Cetobacterium Soxhlet and application thereof

Abstract

The invention discloses a strain of spermaceti soxhlet ZX 2401Ca, which is preserved in China General Microbiological Culture Collection Center (CGMCC) on January 9, 2025, and the preservation number is CGMCC No.33340. The invention also discloses a method for preparing the spermaceti soxhlet ZX 2401Ca. The cetella sobolifera ZX 2401Ca is indigenous bacteria in the intestinal tract of the snakeheaded fish, and is obtained by screening from the intestinal tract of the snakeheaded fish for the first time. The strain can be metabolized to generate short-chain fatty acid mainly comprising acetic acid, and has very strong oxidation resistance. According to breeding experiments, the inventor finds that the fermented feed prepared from the strain has the functions of improving antioxidant capacity disorder, hepatopancreas injury and the like caused by oxidized fish oil, and also has a good effect in the aspect of improving the aeromonas hydrophila infection resistance of macrobrachium rosenbergii.

Description

Technical Field

[0001] The invention relates to a strain of Cephalosporin and application thereof, belonging to the technical field of microorganisms. Background Art

[0002] Fish oil is rich in highly unsaturated fatty acids and is an essential nutrient in aquatic feed. However, precisely because fish oil is rich in highly unsaturated fatty acids, it is very susceptible to oxidation and rancidity caused by factors such as oxygen, moisture, and light during production, use, and storage, producing a variety of primary and secondary oxides, leading to lipid peroxidation in aquatic animal tissues, reduced antioxidant properties, and adversely affecting the production performance and physiological and biochemical functions of aquatic animals.

[0003] Macrobrachium rosenbergii is one of the important aquaculture species in Jiangsu Province, and its peak production period is from May to August. The high temperature and high humidity climate in Jiangsu Province in summer provides suitable environmental conditions for the oxidation of fish oil, which increases the risk of fish oil oxidation, thereby affecting the health of Macrobrachium rosenbergii and even causing disease outbreaks. It also reduces the quality of Macrobrachium rosenbergii, ultimately affecting production and economic benefits. The problem of oxidative rancidity of feed raw materials affecting the health of aquatic animals has become one of the important issues that cannot be ignored in today's aquaculture industry. Currently, most feed additives used to improve fish oil oxidation are chemical antioxidants, which still have certain problems with fat solubility, stability and safety, and are also relatively expensive. Therefore, providing a safe and effective method to alleviate hepatopancreatic damage to Macrobrachium rosenbergii caused by oil oxidation is a technical problem that urgently needs to be solved in this field.

[0004] Probiotic preparations have been widely used in aquaculture. They can improve the health level and disease resistance of the body by regulating the balance of intestinal flora of aquatic animals and improving the intestinal microecological environment. Probiotic fermented feed is not only an effective means to improve the health and production efficiency of aquatic animals, but also an important strategy to achieve economic and environmental sustainable development. Probiotics in fermented feed can reduce the production of reactive oxygen free radicals and increase the activity of antioxidant enzymes, thereby enhancing the antioxidant capacity of aquatic animals and resisting oxidative stress. At present, there are few types of probiotics used in fermented feed for aquatic animals, mainly concentrated in lactic acid bacteria, Bacillus and yeasts. Most strains are not "indigenous bacteria" from aquatic animals, and their colonization ability and probiotic function in the intestines of aquatic animals are still unstable. Summary of the invention

[0005] The object of the present invention is to solve the above deficiencies and provide a strain of Cetobacterium somerae, which is screened from the intestine of snakehead fish for the first time. It can metabolize to produce short-chain fatty acids mainly acetic acid, has strong antioxidant capacity, can efficiently colonize in the intestine of Macrobrachium rosenbergii, and is used to prepare fermented feed for Macrobrachium rosenbergii, which can effectively enhance the antioxidant capacity and disease resistance of the hepatopancreas of Macrobrachium rosenbergii and improve the hepatopancreas damage caused by oil oxidation.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A strain of Cetobacterium somerae ZX 2401Ca was deposited at the General Microbiological Center of the China Committee for Culture Collection of Microorganisms on January 9, 2025, with the deposit number CGMCC No. 33340. The Cetobacterium somerae ZX 2401Ca is an indigenous bacterium in the intestine of snakehead fish and is screened from the intestine of snakehead fish for the first time. This bacterium can metabolize to produce short-chain fatty acids mainly acetic acid and has strong antioxidant capacity.

