A method for degrading toxic and harmful substances in channel catfish breeding pond sediment and inhibiting the proliferation of pathogenic bacteria in the sediment

Abstract

The present invention discloses a method for degrading toxic and harmful substances in the bottom mud of channel catfish breeding ponds and inhibiting the proliferation of pathogenic bacteria in the bottom mud. It belongs to the field of breeding technology. The whole breeding process adopts the technology of precise feeding of biological fermented feed and the technology of replacing antibiotics with inulin, which complement each other. The core is to build a "double-effect" relationship of "probiotics-prebiotics". After use, it can significantly degrade organic matter in the bottom mud, greatly reduce the production of toxic and harmful products such as ammonia nitrogen and the proliferation of pathogenic bacteria such as Proteobacteria. When the above-mentioned technologies are used alone, the effects are not as significant as when they are used simultaneously. At the same time, after tracking for two consecutive breeding cycles, it was found that the output and specifications of channel catfish were significantly improved, and the breeding benefits of fishermen increased significantly.

Description

Technical Field

[0001] The invention relates to the technical field of aquaculture, and more particularly to a method for degrading toxic and harmful substances in bottom mud of channel catfish aquaculture ponds and inhibiting the proliferation of pathogenic bacteria in the bottom mud. Background Art

[0002] In artificial ecosystems such as pond aquaculture, sediment is one of the most active and influential components, and it is closely related to the aquaculture objects and aquaculture water bodies. A large amount of water nutrients are deposited in the sediment of aquaculture ponds, which can buffer the drastic changes in the aquaculture environment and provide a living habitat for microorganisms, zooplankton and benthic animals in the aquaculture ecosystem. Under intensive and high-density aquaculture conditions, the pond aquaculture process is accompanied by continuous input of feed, resulting in a large amount of residual feed and excretion metabolites. In addition, the dead algae in the pond will settle at the bottom of the pond, resulting in the continuous enrichment of nutrients and organic matter in the aquaculture water and sediment, forming a eutrophic aquaculture environment.

[0003] If there is a lack of effective and sustained intervention measures, it will cause serious consequences for aquaculture in the long run, mainly reflected in the following aspects. 1. Formation of a hypoxic environment: The oxidation and decomposition of pond bottom organisms consumes a large amount of oxygen, forming an "oxygen debt", which puts aquatic animals in a hypoxic environment, thereby reducing their physical fitness and their ability to resist diseases; 2. Harmful nutritional indicators are too high: Excessive nutritional surplus plus a hypoxic environment, a large number of facultative anaerobic bacteria decompose organic matter to produce ammonia nitrogen, nitrite, hydrogen sulfide and other large intermediate products, these substances have a strong toxic effect on aquatic animals; 3. Harmful bacteria reproduce rapidly: In this low-oxygen, high-nutrient environment, pathogenic bacteria such as Vibrio are prone to rapid reproduction. When the abundance of pathogenic bacteria reaches the threshold of disease, it is easy to weaken the disease resistance of farmed animals, which can easily lead to pathological changes in aquatic animals and cause disease.

[0004] The channel catfish (Ictalurespunctatus) is native to North America and is a large Siluriformes fish. It was introduced to my country in the 1980s and has successively overcome technical difficulties in breeding, reproduction, feed, processing and export. Because of its tender and delicious meat, lack of intramuscular spines, and strong environmental adaptability, it has become one of my country's important specialty economic fish. In recent years, channel catfish farmed in central my country, in particular, have been harmed by the so-called "overwintering syndrome" in early spring every year. After overwintering, the incidence and mortality rates of channel catfish have increased. According to source tracing, after the temperature rises in spring, the decomposition of excessive organic matter at the bottom of the pond produces a large amount of toxic and harmful products such as ammonia nitrogen, nitrite and hydrogen sulfide. At the same time, the pH value of the water body decreases, providing nutrients for pathogenic bacteria and harmful algae, and also providing a suitable place for plankton and parasites to reproduce. In addition, the decomposition of organic matter and the respiration of oxygen-consuming organisms will greatly increase the oxygen consumption at the bottom of the pond. Relevant data show that the oxygen consumption of the bottom mud of fish ponds is three times higher than that of the bottom mud of fish ponds without fish. These factors are superimposed on each other and have become the main reasons for the increase in the incidence and mortality of channel catfish after the current spring temperature rise.

