Heat-resistant bacillus pumilus P2-7 and application thereof in disease prevention and control of prawn culture

Abstract

The invention provides heat-resistant bacillus pumilus P2-7 and application thereof in disease prevention and control of prawn culture, and belongs to the technical field of bioengineering. The heat-resistant bacillus pumilus P2-7 provided by the invention is preserved in Guangdong Microbial Culture Collection Center on November 4, 2024, and the preservation number of the heat-resistant bacillus pumilus P2-7 is GDMCC NO. 65408. The strain is different from the traditional antibacterial bacillus in antagonism mode, cannot secrete metabolites with antibacterial activity, plays a role in a phagocytosis mode, can remarkably remove / inhibit pathogenic bacteria in water, can effectively prevent and control shewanella disease of prawns, and has a good application prospect. The composition also has a good effect of simultaneously preventing septicemia, acute hepatopancreas necrosis, white spot syndrome and infectious subcutaneous and hematopoietic necrosis in prawn culture production.

Description

Technical Field

[0001] The invention belongs to the technical field of bioengineering, and in particular relates to a thermotolerant Bacillus pumilus P2-7 and an application thereof in the prevention and control of shrimp aquaculture diseases. Background Art

[0002] Pseudomonas aeruginosa and Shewanella algae in water

[0003] Shewanella algae, Plesiomonas shigelloides, Photobacterium damselae, Acinetobacter venetianus, Enterobacter cloacae, Stenotrophomonas maltophilia

[0004] The presence of potential pathogens such as Stenotrophomonas maltophilia and Providencia rettgeri has become an important factor threatening shrimp farming and even human health. For example, Acinetobacter venetianus can cause red leg disease in whiteleg shrimp Penaeus vannamei (Huang X, et al. Acinetobacter venetianus, a potential pathogen of red leg disease in freshwater-cultured whiteleg shrimp Penaeus vannamei [J]. Aquaculture Reports, 2020, 18: 100543.), and Providencia rettgeri can cause red leg disease in Japanese shrimp (Cao H, et al. Phenotypic and genomic characterization of pathogenic Providencia rettgeri from kuruma shrimp Marsupenaeus japonicus. Transboundary and Emerging Diseases, 2022, 1-11.). Therefore, the control of these pathogens in water is extremely important for shrimp farming.

[0005] Bacteriophagic probiotics are a type of microorganisms with bacteriophagic properties, and are known as natural biological control factors for pathogenic bacteria. For example, bacteriophagic probiotics such as Bdellovibrio and Vibrio phagoides have been proven to have shown good application effects in the prevention and control of shrimp aquaculture diseases (Zhang Luping, et al. Application of Bdellovibrio to Prevent Vibrio Infection in Shrimp [J]. Advances in Fisheries Science, 2009, 30(1): 26-33. Zhao Yan. Preparation of Vibrio halophilus BL9 agent and its application in antibiotic-free aquaculture of white shrimp [D]. Huaqiao University, 2021.). However, these bacteriophagic probiotics are all Gram-negative bacteria, and there are few reports on bacteriophagic probiotics as Gram-positive bacteria and their application in the prevention and control of shrimp aquaculture diseases. Summary of the invention

[0006] The invention provides a thermotolerant Bacillus pumilus P2-7 and application thereof in the prevention and control of shrimp aquaculture diseases. The strain exerts its efficacy through phagocytosis, can significantly remove / inhibit pathogenic bacteria in water, and can effectively prevent and control shrimp Shewanella disease, and also has a good effect on preventing sepsis, acute hepatopancreatic necrosis, white spot syndrome, infectious subcutaneous and hematopoietic tissue necrosis in shrimp aquaculture production.

[0007] In order to achieve the above-mentioned purpose, the present invention provides a thermotolerant Bacillus pumilus P2-7, which was deposited in Guangdong Provincial Microbiological Culture Collection Center, Guangdong, China on November 4, 2024, with the deposit number GDMCCNO.65408.

[0008] Preferably, the nucleotide sequence of the thermotolerant Bacillus pumilus P2-7 is as shown in SEQ ID NO:1.

[0009] The present invention also provides a use of the thermotolerant Bacillus pumilus P2-7 according to the above technical solution in removing / inhibiting pathogenic bacteria in aquaculture water.

[0010] Preferably, the thermotolerant Bacillus pumilus P2-7 inhibits bacteria in a phagocytic manner.

