Microecological preparation containing bacillus pumilus and application of microecological preparation in aquaculture

Abstract

The invention relates to the technical field of functional microorganism screening and application, and particularly provides a microecological preparation containing bacillus pumilus and application of the microecological preparation in aquaculture. The microecological preparation can significantly promote the growth of aquatic animals, improve the feed utilization rate, enhance the oxidation resistance and organism immunity of the aquatic animals, reduce the occurrence of diseases, reduce tissue loss, significantly improve the apparent digestibility of the aquatic animals, reduce environmental pollution caused by nitrogen and phosphorus emissions, and improve the economic benefits of the aquatic animals. The method can be widely applied to the fields of aquatic feed production.

Description

Technical Field

[0001] The present invention relates to the technical field of functional microorganism screening and application, and in particular to a microecological preparation containing Bacillus pumilus and application thereof in aquaculture. Background Art

[0002] In aquaculture, probiotics have multiple health benefits and play an important role in improving animal productivity, resisting multiple diseases, enhancing immune function, maintaining intestinal health and improving water quality. At the same time, the use of probiotics is in line with the development direction of green ecological aquaculture in the future.

[0003] At present, probiotics are mainly used as feed additives in aquaculture. Probiotics are mixed with animal feed, agricultural and sideline products are processed by probiotic fermentation, or probiotic fermented feed is prepared and finally fed to aquatic animals, which ensures that animals consume probiotics and is widely used. There are also reports showing that probiotics can be directly added to aquaculture water. Probiotics can decompose aquatic animal excrement, residual feed and other debris in the water, effectively reduce the concentration of ammonia nitrogen and nitrite nitrogen in the water, and achieve the purpose of improving water quality and reducing the occurrence of diseases.

[0004] Probiotics can improve the appetite of aquatic animals, thereby increasing their feed intake and promoting their growth. Qian Linjie et al. found that adding 1×10 6 cfu / g Bacillus subtilis and 1×10 6 cfu / g plantarum fed to young bream significantly increased the mass gain rate and specific growth rate of young bream. Zhou et al. found that feeding 1×10 10 cfu / L of Bacillus coagulans B16 as a water additive and feeding it to tilapia significantly increased the final body weight, daily mass gain and specific growth rate of tilapia.

[0005] Probiotics are widely used to enhance the immunity of aquatic animals. 7 cfu / g composite Bacillus spores, fed to grouper, significantly increased the activity of lysozyme and complement C3 in grouper serum, and significantly upregulated the expression of immune genes MHCla, IgM, MHCla and CD8a, thus improving the immunity of grouper. Hoseinifar et al. found that feeding carp with 6×10 7 cfu / g of lactic acid Pediococcus can enhance the immunity of carp by significantly upregulating the expression of lysozyme encoding genes in the fish skin and significantly increasing the content of total immunoglobulin in the skin mucus. Gong et al. found that feeding grass carp 1×10 9 After the infection with Pediococcus pentosaceus at 10 cfu / g, the gene expression levels of IgM and C3 complement proteins in the liver and spleen were increased.

[0006] Probiotics have been shown to be an effective tool for preventing aquaculture diseases. 6 cfu / g and 0.9×10 6 cfu / g of Lactobacillus plantarum significantly improved the resistance of carp to Aeromonas hydrophila. 8 ~4×10 8 cfu / g lactic acid bacteria (Lactobacillus plantarum and Lactobacillus) fed to Penaeus vannamei significantly improved the shrimp's resistance to Vibrio parahaemolyticus.