[0008] The application of the above Cetobacterium somerae in the preparation of fermented feed for improving the oil oxidation damage of the hepatopancreas of Macrobrachium rosenbergii.

[0009] Furthermore, the preparation method of the fermented feed: mix the Cetobacterium somerae bacterial liquid evenly with the basic compound feed for Macrobrachium rosenbergii, evacuate the air, and ferment anaerobically at 37 °C for 7 days to obtain the fermented feed.

[0010] Furthermore, the formula of the basic compound feed for Macrobrachium rosenbergii: soybean meal 23.00%, fish meal 35.50%, peanut cake 5.00%, chicken meal 2.00%, shrimp paste 2.00%, flour 19.00%, phospholipid powder 1.00%, calcium dihydrogen phosphate 1.50%, fish oil 4.00%, choline chloride 0.25%, vitamin premix 0.20%, mineral premix 0.20%, vitamin C phosphate 0.10%, citric acid 0.05%, guar gum 0.20%, bentonite 4.00%.

[0011] Furthermore, the preparation method of the Bacillus ceti bacterium solution: Pick a single colony of Bacillus ceti and inoculate it into GAM solid medium (peptone 15.0 g / L, tryptone 10.0 g / L, soy peptone 3.0 g / L, yeast extract powder 5.0 g / L, beef powder 2.0 g / L, digested serum powder 13.5 g / L, beef liver extract powder 1.2 g / L, glucose 3.0 g / L, potassium dihydrogen phosphate 2.5 g / L, sodium chloride 3.0 g / L, soluble starch 0.3 g / L, L-cysteine 0.3 g / L, sodium thioglycollate 0.15 g / L, pH 7.2), and anaerobically culture it statically at 37°C for 24 h to obtain the primary seed liquid. Inoculate the primary seed liquid into 200 mL of GAM liquid medium at an inoculation amount of 1%-5% (volume percentage), and anaerobically culture it statically at 37°C for 8-10 h again to obtain the Bacillus ceti bacterium solution.

[0012] Advantages of the present invention:

[0013] The present invention provides a strain of Bacillus ceti ZX 2401Ca, which is first screened from the intestine of snakehead fish. This strain has strong antioxidant ability, can efficiently colonize in the intestine of Macrobrachium rosenbergii, has the potential to be used as an aquatic probiotic, and has a very broad application prospect. The inventor found through breeding experiments that the fermented feed prepared with this strain has functions such as improving the antioxidant capacity disorder and hepatopancreas injury caused by oxidized fish oil, and also has a good effect in improving the ability of Macrobrachium rosenbergii to resist Aeromonas hydrophila infection. Description of the drawings

[0014] Figure 1 It is the colony morphology diagram of Bacillus ceti ZX 2401Ca;

[0015] Figure 2 It is the phylogenetic evolution tree of Bacillus ceti ZX 2401Ca;

[0016] Figure 3 It is the growth curve of Bacillus ceti ZX 2401Ca;

[0017] Figure 4 It is the influence of the fermented feed of Bacillus ceti on the antioxidant enzyme activity of the hepatopancreas of Macrobrachium rosenbergii;

[0018] Figure 5 It is the influence of the fermented feed of Bacillus ceti on the expression level of ferroptosis-related genes in Macrobrachium rosenbergii;

[0019] Figure 6 It is the survival rate test result of Macrobrachium rosenbergii in different treatment groups after being soaked with Aeromonas hydrophila;

[0020] Figure 7 It is the test result of the expression level of immune-related genes in Macrobrachium rosenbergii in different treatment groups after being infected with Aeromonas hydrophila. Detailed implementation manners

[0021] The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments.