[0011] Preferably, the pathogenic bacteria is selected from at least one of Pseudomonas aeruginosa FJ1-2, Shewanella algae SFH3, Plesiomonas shigelloides BD1, Photobacterium damselae YJ-1, Acinetobacter venetianus SHF1, Enterobacter cloacae HT2, Stenotrophomonas maltophilia WY1, and Providencia rettgeri S6.

[0012] The present invention also provides a use of the thermotolerant Bacillus pumilus P2-7 according to the above technical solution in the prevention and control of Shewanella disease in shrimp.

[0013] Preferably, the concentration of Shewanella algae SFH3 is 5.0×10 6 CFU / ml, adding 0.8 mg / L of thermotolerant Bacillus brevis P2-7 powder can increase the protection rate of shrimp against Shewanella disease to more than 82%.

[0014] The present invention also provides an application of the thermotolerant Bacillus pumilus P2-7 according to the above technical solution in disease prevention and control in shrimp farming production.

[0015] Preferably, in shrimp farming, simultaneously spraying 0.4 mg / L of thermotolerant Bacillus pumilus P2-7 powder and feeding feed containing 20 g / kg of thermotolerant Bacillus pumilus P2-7 powder can prevent the occurrence of sepsis, acute hepatopancreatic necrosis, white spot syndrome, infectious subcutaneous and hematopoietic tissue necrosis.

[0016] The present invention also provides a breeding feed, characterized in that it contains the heat-resistant Bacillus pumilus P2-7 described in the above technical solution as a feed raw material.

[0017] Compared with the prior art, the advantages and positive effects of the present invention are:

[0018] 1. The present invention isolates and identifies a thermotolerant brevis Bacillus P2-7 with broad-spectrum phagocytic activity from shrimp aquaculture sediment, which has good phagocytic effects on pathogenic bacteria such as Pseudomonas aeruginosa FJ1-2, Shewanella salinarum SFH3, Shigella-like Pseudomonas BD1, Photobacterium mermanii YJ-1, Acinetobacter venezuelae SHF1, Enterobacter cloacae HT2, Stenotrophomonas maltophilia WY1, and Providencia rettgeri S6, and can significantly remove / inhibit the above-mentioned pathogens in water.

[0019] 2. The thermotolerant Bacillus pumilus P2-7 provided by the present invention has a different antagonistic mode from the traditional antibacterial Bacillus and cannot secrete metabolites with antibacterial activity, but exerts its efficacy through phagocytosis, which can effectively prevent and control Shewanella disease in shrimp, and at the same time prevent sepsis, acute hepatopancreatic necrosis, white spot syndrome, infectious subcutaneous and hematopoietic tissue necrosis in shrimp farming and production. It also has a good effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the colony morphology of the thermotolerant Bacillus pumilus P2-7 provided in an embodiment of the present invention;

[0021] Figure 2 A schematic diagram of the phagocytic activity of the thermotolerant Bacillus pumilus P2-7 against various pathogenic bacteria provided in an embodiment of the present invention;

[0022] Figure 3 A schematic diagram of the plaque morphology of the thermotolerant Bacillus pumilus P2-7 provided in an embodiment of the present invention;

[0023] Figure 4 A schematic diagram of the bacterial morphology of the thermotolerant Bacillus pumilus P2-7 provided in an embodiment of the present invention;

[0024] Figure 5 A phylogenetic tree constructed based on the 16S rRNA gene sequence of Thermotolerant Bacillus brevis P2-7 provided in an embodiment of the present invention;

[0025] Figure 6 The antibacterial rate of the thermotolerant Bacillus pumilus P2-7 provided in the embodiment of the present invention against pathogenic bacteria in artificial simulated aquaculture water;

[0026] Figure 7 The average mortality rate of the thermotolerant Bacillus brevis P2-7 provided in the embodiments of the present invention in the prevention and control of Shewanella disease in white shrimp. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1 Isolation and screening of thermotolerant Bacillus pumilus

[0029] Experimental Materials

[0030] Shrimp culture sediment was collected from a farm in Shandong; Pseudomonas aeruginosa FJ1-2, Shewanella algae SFH3, Shigella-like Pseudomonas BD1, Photobacterium mermanii YJ-1, Acinetobacter venezuelae SHF1, Enterobacter cloacae HT2, Stenotrophomonas maltophilia WY1, and Providencia rettgeri S6 were provided by the National Aquatic Animal Pathogen Bank of Shanghai Ocean University; Whiteleg shrimp, healthy and disease-free, with an average weight of 0.08 g, was temporarily cultured in the laboratory for 14 days and was provided by Changyi Haifeng Aquaculture Co., Ltd.