[0007] The intestine is the main digestive organ of aquatic animals. Eating probiotics can adjust the growth and health of animals by regulating intestinal health. Jiang Xintao et al. found that adding compound probiotic powder (2.5×10 9 cfu / g Bacillus subtilis and 2.0×10 7 cfu / g Lactobacillus acidophilus), can improve the intestinal tissue morphology and digestion and absorption function of hybrid grouper, strengthen the antioxidant capacity of the intestine, increase the relative abundance of intestinal probiotics, enhance the effective utilization of carbon sources by intestinal flora, improve intestinal immune balance, and have a positive effect on the intestinal health of hybrid grouper. Wang Lei's research found that adding 6% compound probiotic solution (concentration of 4.0×10 8 cfu / mL, the main components are Lactobacillus plantarum, Bacillus butyric acid and Bacillus subtilis, etc.), which can increase the diversity of koi intestinal microbial communities and improve intestinal tissue morphology and function.

[0008] Probiotics can improve the water quality of the aquaculture environment. Luo Yuling et al. combined a variety of beneficial live bacteria such as Bacillus subtilis, Bacillus natto, Bacillus licheniformis, and nitrifying bacteria, with a total bacterial count of ≥2.8×10 10 Ind. / g) was added to the pond for crayfish farming experiments. It was found that compared with the control pond, the pond with the addition of complex Bacillus significantly reduced the concentration of ammonia nitrogen and nitrite nitrogen, achieving the purpose of purifying the water.

[0009] Therefore, in recent years, the screening of probiotics has become a research hotspot in this field and is also of great significance to the improvement of aquatic feed formulations. Summary of the invention

[0010] The purpose of the present invention is to provide a microecological preparation containing Bacillus pumilus and its application in aquaculture. The microecological preparation can significantly promote the growth of aquatic animals, enhance their immune function, improve meat quality, and can be widely used in the fields of aquatic feed.

[0011] In one aspect, the present invention provides a probiotic preparation comprising Bacillus pumilus.

[0012] The Bacillus pumilus is Bacillus pumilus CZX17 (Bacillus pumilus CZX17), which was deposited in the China Type Culture Collection of Wuhan University, Wuhan, China on April 29, 2024, and its deposit number is CCTCCNO: M2024808.

[0013] The microecological preparation further comprises an enzyme.

[0014] The enzyme is phytase.

[0015] The microecological preparation also includes Chinese herbal medicine preparations.

[0016] The Chinese herbal medicine preparation consists of bupleurum, kudzu root, hawthorn, liquorice, astragalus and schisandra chinensis.

[0017] The components and their weight proportions in the microecological preparation are: 1-10 parts of Bacillus pumilus CZX17 powder, 1-10 parts of phytase, and 5-15 parts of Chinese herbal medicine preparation; wherein, the components and their weight proportions in the Chinese herbal medicine preparation are: 3-9 parts of bupleurum, 2-10 parts of kudzu root, 2-10 parts of hawthorn, 1-10 parts of liquorice, 3-9 parts of astragalus, and 1-5 parts of schisandra.

[0018] Further preferably, the components and their weight proportions in the microecological preparation are: 3 parts of Bacillus pumilus CZX17 powder, 3 parts of phytase, and 6 parts of Chinese herbal medicine preparation. Among them, the components and their weight proportions in the Chinese herbal medicine preparation are: 5 parts of Bupleurum, 4 parts of Pueraria, 4 parts of Crataegus, 1 part of Licorice, 3 parts of Astragalus, and 1 part of Schisandra.

[0019] The amount of live bacteria in the Bacillus pumilus CZX17 powder is not less than 10 10 CFU / g.

[0020] The present invention also provides application of the microecological preparation in aquatic feed production.

[0021] Beneficial effects of the present invention:

[0022] The microecological preparation containing Bacillus pumilus CZX17 provided by the present invention can significantly promote the growth of aquatic animals, improve feed utilization, enhance the antioxidant capacity and body immunity of aquatic animals, reduce the occurrence of diseases, reduce tissue loss, and at the same time significantly improve the apparent digestibility of aquatic animals and reduce environmental pollution caused by nitrogen and phosphorus emissions.