[0022] Example 1

[0023] 1. Isolation and identification of Cetobacterium somerae

[0024] The inventors collected the intestinal contents of wild snakehead fish for the isolation and screening of Cetobacterium somerae. The specific method is as follows: The intestinal content sample was placed in a sterilized PBS solution, vortexed evenly, and serially diluted with sterile PBS solution. 100 μL of the mixed solution with an appropriate dilution factor was aspirated and evenly spread on a GAM agar plate. All the above steps were carried out in an anaerobic incubator. The plate was placed in an anaerobic constant temperature incubator and cultured at 37 °C for 48 h. Single colonies suspected to be Cetobacterium somerae were picked and purified. The strain number is ZX 2401Ca.

[0025] The colony characteristics of Cetobacterium somerae ZX 2401Ca on a solid medium are as follows: The colony diameter is 1 - 3 mm, round to irregular in shape, semi-transparent in color, a raised structure with no luster and gray in color. Its colony morphology diagram is as Figure 1 shown, and the optimal growth temperature is 37 °C.

[0026] To further identify the strain, the genomic DNA of the strain was extracted, amplified using the universal primers for 16s rDNA, and the gene sequence of 16s rDNA was obtained by sequencing. Through BLAST analysis on the NCBI website and constructing a phylogenetic evolution tree, as Figure 2 . The results showed that the strain belongs to Cetobacterium somerae in Lactobacillus, named Cetobacterium somerae ZX 2401Ca, and was deposited in the General Microbiology Center of the China Committee for Culture Collection of Microorganisms on January 9, 2025, with the deposit number CGMCC No. 33340.

[0027] 2. Drug sensitivity test of Cetobacterium somerae ZX 2401Ca

[0028] Single colonies of Cetobacterium somerae ZX 2401Ca were picked and inoculated into GAM liquid medium, and anaerobically cultured at 37 °C for 8 - 10 h. 100 μL of the fermentation broth was spread on a GAM agar plate. After the bacterial liquid was absorbed, drug sensitivity test strips were evenly pasted on the petri dish, transferred into an anaerobic chamber, and cultured at 37 °C for 24 h. Then the diameter of the inhibition zone of the drug sensitivity test strip was measured, and its sensitivity was judged according to the standard formulated by the National Committee for Clinical Laboratory Standards (NCCLS) of the United States. The results are shown in Table 1:

[0029] Table 1 Results of drug sensitivity test of Cetobacterium somerae ZX 2401Ca

[0030]

[0031]

[0032] As can be seen from Table 1, Cetobacterium somerae ZX 2401Ca is tolerant to 7 drugs, namely penicillin, oxacillin, erythromycin, gentamicin, streptomycin, vancomycin and lincomycin; moderately sensitive to 18 drugs, namely ampicillin, piperacillin, azithromycin, norfloxacin, ciprofloxacin, cefazolin, ceftazidime, ceftriaxone, cefoperazone, amikacin, kanamycin, tetracycline, polymyxin b, compound sulfamethoxazole, clindamycin, levofloxacin, imipenem and doxycycline; and sensitive to 5 drugs, namely florfenicol, chloramphenicol, cefalexin, cefuroxime sodium and minocycline.

[0033] 3. Analysis of growth performance and acid production ability of Cetobacterium somerae ZX 2401Ca

[0034] Absorb the fermentation broth of Cetobacterium somerae ZX 2401Ca and transfer it to 100 mL of sterile GAM liquid medium at a ratio of 1%, and culture it anaerobically at 37°C. Measure the absorbance value of the fermentation broth at 600 nm every 2 h.

[0035] The growth curve is shown in Figure 3 , and it can be seen from Figure 3 that when inoculated for 1 - 10 h, Cetobacterium somerae ZX 2401Ca enters the logarithmic growth phase, with the fastest growth rate around 6 h and the maximum OD value at 14 h.