[0031] Preparation of pathogenic bacterial suspension

[0032] Each pathogenic strain was inoculated into sterile nutrient broth and cultured at 30°C and 200 r / min on a shaker for 24 h. The culture was then centrifuged at 4°C and 8000 r / min for 20 min. After washing twice with sterile saline, the concentration of each pathogenic bacteria suspension was adjusted to 1.0 × 10 10 CFU / mL, stored in a 4℃ refrigerator for later use.

[0033] Isolation and Screening of Thermotolerant Bacillus brevis

[0034] Weigh 1.0 g of shrimp culture mud and suspend it in 9 mL of sterile water. After oscillation and mixing, place it in a 90°C water bath for 10 min. Then, use the dilution plate method to separate and purify the heat-resistant strains on nutrient agar medium. Figure 1 As shown, a heat-resistant strain P2-7 with excellent phagocytic activity was isolated and screened, forming white, wrinkled colonies with irregular edges on nutrient agar plates.

[0035] Heat resistance of thermotolerant Bacillus pumilus

[0036] The concentration was 1.0×10 61 mL of the bacterial liquid of the heat-resistant strain P2-7 with excellent phagocytic activity at CFU / mL was inoculated into 49 mL of sterile nutrient broth, treated in a water bath at 80°C for 20 min, 90°C for 10 min, and 100°C for 5 min, respectively, and then cultured in a shaker at 30°C and 200 r / min for 24 h to observe the growth of the heat-resistant strain P2-7 with excellent phagocytic activity.

[0037] Strain P2-7 was treated in a water bath at 80°C for 20 min, 90°C for 10 min, and 100°C for 5 min, and then cultured in a shaker at 30°C and 200 r / min for 24 h. The culture solution was turbid and the bacteria grew well (as shown in Table 1), indicating that strain P2-7 has good heat resistance.

[0038] Table 1 Growth of strain P2-7 under different heat treatment conditions

[0039] Heat treatment conditions Growth 80℃ water bath treatment for 20min + 90℃ water bath treatment for 10min + 100℃ water bath treatment for 5min +

[0040] Note: + indicates that the culture medium is turbid and the bacteria grow well

[0041] Mode of action of Thermotolerant Bacillus brevis

[0042] The isolated thermotolerant Bacillus pumilus P2-7 colonies were resuspended in sterile saline to a concentration of 1.0×10 6 CFU / mL of bacterial liquid was used, and then the tap water double-layer agar plate method was used to determine the phagocytic activity of the thermotolerant Bacillus brevis strain P2-7 against Pseudomonas aeruginosa FJ1-2, Shewanella salina SFH3, Shigella shigellae BD1, Photobacterium mermanii YJ-1, Acinetobacter venezuelae SHF1, Enterobacter cloacae HT2, Stenotrophomonas maltophilia WY1, and Providencia rettgeri S6. The paper disk method was used to analyze the antagonistic activity of the thermotolerant strain P2-7 with excellent phagocytic activity against Pseudomonas aeruginosa FJ1-2, Shewanella salina SFH3, Shigella shigellae BD1, Photobacterium mermanii YJ-1, Acinetobacter venezuelae SHF1, Enterobacter cloacae HT2, Stenotrophomonas maltophilia WY1, and Providencia rettgeri S6. By observing the formation of phagocytic plaques and inhibition zones, the mode of action of the heat-resistant strain P2-7 with excellent phagocytic activity was determined.

[0043] like Figure 2As shown in the figure, the thermotolerant Bacillus brevis P2-7 has good phagocytic activity against Pseudomonas aeruginosa FJ1-2, Shewanella salinarum SFH3, Oleomonas shigellae BD1, Photobacterium mermanii YJ-1, Acinetobacter venezuelae SHF1, Enterobacter cloacae HT2, Stenotrophomonas maltophilia WY1, and Providencia rettgeri S6, and can form round, clear, smooth, and neatly edged plaques on double-layer agar plates within 24 hours ( Figure 3 ), but could not produce inhibition zones against Pseudomonas aeruginosa FJ1-2, Shewanella algae SFH3, Oleomonas shigelloides BD1, Photobacterium mermanii YJ-1, Acinetobacter venezuelae SHF1, Enterobacter cloacae HT2, Stenotrophomonas maltophilia WY1, and Providencia rettgeri S6, indicating that strain P2-7 did not inhibit bacteria by producing antimicrobial active metabolites, but by phagocytosis.