[0023] Compared with the control group, the weight gain rate and specific growth rate of the experimental group fed with microecological preparations increased by 23.81% and 13.86% respectively; the superoxide dismutase activity, catalase activity, glutathione peroxidase, aspartate aminotransferase and alanine aminotransferase activity in the serum of the experimental group increased by 63.59%, 17.52%, 5.39%, 19.32% and 8.01% respectively, the total antioxidant capacity increased by 15%, and the malondialdehyde concentration decreased by 24.39%; the apparent digestibility of crude protein, crude fat and phosphorus in the experimental group increased by 10.49%, 5.62% and 55.75% respectively, with significant effects. In addition, the total nitrogen emission and total phosphorus emission of the experimental group of largemouth bass decreased by 23.69% and 65.14% respectively, achieving unexpected technical results.

[0024] The microecological preparation provided by the present invention can be widely used in the field of aquaculture, which is beneficial to increasing economic benefits, improving the breeding environment, and has broad prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the colony morphology of Bacillus pumilus CZX17. DETAILED DESCRIPTION

[0026] The equipment and reagents used in the embodiments of the present invention can be selected from any commercially available one. For the specific methods or materials used in the embodiments, those skilled in the art can make conventional replacement selections based on the technical ideas of the present invention and according to existing technologies, and are not limited to the specific records of the embodiments of the present invention.

[0027] The culture medium selected in the embodiment has the following specific formula:

[0028] 2216E culture medium: 5g sodium alginate, 1g glucose, 1g sodium tripolyphosphate, 0.5g magnesium sulfate heptahydrate, 0.1g calcium chloride tetrahydrate, 0.1g ammonium sulfate, 0.01g iron sulfate heptahydrate, 0.01g manganese sulfate heptahydrate, 0.01g zinc sulfate heptahydrate, 0.005g copper sulfate heptahydrate, 0.5g potassium dihydrogen sulfate, 5g peptone, 1000ml distilled water, pH 7.2-7.4, prepare solid culture medium by adding 15-20g agar, and sterilize at 121℃ for 20min.

[0029] LB medium: 10 g tryptone, 5 g yeast extract, 10 g sodium chloride, 15-20 g agar, 1000 mL distilled water, pH 7.4±0.2, autoclave at 121°C for 20 min.

[0030] Nutrient broth medium (1L): 10g peptone, 3g beef extract, 5g sodium chloride. Add the above ingredients to distilled water, make up to 1000mL, heat to dissolve, adjust pH to 7.3±0.2; sterilize at 121℃ for 20min after aliquoting. (Note: solid medium is based on this plus 1.5% agar powder).

[0031] TSB medium: 17g tryptone, 3g soybean papain hydrolysate, 5g sodium chloride, 2.5g glucose monohydrate, 2.5g potassium dihydrogen phosphate, 1000ml distilled water, pH 7.1-7.5. Prepare solid culture medium by adding 13-20g agar and sterilize at 121℃ for 20min.

[0032] Skim milk 2216E solid culture medium: Add 1% skim milk to 2216E culture medium, prepare solid culture medium by adding 1.2%-1.5% agar powder, and sterilize at 121℃ for 20 minutes.

[0033] Potato starch 2216E solid medium: Add 0.3% potato starch to 2216E medium, prepare solid medium by adding 1.2%-1.5% agar powder, and sterilize at 121°C for 20 minutes.

[0034] TW-80 2216E solid culture medium: Add 0.8% TW-80 to 2216E culture medium, prepare solid culture medium by adding 1.2%-1.5% agar powder, and sterilize at 121℃ for 20 minutes.

[0035] The present invention is further described below in conjunction with specific embodiments.

[0036] Example 1 Screening, identification and physiological characteristics analysis of Bacillus pumilus CZX17

[0037] A strain CZX17 with the strongest comprehensive antibacterial ability was screened from the intestines of healthy and vigorous grouper collected from a grouper farm in Hainan Province. The diameters of its inhibition zones against Vibrio harveyi and Vibrio parahaemolyticus reached 2.68 cm and 2.23 cm, respectively.