[0036] Centrifuge the fermentation broth of Cetobacterium somerae ZX 2401Ca at 10000 r / min for 5 min, collect the supernatant, and ultrafilter to remove bacteria. Use high performance liquid chromatography detection method to quantitatively analyze the short-chain fatty acids in the fermentation supernatant of Cetobacterium somerae. The measurement conditions are as follows: split injection, inject 1 μL, split ratio 10:1. Injection port temperature 250°C; ion source temperature 300°C; transfer line temperature 250°C. The initial temperature of the programmed temperature rise is 90°C; then it is heated to 120°C at a rate of 10°C / min; then it is heated to 150°C at a rate of 5°C / min; finally, it is heated to 250°C at a rate of 25°C / min and maintained for 2 min. The carrier gas is helium, and the carrier gas flow rate is 1.0 mL / min.

[0037] Table 2 Analysis results of short-chain fatty acid production of Cetobacterium somerae ZX-2401Ca

[0038]

[0039]

[0040] 4. Antioxidant Capacity Test of Cetobacterium somerae ZX 2401Ca

[0041] Its antioxidant capacity was verified by the scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. Cetobacterium somerae ZX 2401Ca was inoculated into GAM liquid medium at an inoculation amount of 2%, and incubated at a constant temperature of 37°C in an anaerobic environment for 24 h. Then, it was centrifuged at 4°C and 6000 rpm for 10 minutes, and 1 mL of the supernatant was collected. The supernatant was mixed evenly with 1 mL of 1.50 mmol / L DPPH anhydrous ethanol solution, and reacted in the dark at room temperature for 30 min. The absorbance value was measured at 517 nm. In the blank group, an equal volume of ethanol was used instead of the DPPH solution, in the control group, an equal volume of sterile water was used instead of the fermentation supernatant of Cetobacterium somerae ZX 2401Ca, and 0.125 g / L vitamin C was used as a positive control. The clearance rate calculation formula is as follows:

[0042] Clearance rate / % = [1 - (A 1 - A) / A 0 × 100.

[0043] In the formula, A is the absorbance value of the blank group, A 0 is the absorbance value of the control group, and A 1 is the absorbance value of the sample group.

[0044] The clearance rate of Cetobacterium somerae ZX 2401Ca against DPPH was measured to be 63.23%.

[0045] 5. Bacteriostatic Ability Test of Cetobacterium somerae ZX 2401Ca

[0046] Sterilized medical cotton swabs were used to dip the liquid of Staphylococcus aureus, a common pathogenic bacterium in aquatic products, and evenly spread it on the nutrient agar solid medium. A 1 mL pipette tip (outer diameter: 9 mm) was used to punch holes in the nutrient agar solid medium, and the bottom was sealed with fire. 200 μL of the fermentation broth of Cetobacterium somerae ZX 2401Ca was aspirated and added to the corresponding holes. The petri dish with the added sample was placed in a 4°C refrigerator and left to stand for 2 h, then transferred to a 37°C incubator and anaerobically cultured for 12 h. The diameter of the inhibition zone in the petri dish was measured and recorded to judge the bacteriostatic effect of Cetobacterium somerae ZX 2401Ca.

[0047] The inhibition zone of Cetobacterium somerae ZX 2401Ca against Staphylococcus aureus was measured to be 8.85 mm.

[0048] Example 2

[0049] Cetobacterium somerae Improves the Hepatic Pancreas Injury of Macrobrachium rosenbergii Induced by Oxidized Fish Oil:

[0050] Experimental method: 240 Macrobrachium rosenbergii (3.60 ± 0.10 g) were selected for the experiment and evenly divided into 3 treatment groups, namely the control group (CG), the oxidized fish oil group (OFO), and the oxidized fish oil + Cetobacterium somerae ZX 2401Ca group (OFO + ZX 2401Ca), with 5 replicates in each group and 16 shrimps in each replicate, and cultured for 8 weeks. The daily feeding amount of the experimental shrimps was 5% of their body weight, and they were fed twice a day (06:30 and 18:30).