[0044] Example 2 Identification of Thermotolerant Bacillus brevis

[0045] Molecular identification

[0046] The heat-resistant strain P2-7 with excellent phagocytic activity was inoculated into 100 mL of sterile nutrient broth, and cultured on a shaker at 30°C and 200 r / min for 24 h. The culture was then centrifuged at 4°C and 12,000 r / min for 1 min, the supernatant was discarded, and the genomic DNA was extracted using the Ezup column-type genomic DNA extraction kit (bacteria). The 16S rRNA was amplified by PCR using the genomic DNA as a template.

[0047] The forward primer was 27F: 5'-AGAGTTTGATCCTGGCTCAG-3', and the reverse primer was 1492R: 5'-GGTTACCTTGTTACGACTT-3'; the PCR amplification conditions were: 94℃3min; 94℃1min, 60℃1min, 72℃1min, for a total of 35 cycles. The 16S rRNA gene of the heat-resistant strain P2-7 with excellent phagocytic activity was sequenced by Shanghai Maipu Biotechnology Co., Ltd., and the phylogenetic tree was constructed using the neighbor-joining method using Mega 5.0 software.

[0048] Physiological and biochemical identification

[0049] The Gram-stained heat-resistant strain P2-7 with excellent phagocytic activity was observed for bacterial morphology using an ordinary optical microscope, and then the heat-resistant strain P2-7 with excellent phagocytic activity was physiologically and biochemically identified with reference to the Manual of Identification of Common Bacterial Systems.

[0050] like Figure 4As shown in the figure, the thermotolerant Bacillus pumilus P2-7 is short rod-shaped and Gram-positive. The 16S rRNA gene sequence was compared with the 16S rRNA gene sequences of known strains in the GenBank database. It was found that the 16S rRNA gene sequences of thermotolerant Bacillus pumilus P2-7 and Bacillus pumilus strains were naturally clustered. Then, the phylogenetic tree of strain P2-7 was constructed by the neighbor-joining method ( Figure 5 ) showed that the thermotolerant Bacillus pumilus P2-7 was most closely related to the Bacillus pumilus strain ZBG27 (GenBank accession number: OP223406). In addition, the thermotolerant Bacillus pumilus P2-7 VP reaction was positive, and it could utilize citrate and propionate, and could grow under anaerobic conditions, but it could not utilize nitrates, could not liquefy gelatin, hydrolyze starch, and could not ferment D-xylose, L-arabinose, and D-mannitol, which basically met the physiological and biochemical characteristics of Bacillus pumilus. Therefore, strain P2-7 is Bacillus pumilus, which has been deposited in the Guangdong Provincial Microbiological Culture Collection Center on November 4, 2024, with the deposit number GDMCC NO.65408.

[0051] Example 3 Analysis of the in vitro antibacterial effect of thermotolerant Bacillus pumilus on pathogenic bacteria in artificial simulated aquaculture water

[0052] Before the experiment, the heat-resistant strain P2-7 with excellent phagocytic activity was inoculated into a solid fermentation medium (bran: corn flour: starch: peptone: water = 350:150:1:1:300) at a 30% inoculum. After solid fermentation at 30°C for 5 days, it was dried and ultrafinely ground to produce a bacterial content of 2×10 10 CFU / g of bacterial powder. The in vitro antibacterial effect analysis of thermotolerant Bacillus pumilus P2-7 on pathogenic bacteria in artificial simulated aquaculture water was carried out in a glass conical flask.

[0053] Pseudomonas aeruginosa FJ1-2, Shewanella algae SFH3, Oleomonas shigellae BD1, Photobacterium mermanii YJ-1, Acinetobacter venezuelae SHF1, Enterobacter cloacae HT2, Stenotrophomonas maltophilia WY1, Providencia rettgeri S6 and other pathogenic bacteria were added to 200 mL of filtered aquaculture water treated with autoclave (121°C, 20 min) to a concentration of 5×10 6CFU / mL, and then immediately add the thermotolerant Bacillus pumilus P2-7 powder with a final concentration of 0.4 mg / L. At the same time, filter aquaculture water treated with high pressure sterilization (121°C, 20 min) with only each pathogen added under the same conditions was used as a control. Each treatment was repeated 3 times. After each group was shaken at 30°C and 180 r / min for 5 days, the concentration (CFU / mL) of each pathogen in the aquaculture water was measured. Among them, the concentration of pathogens was determined by the dilution coating TCBS plate method. The inhibition rate was calculated according to formula (1). All data are expressed as mean ± deviation.