[0038] The colony morphology of strain CZX17 is shown in Figure 1 The colonies are grayish white, with smooth and neat edges, clear edges, no elongation, and no root-like structures. The surface is sticky and the cells are flat and Gram-positive.

[0039] Through physiological and biochemical identification and 16S rRNA sequence comparison, the strain CZX17 was determined to be Bacillus pumilus, named Bacillus pumilus CZX17, and was deposited in the China Type Culture Collection of Wuhan University, Wuhan, China on April 29, 2024, and its preservation number is CCTCC NO: M2024808.

[0040] The Bacillus pumilus CZX17 can produce a high amount of amylase and protease, and the amylase and protease activities in the fermentation supernatant thereof are as high as 11.23 U / mL and 257 U / mL, respectively.

[0041] The Bacillus pumilus CZX17 can effectively degrade microcystin, and the degradation rates of microcystin at 24h, 48h and 72h are 20.86%, 48.92% and 62.59% respectively, achieving unexpected technical effects.

[0042] Example 2 Antibacterial effect of Bacillus pumilus CZX17 on common pathogenic bacteria

[0043] The fermentation supernatant of Bacillus pumilus CZX17 was filtered through a 0.22 μm microporous filter membrane to obtain a filtrate; the antibacterial ability of the filtrate against 5 bacteria (Streptococcus agalactiae, Pseudomonas, Stenotrophomonas, Citrobacter freundii and Aeromonas hydrophila) was determined by the Oxford cup method. The amount of filtrate added to the Oxford cup was 100 μL. After filling, the culture medium was cultured at 37°C with the front side facing up for 16-18 hours, and the results were observed and the size of the inhibition zone was measured. The results are shown in Table 1.

[0044] Table 1 Antibacterial effect of Bacillus pumilus CZX17 on 5 kinds of bacteria

[0045] Bacterial species Bacillus pumilus inhibition zone diameter (cm) Streptococcus agalactiae 1.61±0.19 Pseudomonas 1.53±0.12 Stenotrophomonas 1.52±0.21 Citrobacter freundii 2.41±0.23 Aeromonas hydrophila 1.52±0.15

[0046] From the results in Table 1, it can be seen that Bacillus pumilus CZX17 has a strong antibacterial effect on five bacteria, including Streptococcus agalactiae, Pseudomonas, Stenotrophomonas, Citrobacter freundii and Aeromonas hydrophila. Among them, the antibacterial effect on Citrobacter freundii is the strongest, with the diameter of the inhibition zone reaching 2.41 cm, achieving unexpected technical results.

[0047] Example 3 Degradation effect of Bacillus pumilus CZX17 on ammonia nitrogen and nitrite nitrogen in aquaculture water

[0048] The Bacillus pumilus CZX17 screened by the present invention is activated and expanded for culture, and then liquid fermentation is performed, and bacterial sludge is collected by centrifugation, a starch carrier is added, and the bacterial powder with a live bacterial count exceeding 10 billion / g is prepared by drying.

[0049] The experimental water was taken from a grouper culture pond in Jiaozhou City, Qingdao. The ammonia nitrogen content in the water was 1.05±0.07 mg / L, and the nitrite nitrogen content was 0.12±0.03 mg / L. The experimental container was a plastic barrel with a volume of 10 L of water.

[0050] Experimental groups:

[0051] (1) Control group: no Bacillus pumilus CZX17 bacterial solution was sprayed;

[0052] (2) Experimental group: Spray Bacillus pumilus CZX17 at a rate of 0.5 g / L.

[0053] 24 hours after spraying the bacterial powder, the water quality was analyzed, and the analysis indicators included pH, ammonia nitrogen and nitrite nitrogen content. The results are shown in Table 2.

