyticus; where AMP (ampicillin): positive control; methanol: negative control; and Sarcoptes aureus: sample group. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0031] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or server that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0032] It is understood that, based on the embodiments of this application, further implementation optimizations and application expansions can be carried out as follows:

[0033] 1. Fermentation process optimization and formulation development

[0034] To improve Muricauda beolgyonensis The biomass and antagonistic metabolite production of SY152020042 allow for systematic optimization of its fermentation process. For example, based on the strain's physiological characteristics, the composition and ratio of carbon sources, nitrogen sources, and trace elements in the culture medium can be screened and optimized. Key parameters during fermentation, such as fermentation temperature, initial pH, aeration rate, and stirring rate, can be controlled to improve cell growth rate and metabolite yield.

[0035] In terms of formulation development, various forms of formulations can be developed for different application scenarios (such as feed additives, water spraying, and facility surface disinfection), including freeze-dried powder formulations, microencapsulated formulations, and fermentation broth products. By optimizing carrier materials and encapsulation technology, the stability and preservation of strains or metabolites during storage and transportation can be improved, as well as their release effect and adaptability during use, thereby expanding their practical application in aquaculture systems.

[0036] 2. Combined application and integrated prevention and control strategies

[0037] In actual aquaculture disease control, the *Salvia miltiorrhiza* preparation of this application embodiment can also be used in combination with other aquatic disease control methods to form a diversified comprehensive prevention and control strategy. For example, the antagonistic bacteria can be used in conjunction with existing vaccination programs to leverage its immediate antagonistic advantage in the early stages of aquaculture or under stress, while simultaneously establishing a long-lasting specific immune barrier; it can also be fed in combination with functional probiotics, traditional Chinese medicine extracts, etc., to synergistically regulate the intestinal microecology and enhance the body's immunity through multiple pathways, thereby strengthening the overall defense against pathogens such as Vibrio.

[0038] This joint prevention and control approach not only helps improve the breadth and efficiency of disease control, but also reduces dependence on single drugs or methods, delays the emergence of drug-resistant strains, and enhances the ecological stability and sustainability of aquaculture systems.

[0039] It is understood that the *Ravenous Salmonella* strains, their metabolites, or their suspensions provided in this application, in addition to their potential use in controlling Vibrio infections in aquaculture systems, have broad application potential, including but not limited to the following technical fields:

[0040] 1. Water quality maintenance in aquariums and oceanariums

[0041] The strains provided in this application can be applied to enclosed or semi-enclosed ornamental aquatic environments, such as aquariums and oceanariums. Through their antagonistic effect on pathogenic microorganisms such as Vibrio, they can effectively control the structure of the aquatic microbial community, reduce the load of harmful bacteria, and reduce the risk of infection for aquatic animals, thereby maintaining clean water quality and a stable ecological balance. This helps improve the health and survival rate of ornamental fish, crustaceans, and shellfish, while also reducing the frequency of water maintenance and water changes, thus saving operating costs.

[0042] 2. Marine ranching and aquaculture systems

[0043] In open or semi-open marine ranches and aquaculture areas, the strains described in this application can serve as ecotype regulators to improve the microecological environment of aquaculture waters, inhibit the spread and colonization of pathogenic Vibrio, thereby reducing the risk of disease outbreaks. Long-term application helps maintain the health of aquaculture organisms, promotes their growth and development, increases unit output efficiency, and supports the sustainable development and utilization of marine fishery resources.

[0044] 3. Food preservation and processing

[0045] The *Ravenous Sinapis albopictus* strain of this application exhibits natural inhibitory effects against foodborne pathogens such as *Vibrio parahaemolyticus*, demonstrating its potential application in the field of food preservation. The metabolites or extracts of this strain can be used in the processing of aquatic products, such as for surface spraying, soaking, or wrapping of seafood, to delay spoilage, inhibit the growth of pathogens, extend shelf life, and improve food safety and commercial value.