[0051] The composition of the experimental feed used in each treatment group is shown in Table 3. The fish oil used in the control group (CG) of this experiment was fresh fish oil (peroxide value POV = 6.5 meq / kg); the fresh fish oil was heated and aerated at 65 °C for 5 days for oxidation. During the oxidation period, the oxidized fish oil was collected every day, and the POV was measured every day according to the national standard method (GB / T 5538-2005 / ISO 3960:2001) until its POV reached 307 meq / kg to obtain the oxidized fish oil, which was used to prepare the experimental feed for the OFO and OFO + ZX 2401Ca groups. Before formulating the feed, all raw materials were passed through a 100-mesh sieve, mixed evenly, and made into 1.00-mm pellet feed by a twin-screw extruder, dried at 50 °C, naturally cooled, and then put into a plastic self-sealing bag and stored in a -20 °C refrigerator for later use. Among the three treatment groups, the experimental feed used in the OFO + ZX 2401Ca group was prepared into fermented feed with Cetobacterium somerae bacterium solution. Specifically: 100 μL of Cetobacterium somerae bacterium solution was sucked with a 1-mL syringe and inoculated into GAM liquid medium and cultured at a constant temperature of 37 °C for 14 h, and the bacterium solution concentration was 6.8×10 9 CFU / mL. 30 minutes before feeding, the Cetobacterium somerae bacterium solution was mixed evenly with the Macrobrachium rosenbergii oxidized fish oil compound feed at a ratio of 1:1 (w / w). After vacuum pumping, it was anaerobically fermented at 37 °C for 7 d to obtain fermented feed (the content of Cetobacterium somerae ZX 2401Ca was 1.52×10 7 CFU / g).

[0052] Table 3 Composition of experimental feed (air-dried basis, %)

[0053]

[0054] Note [1] The vitamin premix provided per kilogram of feed: VA, 10000 IU; VD, 2500 IU; VK, 64 mg; VB 2 , 250 mg; VB 1 , 60 mg; folic acid, 12 mg; VB 6 , 60 mg; biotin, 50 mg; calcium pantothenate, 240 mg; VB 12 , 4 mg

[0055] [2]The mineral premix provides per kilogram of feed: Ca(H 2 PO 4 ) 2 , 10 g; MgSO 4 ·7H 2 O, 2.4 g; NaCl, 2.1 g; CuSO 4 ·5H 2 O, 40 mg; KCl, 4.5 g; ZnSO 4 ·H 2 O, 80 mg; FeSO 4 ·H2O, 155 mg; CoCl 2 ·6H 2 O, 4.8 mg; KI, 11.7 mg; MnSO 4 ·H 2 O, 30 mg; Na 2 SeO 3 , 2.4 mg.

[0056] At the end of the breeding experiment, the weight of each individual was measured, and the growth performance was calculated; the hepatopancreas of Macrobrachium rosenbergii was collected to detect the antioxidant enzyme activity and the expression of ferroptosis-related genes.

[0057] (1) Growth performance test

[0058] Before the start of the experiment, the number and weight of Macrobrachium rosenbergii in each culture tank were counted and measured. On the last day of the experiment, after fasting for 24 h, the Macrobrachium rosenbergii in each culture tank were counted and weighed to calculate the survival rate (SR), weight gain rate (WGR), specific growth rate (SGR) and feed conversion ratio (FCR).

[0059] Weight gain rate (%) = (W t - W 0 ) / W 0 × 100

[0060] Specific growth rate (% / d) = (lnW t - lnW 0 ) / T × 100

[0061] Feed conversion ratio = F / (W t – W 0 )

[0062] Hepatopancreas index (%) = W h / W t × 100

[0063] Condition factor (g / cm 3 ) = (W t / L 3 ) × 100

[0064] Where: W t is the weight of the shrimp at the end of the experiment (g); W 0 is the weight of the shrimp at the beginning of the experiment (g); T is the experimental period (d); F is the food intake (g); W h is the weight of the shrimp hepatopancreas (g); L is the body length of the shrimp at the end of the experiment (cm).