[0054] Table 2 Degradation effect of Bacillus pumilus CZX17 on ammonia nitrogen and nitrite nitrogen

[0055] project Control group Experimental Group pH 8.1±0.3 7.9±0.3 Ammonia nitrogen (mg / L) 1.05±0.07 0.026±0.002 Nitrite nitrogen (mg / L) 0.12±0.03 0.008±0.001

[0056] As shown in Table 2, compared with the control group, the pH of the water in the experimental group sprayed with Bacillus pumilus CZX17 powder decreased, and the contents of ammonia nitrogen and nitrite nitrogen decreased by 97.5% and 93.3%, respectively, with a very significant effect. This shows that the Bacillus pumilus CZX17 screened by the present invention can effectively improve water quality and reduce water pollution.

[0057] Example 4 Application of Bacillus pumilus CZX17 in the cultivation of grouper

[0058] 1. Experimental location

[0059] A recirculating aquaculture workshop in Jiaozhou, Qingdao.

[0060] 2. Experimental Grouping

[0061] (1) Control group: fed with basic formula feed;

[0062] (2) Experimental group: 3% Bacillus pumilus CZX17 powder (10 10 CFU / g) of basic formula feed.

[0063] 3. Experimental conditions

[0064] 180 groupers were selected, and three breeding barrels were used as parallel controls in the control group and the experimental group, with 30 groupers in each breeding barrel. Before the formal experiment, they were temporarily raised for 15 days to adapt to the experimental environment. The water temperature of the breeding water was controlled at 25.0±1.0℃, the salinity was 24-26, the ammonia nitrogen concentration was not higher than 0.1mg / L, the nitrite concentration was not higher than 0.05mg / L, the pH was 8.0-8.3, and the dissolved oxygen concentration was 7.0-8.5mg / L. Feed was fed once at 8:30 and 16:30 every day, and the feeding amount was until a little feed was seen, and the residual bait and feces were siphoned off. The experimental feeding cycle was 75d.

[0065] On the 75th day of the experiment, the weight and length of the fish in each group were weighed, and the growth rate, specific growth rate, feed coefficient and survival rate were calculated. The experimental grouper was deprived of food for 24 hours and anesthetized with 40 mg / L eugenol. When sampling, 1 mL of medical syringe was rinsed with 1% sodium heparin, and venous blood was drawn from the fish. The blood was centrifuged at 3000 rpm for 10 min at 4 °C, and the supernatant was aspirated for the determination of blood indicators. The grouper was dissected, and about 1.0 g of liver tissue was cut and stored at -20 °C for the determination of liver enzyme activity, total antioxidant capacity, and malondialdehyde concentration.

[0066] 4. Experimental results

[0067] (1) Growth performance analysis

[0068] Table 3 Growth performance parameters of grouper after 75 days of feeding

[0069] Group Control group Experimental Group Initial weight(g) 92.11±6.51 92.18±7.64 Final weight (g) <![CDATA[147.52±7.44 a ]]> <![CDATA[156.26±8.76 b ]]> growth rate(%) <![CDATA[60.16±6.06 a ]]> <![CDATA[69.65±5.88 b ]]> Specific growth rate (%) <![CDATA[0.61±0.05 a ]]> <![CDATA[0.70±0.05 b ]]> Feed coefficient 2.56±0.37 2.35±0.16 Survival rate (%) 100 100

[0070] Note: Data in the same column with different letters indicate significant differences (P<0.05), while data with the same letters or no letters indicate no significant differences (P>0.05).

[0071] As shown in Table 3, compared with the control group, the growth rate and specific growth rate of the grouper fed with Bacillus pumilus CZX1 powder increased by 15.77% and 14.75% respectively, and the feed coefficient decreased by 8.2%. This shows that the Bacillus pumilus CZX17 provided by the present invention can effectively promote the growth of farmed animals and improve feed utilization, with a very significant effect.