[0046] 4. Marine environmental governance

[0047] The strains described in this application originate from marine ecosystems, exhibiting strong adaptability and stable ecological niches, demonstrating excellent survival and colonization capabilities in seawater environments. Their metabolic activity can be used for the regulation and purification of microbial communities in polluted sea areas. Especially in the context of high Vibrio abundance pollution, they can reduce pathogen concentrations and improve water quality through inter-bacterial competitive inhibition mechanisms, potentially contributing to the restoration and balance of regional ecosystems in marine ecological restoration projects.

[0048] 5. Biopharmaceuticals and Development of Novel Antimicrobial Resources

[0049] The strains described in this application exhibit stable anti-Vibrio activity in vitro and have the potential to become novel antimicrobial agents. Further extraction of metabolites and purification of active components, along with structural analysis and functional evaluation, can be used to develop naturally derived antimicrobial drugs, biopesticides, or functional formulations. This will provide new sources of microbial active substances for human medicine, animal health, and agricultural disease control, promoting the development of biomedicine and green agriculture.

[0050] Unless otherwise specified, the techniques or conditions described in the following examples were performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0051] Example 1: Isolation and Identification of *Ratheus chinensis* Strains

[0052] To obtain a marine-derived strain with anti-Vibrio activity, this embodiment isolated and screened a strain of *Salvia miltiorrhiza* with significant antagonistic activity from deep-sea sediment samples. Muricauda beolgyonensisThe organism was systematically identified through morphological observation, 16S rRNA sequencing, and whole-genome analysis. The specific steps are as follows:

[0053] 1. Strain Isolation

[0054] Approximately 2 g of sediment samples were collected from the Madeke Trench area and aseptically diluted 10-fold in sterile physiological saline. A suitable amount of each dilution was plated onto 2216E marine bacteria-specific agar plates and incubated at 28°C for 48 hours. After significant colony growth, single colonies with different morphological characteristics were selected for purification and amplification. Through continuous transfer and plating, a morphologically stable pure culture strain was obtained, designated SY152020042.

[0055] 2. Molecular identification of bacterial strains

[0056] To clarify the taxonomic position of this strain, molecular identification was performed using 16S rRNA gene sequencing. Genomic DNA was extracted from the strain and amplified by PCR using universal 16S primers to obtain the full-length gene sequence (SEQ ID NO: 1). Alignment analysis of this sequence using the EzBioCloud database showed that the 16S rRNA gene similarity between this strain and *Flagellimonas beolgyonensis* (Accession: KCTC 23501) was 99.85%. Based on its gene sequence characteristics, colony morphology, and ecological origin, it was preliminarily classified as a candidate strain of the *Muricauda* genus.

[0057] 3. Whole-genome sequencing and phylogenetic annotation

[0058] The strain was further sequenced using DNBSEQ™ sequencing technology to obtain a complete, high-quality genome sequence. Assembly results showed that the full-length genome was 4,384,941 bp, consisting of a closed circular chromosome; the N50 was 233,907 bp; the genome completeness was 99.67%, and the contamination level was 1.740%. According to the MIMAG standard for microbial genomes, this is classified as a "high-quality" genome.

[0059] The taxonomic position of this strain is clearly defined by annotation in the GTDB database (Release R207):

[0060] Kingdom: Bacteria; Phylum: Bacteroidota; Class: Bacteroidia; Order: Flavobacteriales; Family: Flavobacteriaceae; Genus: Muricauda; Species: Muricauda beolgyonensis, consistent with the 16S identification results.

[0061] 4. Annotation of secondary metabolite gene clusters

[0062] The entire genome of this strain was analyzed using the antiSMASH v7.0 platform to identify biosynthetic gene clusters (BGCs). The results showed that the strain's genome contains two complete biosynthetic gene clusters. One of the BGCs is a potential novel gene cluster not annotated in databases, suggesting that this strain may possess unique and undiscovered metabolic capabilities, and has the potential to further develop novel antimicrobial active substances.