[0005] In summary, how to provide a technical solution for efficiently degrading toxic and harmful substances in the bottom mud of channel catfish breeding ponds and inhibiting the proliferation of pathogenic bacteria in the bottom mud is a problem that technical personnel in this field urgently need to solve. Summary of the invention

[0006] In view of this, the present invention provides a method for degrading toxic and harmful substances in the bottom mud of channel catfish breeding ponds and inhibiting the proliferation of pathogenic bacteria in the bottom mud.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A method for degrading toxic and harmful substances in the bottom mud of a channel catfish breeding pond and inhibiting the proliferation of pathogenic bacteria in the bottom mud comprises the following steps:

[0009] (1) Precise feeding of biological fermented feed throughout the breeding process:

[0010] (11) During the seedling stage, under normal circumstances, bio-fermented feed is used to replace 30% of the compound feed, mainly to regulate intestinal health and enhance body constitution;

[0011] (12) In the middle and late stages of breeding, under normal circumstances, use bio-fermented feed to replace 10-15% of compound feed;

[0012] In the seedling stage and the middle and late stages of breeding, under special circumstances, the amount of bio-fermented feed should be appropriately increased;

[0013] (13) During the wintering period, use bio-fermented feed to replace 30-50% of compound feed to regulate intestinal health, enhance physical fitness, maintain fat, and alleviate wintering syndrome;

[0014] (14) During the entire breeding process, biological fermentation feed is sprayed throughout the pond 2 to 3 times a month to supplement bacteria and algae, regulate the pH of the water, inhibit the growth and reproduction of harmful bacteria and algae, and stabilize the water quality;

[0015] (2) Inulin replaces antibiotics.

[0016] Beneficial effects achieved: Bio-fermented feed is feed made by microbial fermentation. Microorganisms are added to the basic feed. Through the growth and metabolism of the microorganisms themselves, the toxic substances or anti-nutritional factors in the feed are decomposed and converted into bioactive feed with good palatability, rich nutrition, no toxicity, and high active probiotics. However, according to the feedback from the front-line breeding survey, bio-fermented feed cannot be added and used at will, and it cannot blindly replace the channel catfish compound feed. First, compared with commercial compound feed, bio-fermented feed is not nutritionally comprehensive, and excessive and long-term feeding can easily cause malnutrition of fish; second, because the main acting factors of bio-fermented feed are microorganisms such as lactic acid bacteria and their metabolites contained in it, if it is fed excessively for a long time, it may affect the microecological balance of the pond itself, causing unexpected breeding and ecological risks.

[0017] Inulin is the most widely used prebiotic at present. It can be fermented by microorganisms in the intestine to produce substances such as short-chain fatty acids, which is beneficial to the proliferation of probiotics such as bifidobacteria in the intestine, and inhibits the growth of pathogenic bacteria, which helps to maintain the stability of fish intestinal microorganisms and improve intestinal health. However, there are no reports on the application of inulin in regulating pond sediment microorganisms. The reason why the present invention proposes to use inulin instead of antibiotics is, firstly, to reduce the risk of aquatic product quality and safety caused by drug residues, and secondly, inulin, as a prebiotic, is a natural probiotic growth medium and a natural "growth promoter" for probiotics and their metabolites in biological fermentation feed.

[0018] The seedling period refers to the 2 to 3 months before breeding, and the period from then to the harvest period is the middle and late stages of breeding. The wintering period generally refers to November each year to February of the following year.

[0019] Furthermore, special circumstances refer to situations during the seedling period and the middle and late stages of breeding, high temperature or rainy seasons, excessive feeding amounts or other reasons that may cause fish to develop liver and gallbladder diseases or intestinal discomfort.

[0020] The specific operations in special cases are:

[0021] During the high temperature period or the rainy season, after feeding the compound feed normally, the bio-fermented feed can be used at 30% of the compound feed feeding amount (that is, an additional 30% of the bio-fermented feed is used) to reduce the digestion burden and improve the feed utilization rate.

[0022] When the fish suffer from liver and gallbladder diseases or intestinal discomfort due to excessive feeding or other reasons, using bio-fermented feed to directly replace 30-50% of the compound feed for 3-5 days can reduce the digestive burden, help restore liver and gallbladder function, and reduce the incidence rate.