[0054] Inhibition rate = {(pathogenic bacteria concentration in control group - pathogenic bacteria concentration in treatment group) / pathogenic bacteria concentration in control group} × 100%… (1)

[0055] like Figure 6 As shown in the results, the thermotolerant Bacillus brevis P2-7 powder has a good inhibitory effect on the growth of Pseudomonas aeruginosa FJ1-2, Shewanella algae SFH3, Shigella-like Pseudomonas BD1, Photobacterium mermanii YJ-1, Acinetobacter venezuelae SHF1, Enterobacter cloacae HT2, Stenotrophomonas maltophilia WY1, and Providencia rettgere S6 in artificial simulated aquaculture water, with the inhibition rates reaching 99.81%, 99.98%, 99.02%, 99.59%, 99.67%, 98.71%, 99.64%, and 95.40%, respectively. This indicates that the thermotolerant Bacillus brevis P2-7 can be used for the ecological control of pathogenic bacteria such as Pseudomonas aeruginosa, Shewanella algae, Shigella-like Pseudomonas, Photobacterium mermanii, Acinetobacter venezuelae, Enterobacter cloacae, Stenotrophomonas maltophilia, and Providencia rettgere in water bodies.

[0056] Example 4 Analysis of the control effect of thermotolerant Bacillus brevis P2-7 on Shewanella disease in white shrimp

[0057] The experiment included 1 negative control group, 1 positive control group and 2 experimental groups, each with three parallel aquariums, and 10L of culture water and 10 white shrimp were added to each aquarium. Thermotolerant Bacillus brevis P2-7 powder was added to the aquarium of the experimental group to 0.4mg / L and 0.8mg / L, and nothing was added to the aquarium of the negative control group. 0.4mg / L of antibacterial Bacillus subtilis (produced by Yurentang Biotechnology (Zhanjiang) Co., Ltd.) was added to the aquarium of the positive control group. Shewanella algae SFH3 was added to the aquariums of the negative control group, the positive control group and the experimental group every day to a final concentration of 5.0×10 6CFU / ml was used for bath infection for 10 consecutive days. During the experiment, the negative control group, positive control group and experimental group were fed with normal feed (purchased from Qingdao Saigelin Feed Co., Ltd.) twice a day (8:00 and 15:00). After the experiment, the morbidity and mortality of white shrimp were observed, the mortality rate was calculated, and the protection rate was calculated according to formula (2). During the experiment, each aquarium was continuously oxygenated and the water temperature was set at 28℃. All data are expressed as mean ± deviation.

[0058] Protection rate = {(mortality rate of negative control group - mortality rate of experimental group) / mortality rate of negative control group} × 100%…(2)

[0059] like Figure 7 As shown, a large number of white shrimps in the negative control group and the positive control group died after the algae shewanella infection, with an average mortality rate of 93.33% and 76.67%, respectively, while the average mortality rate of white shrimps using 0.4mg / L and 0.8mg / L of thermotolerant Bacillus brevis P2-7 powder was significantly reduced, 33.33% and 16.67%, respectively. It was concluded that the protection rates of 0.4mg / L and 0.8mg / L of thermotolerant Bacillus brevis P2-7 powder against shewanella disease in white shrimps were 64.29% and 82.14%, respectively. Therefore, thermotolerant Bacillus brevis P2-7 can be used for the ecological prevention and control of shewanella disease in white shrimps.