[0072] (2) Plasma biochemical and immune indicators

[0073] ROCHE p800 fully automatic biochemical analyzer (Germany) was used to detect plasma biochemical indicators, including total protein, blood glucose, triglyceride concentration and alkaline phosphatase activity. The mass concentrations of plasma complement C3 and C4 were determined according to the instructions of the corresponding kit (purchased from Nanjing Jiancheng Bioengineering Institute). The experimental results are shown in Table 4.

[0074] Table 4 Effects of Bacillus pumilus CZX17 on plasma biochemical and immune parameters of Orientia truncatula

[0075]

[0076] Note: Data in the same column with different letters indicate significant differences (P<0.05), while data with the same letters or no letters indicate no significant differences (P>0.05).

[0077] As can be seen from Table 4, compared with the control group, the concentrations of blood glucose and triglyceride in the plasma of the experimental group of grouper fed with Bacillus pumilus CZX17 powder decreased by 14.22% and 11.52%, respectively, and the alkaline phosphatase activity increased by 15.93%, with significant effects. The results of immune indexes showed that the mass concentration of complement C3 in the plasma of the grouper in the experimental group was significantly higher than that in the control group, increasing by 36.84%, indicating that the Bacillus pumilus CZX17 provided by the present invention can significantly improve the immunity of grouper.

[0078] (3) Liver antioxidant index

[0079] The liver superoxide dismutase activity, catalase activity, peroxidase activity, glutathione reductase activity, glutathione peroxidase activity, total antioxidant capacity and malondialdehyde concentration were determined according to the instructions of the antioxidant enzyme detection kit (purchased from Nanjing Jiancheng Bioengineering Institute). The results are shown in Table 5.

[0080] Table 5 Effects of Bacillus pumilus CZX17 on antioxidant capacity of grouper liver

[0081]

[0082] Note: Data in the same column with different letters indicate significant differences (P<0.05), while data with the same letters or no letters indicate no significant differences (P>0.05).

[0083] As shown in Table 5, compared with the control group, the total antioxidant capacity of the group of grouper fed with Bacillus pumilus CZX17 powder increased by 14.08% (P<0.05), the superoxide dismutase activity, catalase activity, peroxidase activity and glutathione reductase activity in serum increased by 20.16%, 21.23%, 22.59% and 88.24% respectively; the molar concentration of malondialdehyde decreased by 20.18% (P<0.05), and the effect was very significant. It is thus shown that the Bacillus pumilus CZX17 provided by the present invention can significantly improve the antioxidant capacity and active oxygen scavenging ability of grouper, thereby helping to reduce the accumulation of lipid peroxides and reduce tissue loss.

[0084] Example 6 A microecological preparation

[0085] A microecological preparation, wherein the components and their weight proportions are: 1 part of Bacillus pumilus CZX17 powder, 1 part of phytase, and 5 parts of Chinese herbal medicine preparation; wherein the components and their weight proportions in the Chinese herbal medicine preparation are: 3 parts of bupleurum, 2 parts of kudzu root, 2 parts of hawthorn, 1 part of liquorice, 3 parts of astragalus, and 1 part of schisandra.

[0086] Example 7 A microecological preparation

[0087] A microecological preparation, wherein the components and their weight proportions are: 2 parts of Bacillus pumilus CZX17 powder, 2 parts of phytase, and 5.5 parts of Chinese herbal medicine preparation; wherein the components and their weight proportions in the Chinese herbal medicine preparation are: 3 parts of bupleurum, 5 parts of kudzu root, 5 parts of hawthorn, 1 part of liquorice, 3 parts of astragalus, and 1 part of schisandra.

[0088] Example 8 A microecological preparation

[0089] A microecological preparation, wherein the components and their weight proportions are respectively: 3 parts of Bacillus pumilus CZX17 powder, 3 parts of phytase, and 6 parts of Chinese herbal medicine preparation; wherein the components and their weight proportions in the Chinese herbal medicine preparation are respectively 5 parts of bupleurum, 4 parts of kudzu root, 4 parts of hawthorn, 1 part of liquorice, 3 parts of astragalus, and 1 part of schisandra.