[0063] This embodiment successfully obtained a strain of *Rataria sagittatum* with complete genomic information derived from deep-sea sediments. Muricauda beolgyonensis SY152020042.

[0064] Example 2: Detection of antibacterial activity of *Salvia miltiorrhiza* strains

[0065] To evaluate the inhibitory effect of the *Rhizoctonia solani* strain obtained in Example 1 on *Vibrio*, its fermentation broth and crude extracts of metabolites were prepared, and their anti-Vibrio activity was detected using the Oxford cup diffusion method and the paper disc diffusion method, as detailed below:

[0066] 1. Preparation of fermentation broth and crude extracts of metabolites

[0067] 1.1 Preparation of fermentation broth

[0068] Will Muricauda beolgyonensis A single colony of strain SY152020042 was picked from a purified plate and inoculated into 2216E marine medium. The culture was then incubated at 28°C and 200 rpm for 2 days with shaking to obtain the seed culture. Subsequently, 1 mL of the seed culture was inoculated into 10 mL of 2216E medium and incubated at 28°C with shaking (230 rpm) for 3 days. The resulting liquid was the fermentation broth of this strain.

[0069] 1.2 Preparation of crude extracts of metabolites

[0070] The resulting fermentation broth (total volume 40 mL) was centrifuged to remove bacterial cells, and the supernatant was collected. Metabolites were enriched using an HLB solid-phase extraction column (SPE) with a single loading capacity of 10 mL. The procedure is as follows:

[0071] The SPE column was activated sequentially with 10 mL of methanol and 10 mL of pure water.

[0072] The pretreated supernatant was loaded into the SPE column in batches until all 40 mL was loaded.

[0073] After each sample loading, apply negative pressure to dry the sample.

[0074] Rinse twice with 10 mL of pure water, and drain the residual liquid from the column each time.

[0075] Add 5 mL of methanol (eluent) and soak for 10 minutes, then collect the eluent.

[0076] Add 5 mL of methanol again to elute and collect;

[0077] The two eluents were combined and concentrated under reduced pressure to obtain a crude extract of metabolites, which was then stored in methanol for later use.

[0078] 2. Antibacterial activity test

[0079] 2.1 Evaluation of the antibacterial activity of the fermentation broth against Vibrio anguillarum

[0080] The Oxford cup diffusion method was used to detect the activity of Vibrio anguillarum in the fermentation broth. Vibrio anguillarum The antibacterial activity of *Vibrio anguillarum* (ATCC 43307) was investigated. An appropriate amount of *Vibrio anguillarum* indicator bacteria was added to a 2216E agar plate and mixed thoroughly. Four Oxford cups were placed on the agar surface, and 100 μL of fermentation broth was added to each cup. The plates were incubated at 28°C for 18 hours, and the diameter of the inhibition zone was observed and measured. The experimental results are as follows: Figure 1 As shown, Muricauda beolgyonensis The fermentation broth exhibits antibacterial activity against Vibrio anguillarum, forming an average inhibition zone diameter of 12.0 ± 0.2 mm with clear and distinct edges.

[0081] 2.2 Evaluation of the antibacterial activity of crude metabolites against Vibrio parahaemolyticus

[0082] The effects of crude metabolites on Vibrio parahaemolyticus (V. parahaemolyticus) were evaluated using the disk diffusion method. Vibrio parahaemolyticus The antibacterial effect of ATCC 17802 was assessed. The crude extract of the metabolites was dissolved in methanol to a concentration of 100 μg / paper disc, and then added dropwise onto sterile filter paper discs, which were then thoroughly dried to allow methanol to evaporate. The following groups were established:

[0083] Sample group: Crude extract of Muricauda beolgyonensis metabolites (100 μg);

[0084] Positive control group: ampicillin (10 μg);

[0085] Solvent control group: pure methanol.