[0065] (2) Determination of antioxidant enzyme activity in the hepatopancreas

[0066] The hepatopancreas samples were prepared into homogenates by a high-throughput grinding tissue homogenizer, and the determination of antioxidant enzymes (total antioxidant capacity (T-AOC), superoxide dismutase (SOD), glutathione S-transferase (GST), glutathione peroxidase (GPX), catalase (CAT) and malondialdehyde (MDA) content) was carried out according to the kits of Nanjing Jiancheng Bioengineering Institute Co., Ltd.

[0067] (3) Determination of ferroptosis-related gene expression levels

[0068] Ferroptosis is a newly discovered form of programmed cell death that is distinct from apoptosis, necrosis, and autophagy. Solute carrier family 7 member 11 gene (SLC7A11), the transcriptional repressor p53 of SLC7A11, long-chain acyl-CoA synthetase 4 (ACSL4), and membrane protein transferrin receptor 1 (TFR1) are key factors regulating the occurrence of ferroptosis. The gene expression levels were determined by synthesizing cDNA using TransScript All-in-One First-strand cDNA Synthesis SuperMix for qPCR reagent (Transgen Biotech, Beijing, China). Gene primers were synthesized by Tsingke Biological Company (Beijing, China). The qRT-PCR reaction was carried out on a real-time fluorescence quantitative PCR instrument using ChamQ SYBR qPCR MasterMix (Vazyme, Nanjing, China). The reaction system and conditions were set according to the instructions of the detection kit. The total reaction volume was 20 μL, with β-actin as the internal reference gene, and the method was used to calculate the relative expression levels of gene mRNA.

[0069] Experimental results:

[0070] Table 4 Results of growth performance test

[0071]

[0072] It can be seen from the test results in Table 4 that the final body weight, weight gain rate and specific growth rate of the OFO group were significantly lower than those of the other two groups (P<0.05), and the feed coefficient was the highest (P<0.05). There were no significant differences in the final body weight, weight gain rate, specific growth rate and feed coefficient between the OFO+ZX 2401Ca group and the CG group (P>0.05), indicating that the fermented feed of Cetobacterium somerae can improve the decline in growth performance caused by Macrobrachium rosenbergii feeding on oxidized fish oil feed.

[0073] The non-specific immune system is an important immune mode of Macrobrachium rosenbergii. It scavenges reactive oxygen species in immune cells through antioxidant enzymes (T-AOC, GST, CAT, GPX and SOD), and MDA is also widely used as an index to evaluate oxidative stress. Figure 4 Effects of fermented feed of Cetobacterium somerae on the activities of antioxidant enzymes in the hepatopancreas of Macrobrachium rosenbergii, among which, Figure 4 A is the effect on GST, Figure 4 B is the effect on GPX, Figure 4 C is the effect on MDA, Figure 4 D is the effect on SOD, Figure 4 E is the effect on T-AOC, Figure 4 F is the effect on CAT. It can be seen from the figure that the activities of T-AOC, GST, CAT and GPX in the OFO+ZX 2401Ca group were significantly higher than those in the OFO group, and the MDA content was significantly lower than that in the OFO group (P<0.05), and there were no significant differences from the control group (P>0.05). At the same time, there were no significant differences in the SOD activity between the OFO+ZX2401Ca group and the CG and OFO groups (P>0.05). It shows that the fermented feed of Cetobacterium somerae can improve the decline in antioxidant capacity of Macrobrachium rosenbergii caused by oxidized fish oil.