[0090] Example 9 Application of microecological preparations in largemouth bass breeding

[0091] 1. Experimental location

[0092] Inside a recirculating aquaculture workshop in Qingdao.

[0093] 2. Experimental Grouping

[0094] (1) Control group: ordinary feed with basic nutritional level;

[0095] (2) Experimental group: The microecological preparation described in Example 8 was added to ordinary feed at a ratio of 30 kg / ton.

[0096] 3. Experimental conditions

[0097] 180 largemouth bass were selected. Three aquariums were used as parallel control groups for the control group and the experimental group, respectively, with 30 largemouth bass in each aquarium. Before the formal experiment, they were temporarily cultured for 15 days to adapt to the experimental environment. The culture water temperature was 23-25℃, ammonia nitrogen in the water was <0.01mg / L, dissolved oxygen was >6.5mg / L, pH was 7.0-7.4, and the booster pump was aerated for 24 hours. The sewage was drained and the water was changed regularly every day, and the water change volume was 1 / 3. The culture cycle lasted for 60 days, and the fish were fed twice a day (8:30 and 17:00) at regular intervals. After feeding for 0.5 hours, the bottom was sucked to remove the residual bait, and the residual bait was placed in a drying box, dried at 65℃, weighed and recorded. After the end of the experiment, the weight of the residual bait was subtracted when calculating the total food intake.

[0098] During the breeding experiment, feces were collected every day by siphoning method, 3 h after each feeding, and then placed in an oven for drying at 65 °C and stored at -20 °C for testing. Feces were collected until the end of the breeding experiment.

[0099] On the 60th day of the experiment, the experimental largemouth bass were starved for 24 hours, and the number of live fish and the total amount of feed in each aquarium were counted. Ten fish were randomly selected from each aquarium, treated with the anesthetic MS-222, and the surface moisture of the fish was blotted with gauze before weighing and measuring body length and other indicators; blood collected from the tail vein was centrifuged at 4000r / min at 4℃ for 10min to prepare serum samples, which were stored in a -80℃ refrigerator for the determination of serum biochemical and antioxidant indicators; the fish bodies were dissected, and the parameters such as the content of relevant nutrients in the fish bodies were determined using the national standard method, and the total nitrogen and total phosphorus emissions of largemouth bass were calculated.

[0100] 4. Experimental results

[0101] (1) Growth performance

[0102] Table 6 Effects of probiotics on growth performance of largemouth bass

[0103]

[0104] Note: Data in the same column with different letters indicate significant differences (P<0.05), while data with the same letters or no letters indicate no significant differences (P>0.05).

[0105] As shown in Table 6, compared with the control group, the weight gain rate of the largemouth bass in the experimental group fed with the microecological preparation increased by 23.81%, and the specific growth rate increased by 13.86%. This shows that the microecological preparation provided by the present invention can significantly promote the growth of aquatic animals, reduce the feed conversion rate, and improve the utilization rate of feed.

[0106] (2) Serum biochemical indicators and antioxidant capacity

[0107] The Nanjing Jiancheng kit was used to detect serum alanine aminotransferase activity, aspartate aminotransferase activity, glutathione peroxidase activity, superoxide dismutase activity, catalase activity, total antioxidant capacity and malondialdehyde concentration. Details are shown in Table 7.

[0108] Table 7 Effects of probiotics on serum biochemical parameters and antioxidant capacity of largemouth bass

[0109]

[0110] As shown in Table 7, compared with the control group, the superoxide dismutase activity, catalase activity, glutathione peroxidase, aspartate aminotransferase and alanine aminotransferase activities in the serum of largemouth bass fed with the microecological preparation increased by 63.59%, 17.52%, 5.39%, 19.32% and 8.01% respectively; the total antioxidant capacity increased by 15%, and the malondialdehyde concentration decreased by 24.39%, which was very significant. It can be seen that the microecological preparation provided by the present invention can effectively enhance the antioxidant capacity and immunity of aquatic animals, reduce the accumulation of lipid peroxides, and reduce tissue loss.