[0060] Example 5 Analysis of the application effect of thermotolerant Bacillus pumilus P2-7 in disease prevention and control in shrimp farming production

[0061] The test set up a negative control pool, a positive test pool and a test pool. Each cement pool (30m 2 20,000 whiteleg shrimp fry were released into the pond. The white shrimp in the negative control pool were fed with conventional feed (purchased from Qingdao Saigelin Feed Co., Ltd.), 6 times a day, and the feeding amount was 3% of the total weight of the shrimp. At the same time, potassium persulfate disinfection was used once every half a month; the white shrimp in the positive control pool were fed with feed mixed with antibacterial Bacillus subtilis (produced by Yurentang Biotechnology (Zhanjiang) Co., Ltd.) mixed with a final dose of 20g / kg feed, 6 times a day, and the feeding amount was 3% of the total weight of the shrimp. At the same time, antibacterial Bacillus subtilis (produced by Yurentang Biotechnology (Zhanjiang) Co., Ltd.) was sprayed at a dose of 0.4mg / L every 10d; the white shrimp in the test pool were fed with 20g / kg feed containing thermotolerant Bacillus brevis P2-7 powder, 6 times a day, and the feeding amount was 3% of the total weight of the shrimp. At the same time, the thermotolerant strain P2-7 powder with excellent bacteriophagic activity was sprayed at a dose of 0.4mg / L every 10d. The test period was 90d. During the experiment, the morbidity and mortality of Penaeus vannamei in each pond were observed, and the survival rate was calculated.

[0062] Table 1 Application effect of thermotolerant Bacillus pumilus P2-7 in disease prevention and control of shrimp aquaculture production

[0063]

[0064] Note: + indicates disease occurrence, - indicates no disease occurrence

[0065] As shown in Table 1, the white shrimp in the negative control pool without the use of thermotolerant Bacillus brevis P2-7 powder developed sepsis, acute hepatopancreatic necrosis, white spot syndrome, infectious subcutaneous and hematopoietic necrosis one month after culture, with an incidence and mortality rate of 100%; the positive control group using antibacterial Bacillus subtilis broke out white spot syndrome, infectious subcutaneous and hematopoietic necrosis two months after culture, and the survival rate of the entire test cycle was only 28%; the white shrimp in the test pool using thermotolerant Bacillus brevis P2-7 powder did not develop sepsis, acute hepatopancreatic necrosis, white spot syndrome, infectious subcutaneous and hematopoietic necrosis during the entire culture cycle, and the survival rate of the entire test cycle reached 96%. This shows that thermotolerant Bacillus brevis P2-7 powder can simultaneously prevent the occurrence of sepsis, acute hepatopancreatic necrosis, white spot syndrome, infectious subcutaneous and hematopoietic necrosis in shrimp farming production.

Claims

1. Thermotolerant Bacillus pumilus P2-7, characterized in that It was deposited in Guangdong Provincial Microbiological Culture Collection Center on November 4, 2024, with the deposit number GDMCC NO.65408.

2. The thermotolerant Bacillus pumilus P2-7 according to claim 1, characterized in that Its nucleotide sequence is shown in SEQ ID NO:

1.

3. Use of the thermotolerant Bacillus pumilus P2-7 according to claim 1 in removing / inhibiting pathogenic bacteria in aquaculture water.

4. The use according to claim 3, characterized in that: Thermotolerant Bacillus pumilus P2-7 inhibits bacteria by phagocytosis.

5. The use according to claim 3 or 4, characterized in that: The pathogenic bacteria is selected from at least one of Pseudomonas aeruginosa FJ1-2, Shewanella algae SFH3, Plesiomonas shigelloides BD1, Photobacterium damselae YJ-1, Acinetobacter venetianus SHF1, Enterobacter cloacae HT2, Stenotrophomonas maltophilia WY1, and Providencia rettgeri S6.

6. Use of the thermotolerant Bacillus pumilus P2-7 according to claim 1 in the prevention and control of Shewanella disease in shrimp.

7. The use according to claim 6, characterized in that: The concentration of Shewanella algae SFH3 was 5.0×10 6 CFU / ml, adding 0.8 mg / L of thermotolerant Bacillus brevis P2-7 powder can increase the protection rate of shrimp against Shewanella disease to more than 82%.

8. Use of the thermotolerant Bacillus pumilus P2-7 according to claim 1 in disease prevention and control in shrimp farming production.

9. The use according to claim 8, characterized in that: In shrimp farming, spraying 0.4 mg / L of thermotolerant Bacillus pumilus P2-7 powder and feeding feed containing 20 g / kg of thermotolerant Bacillus pumilus P2-7 powder can prevent the occurrence of sepsis, acute hepatopancreatic necrosis, white spot syndrome, infectious subcutaneous and hematopoietic tissue necrosis.

10. Aquaculture feed, characterized in that: The feed contains the thermotolerant Bacillus pumilus P2-7 according to claim 1 as a feed raw material.

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