[0074] Figure 5 Effects of fermented feed of Cetobacterium somerae on the expression levels of ferroptosis-related genes in Macrobrachium rosenbergii, among which, Figure 5 A is the effect on acsl4, Figure 5 B is the effect on tfr1, Figure 5 C is the effect on p53, Figure 5 D is the effect on slc7a11. It can be seen from the figure that after Macrobrachium rosenbergii fed on the fermented feed of Cetobacterium somerae, the expression of ferroptosis-promoting factor genes (acsl4, tfr1, p53) was significantly inhibited (P>0.05), and the expression of ferroptosis-inhibiting factor gene (slc7a11) was increased.

[0075] Example 3

[0076] Fermented feed of Cetobacterium somerae enhances the ability of Macrobrachium rosenbergii to resist Aeromonas hydrophila infection:

[0077] Experimental method: After the aquaculture experiment in Example 1 was completed, 5 shrimps were randomly selected from each treatment group and immersed in Aeromonas hydrophila (1×10 6 CFU / mL) for challenge. The number of dead shrimps was counted at 2h, 4h, 6h, 8h, 12h, and 24h after challenge. The hepatopancreas of the surviving shrimps 24h after challenge was collected for subsequent detection and analysis of immune-related genes (fox, ppar, nf-κb).

[0078] Figure 6 Fig. shows the survival rate test results of Macrobrachium rosenbergii in different treatment groups after being challenged with Aeromonas hydrophila. It can be seen from the figure that the survival rate of Macrobrachium rosenbergii in the OFO group was significantly lower than that of the other two groups at 8 - 24h (P<0.05), and the survival rate of Macrobrachium rosenbergii in the OFO+ZX 2401Ca group was significantly higher than that of the other two groups at 4 - 24h (P<0.05). This indicates that the fermented feed of Cetobacterium somerae can significantly improve the survival rate of Macrobrachium rosenbergii infected with Aeromonas hydrophila.

[0079] Figure 7 Fig. shows the test results of the expression levels of immune-related genes in Macrobrachium rosenbergii in different treatment groups after being infected with Aeromonas hydrophila. Among them Figure 7 A shows the test results of the relative expression level of ppar, Figure 7 B shows the test results of the relative expression level of nf-κb, Figure 7 C shows the test results of the relative expression level of fox. Ppar can inhibit the activity of nf-κb and reduce the expression of pro-inflammatory factors, thereby playing an anti-inflammatory role. The fox gene regulates the development of the immune system, oxidative stress response, apoptosis, etc. It can be seen from the figure that the expression levels of fox and ppar genes in the hepatopancreas of Macrobrachium rosenbergii in the OFO+ZX2401Ca group were significantly higher than those of the other two groups (P<0.05), and the relative expression level of the nf-κb gene was significantly lower than that of the other two groups (P<0.05). This indicates that the fermented feed of Cetobacterium somerae can significantly improve the antioxidant response of Macrobrachium rosenbergii, reduce the expression of pro-inflammatory and apoptotic genes, and reduce the mortality rate of Macrobrachium rosenbergii infected with Aeromonas hydrophila.

[0080] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A strain of Cetobacterium somerae ZX 2401Ca was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration on January 9, 2025, with the deposit number CGMCC No.33340.

2. Use of the Bacillus sorbentii described in claim 1 in the preparation of a fermented feed for improving the oxidative damage of hepatopancreas lipids in Macrobrachium rosenbergii.

3. The use according to claim 2, characterized in that The preparation method of the fermented feed comprises the following steps: uniformly mixing the bacterial liquid of Cephalosporin sorcerini and the basic compound feed of Macrobrachium rosenbergii, vacuumizing the mixture, and performing anaerobically fermentation at 37° C. for 7 days to obtain the fermented feed.

4. The use according to claim 3, characterized in that The formula of the basic compound feed for Macrobrachium rosenbergii is: 23% soybean meal, 35.5% fish meal, 5% peanut cake, 2% chicken meal, 2% shrimp paste, 19% flour, 1% lecithin powder, 1.5% monocalcium phosphate, 4% fish oil, 0.25% choline chloride, 0.2% vitamin premix, 0.2% mineral premix, 0.1% vitamin C phosphate, 0.05% citric acid, 0.2% guar gum and 4% bentonite.

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