[0086] Various paper discs were affixed to 2216E agar plates containing Vibrio parahaemolyticus. The plates were then inverted and incubated at 37°C for 16 hours. After incubation, the inhibition zones were observed and measured. Results are as follows: Figure 2 As shown, the diameter of the inhibition zone in the sample group was 15.0 ± 0.2 mm; the positive control group formed an obvious inhibition zone; no inhibition zone was observed in the solvent control group, indicating that methanol itself does not have antibacterial activity.

[0087] Example 3: Antibiotic susceptibility testing of *S. sarcodactylis* strains

[0088] To assess the susceptibility of the *Ravenous Strain* from Example 1 to commonly used antibiotics, the disk diffusion method was used to detect its antibiotic resistance. The specific method and results are as follows:

[0089] 1. Experimental Materials and Methods

[0090] Select Muricauda beolgyonensis Strain SY152020042 was cultured on 2216E marine bacteria medium. After bacterial activation, the culture was evenly spread onto the surface of agar plates. After the surface dried, standard antibiotic susceptibility test discs containing different antibiotics were attached to the plates. The antibiotics tested and their dosages were as follows: teicoplanin (30 μg / disc), vancomycin (30 μg / disc), chloramphenicol (30 μg / disc), tetracycline hydrochloride (30 μg / disc), erythromycin (15 μg / disc), gentamicin (10 μg / disc), and kanamycin (30 μg / disc). After mounting, the culture dishes were sealed with sealing film and incubated upside down in a 28°C thermostatic incubator for 24 hours.

[0091] 2. Result Judgment Criteria

[0092] After incubation, observe and accurately measure the diameter of the inhibition zone around each antibiotic disc. Sensitivity grading is determined according to the following criteria:

[0093] Inhibition zone diameter ≥ 20 mm: Extremely sensitive (E)

[0094] Inhibition zone diameter 15–20 mm: Highly sensitive (S)

[0095] Inhibition zone diameter 10–15 mm: Moderately sensitive (I, Intermediate)

[0096] Inhibition zone diameter <10 mm: Resistant (R)

[0097] The results are shown in Table 1. Muricauda beolgyonensisThe strain is extremely sensitive to teicoplanin, vancomycin, chloramphenicol, tetracycline hydrochloride, erythromycin, gentamicin, and kanamycin.

[0098] Table 1 Muricauda beolgyonensis Antibiotic susceptibility test results of strains

[0099]

[0100] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0101] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application without departing from the principles and spirit of this application.

Claims

1. A strain of rat-tail fungus Muricauda beolgyonensis SY152020042, characterized in that, The accession number is CCTCC NO: M 20251495.

2. The *Symplocos rubrum* according to claim 1 Muricauda beolgyonensis SY152020042, characterized in that, Its 16S rDNA sequence is shown in SEQ ID NO:

1.

3. A culture, characterized in that, The culture includes *Rat's tail* as described in claim 1 or 2. Muricauda beolgyonensis Live bacteria of SY152020042.

4. A microbial inoculant or preparation, characterized in that, The microbial agent or preparation contains the *Raphaelum sarmentosum* as described in claim 1.

5. The microbial agent or preparation according to claim 4, characterized in that, The microbial agents or preparations include: aquatic feed additives, cleaning agents, or disinfectants.

6. A composition, characterized in that, Including the *Rattail* as described in claim 1.

7. The composition according to claim 6, characterized in that, The composition also includes at least one of antibiotics, probiotics, and traditional Chinese medicine.

8. A method for preparing a bactericidal compound, characterized in that, include: The *Ratella* strain of claim 1 is fermented to obtain the bactericidal compound.

9. The method according to claim 8, characterized in that, The bactericidal compound includes: fermentation broth, and extracts of metabolites obtained from the fermentation broth.

10. The use of the *Rhizoctonia solani* according to claim 1 or 2 in the preparation of anti-Vibrio products, wherein the *Vibrio* is at least one of *Vibrio parahaemolyticus* and *Vibrio anguillarum*.

11. The application according to claim 10, characterized in that, The product includes at least one of food preservatives, disinfectants, and feed additives.

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