[0111] (3) Apparent digestibility of nutrients

[0112] Table 8 Effects of probiotics on apparent digestibility of nutrients in largemouth bass

[0113]

[0114]

[0115] As shown in Table 8, compared with the control group, the apparent digestibility of crude protein, crude fat and phosphorus in the experimental group fed with probiotics increased by 10.49%, 5.62% and 55.75% respectively (p < 0.05), with significant effects.

[0116] (4) Total nitrogen emissions and total phosphorus emissions

[0117] Table 9 Effects of microecological preparations on total nitrogen and total phosphorus emissions of largemouth bass

[0118] project Total nitrogen emissions (g / kg) Total phosphorus emission (g / kg) Control group <![CDATA[57.42±1.92 a ]]> <![CDATA[9.58±0.45 a ]]> Experimental Group <![CDATA[43.82±4.65 b ]]> <![CDATA[3.34±0.22 b ]]>

[0119] As shown in Table 9, compared with the control group, the total nitrogen emissions and total phosphorus emissions of largemouth bass in the experimental group fed with microecological preparations were reduced by 23.69% and 65.14%, respectively, achieving unexpected technical results.

[0120] In summary, the microecological preparation containing Bacillus pumilus CZX17 provided by the present invention can be widely used in aquatic feed, can significantly promote the growth of aquatic animals, reduce the feed coefficient, improve their utilization rate of feed, enhance the antioxidant capacity and immunity of aquatic animals, reduce the occurrence of diseases, reduce tissue loss, and at the same time can significantly improve the apparent digestibility of aquatic animals, reduce environmental pollution caused by nitrogen and phosphorus emissions, and has broad application prospects.

Claims

1. A microecological preparation, characterized in that: The microecological preparation comprises Bacillus pumilus ( Bacillus pumilus ).

2. The microecological preparation according to claim 1, characterized in that: The deposit number of the Bacillus pumilus is CCTCCNO: M2024808.

3. The microecological preparation according to claim 2, characterized in that: The microecological preparation further comprises an enzyme.

4. The microecological preparation according to claim 3, characterized in that: The enzyme is phytase.

5. The microecological preparation according to claim 3 or 4, characterized in that: The microecological preparation also includes Chinese herbal medicine preparation.

6. The microecological preparation according to claim 5, characterized in that: The Chinese herbal medicine preparation consists of bupleurum, kudzu root, hawthorn, liquorice, astragalus and schisandra chinensis.

7. The microecological preparation according to claim 6, characterized in that: The components and their weight proportions in the microecological preparation are: 1-10 parts of Bacillus pumilus powder, 1-10 parts of phytase, and 5-15 parts of Chinese herbal medicine preparation; wherein, the components and their weight proportions in the Chinese herbal medicine preparation are: 3-9 parts of bupleurum, 2-10 parts of kudzu root, 2-10 parts of hawthorn, 1-10 parts of liquorice, 3-9 parts of astragalus, and 1-5 parts of schisandra.

8. The microecological preparation according to claim 7, characterized in that: The components and their weight proportions in the microecological preparation are: 3 parts of Bacillus pumilus powder, 3 parts of phytase, and 6 parts of Chinese herbal medicine preparation; wherein, the components and their weight proportions in the Chinese herbal medicine preparation are: 5 parts of bupleurum, 4 parts of kudzu root, 4 parts of hawthorn, 1 part of licorice, 3 parts of astragalus, and 1 part of schisandra.

9. The probiotic preparation according to any one of claims 1 to 8, characterized in that: The amount of live Bacillus pumilus in the microecological preparation is not less than 10 10 CFU / g.

10. Use of the probiotic preparation according to any one of claims 1 to 8 in aquatic feed production.

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