[0023] Furthermore, the specific operation of step (14) is:

[0024] Add 2-3 catties of bio-fermented feed per mu, 1-2 catties of brown sugar / molasses powder, and water to spray all over the pond; or

[0025] Mix water, biological fermentation feed and brown sugar / molasses powder in a mass ratio of 100:10:5, seal and ferment for 3 to 5 days to obtain fermentation solution, and spray 8 to 10 kilograms of fermentation solution throughout the pond per acre and per meter of water depth.

[0026] Furthermore, the specific operation of step (2) is:

[0027] Accurately weigh inulin according to 1.00-5.00% of the amount of bio-fermented feed fed each time, and then dissolve it in water to obtain inulin liquid, then stir and mix the bio-fermented feed and inulin liquid, blow dry at room temperature, and feed twice a day, with the feeding amount being the same as the feeding amount of bio-fermented feed; or

[0028] After accurately weighing inulin at 5.00-10.00% of the amount of compound feed each time, sprinkle it throughout the pond 30-45 minutes before feeding the biological fermentation feed every day. At the same time, turn on the oxygenator and feed once a day.

[0029] Inulin is only added during the seedling stage, the middle and late stages of breeding, and the wintering period. There is no need to add inulin when spraying biological fermented feed during the entire breeding process.

[0030] Furthermore, the bio-fermented feed is obtained by fermenting corn, soybean meal and bran, inoculating lactic acid bacteria, bacillus and yeast, and the number of live bacteria reaches 10 8 CFU / g.

[0031] The main indicators of the bio-fermented feed are: crude protein (based on dry matter) ≥16%, acid-soluble protein (as a percentage of protein) ≥20%, total acid (based on dry matter) ≥3%, pH ≤4.45, moisture ≤42%, crude ash (based on wet product) ≤8%, and crude fiber (based on wet product) ≤10%.

[0032] Furthermore, the toxic and harmful substances are: organic matter, ammonium nitrogen, total nitrogen, total phosphorus, total potassium, fast-acting phosphorus, and fast-acting potassium.

[0033] Within the carrying capacity of the pond, the existence of these substances is a nutrient for the pond, but once the concentration is too high and exceeds the tolerance of the pond, they will undoubtedly become "toxic and harmful substances". Under the current intensive and high-density breeding conditions, a large amount of feed input, animal feces, leftover bait, and animal decay are deposited to the bottom of the pond, and most of the time they cannot be cleaned up in time. Over time, they will become toxic and harmful substances to the pond ecology.

[0034] Furthermore, the pathogenic bacteria are from the phylum Proteobacteria.

[0035] Through the above technical scheme, it can be known that compared with the prior art, the beneficial effects achieved by the present invention are: the whole breeding process adopts the precise feeding technology of biological fermented feed and the technology of replacing antibiotics with inulin, which complement each other. The core is to build a "double-effect" relationship of "probiotics-prebiotics". After use, it can significantly degrade organic matter in the bottom mud, greatly reduce the production of toxic and harmful products such as ammonia nitrogen and the proliferation of pathogenic bacteria such as Proteobacteria. When the above technologies are used alone, the effects are not as significant as when they are used simultaneously. At the same time, after tracking for two consecutive breeding cycles, it was found that the yield and specifications of channel catfish were significantly improved, and the breeding benefits of fishermen increased significantly. DETAILED DESCRIPTION

[0036] 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 the embodiments. 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.

[0037] The drugs required for the present invention are conventional experimental drugs, which are purchased from commercial channels; the experimental methods not mentioned are conventional experimental methods and will not be described in detail here.

[0038] Example 1

[0039] 1. Experimental Grouping

[0040] The experiment set up 7 groups as follows:

[0041] Control group (fed with compound feed under conventional breeding mode);

[0042] Experimental group 1 (using only biofermented feed);

[0043] Experimental group 2 (inulin only);

[0044] Experimental group 3 (using both biofermented feed and inulin);

[0045] Experimental group 4 (using both biofermented feed and inulin);

[0046] Experimental group 5 (using both biofermented feed and inulin);

[0047] Experimental group 6 (using both biofermented feed and inulin);

[0048] The difference between Experiments 3 to 6 is that the specific usage amounts are different.

[0049] 2. Specific operations

[0050] 1. Conventional breeding mode (control group)

[0051] The protein content of compound feed in the seedling stage (first 2 months) should be above 36%, and the protein content of compound feed in the middle and late stages of breeding (after 2 months) should not be less than 32%. The quality of compound feed must meet the standard of "Safety Limit of Compound Feed" (HY5072-2002). Compound feed is preferably compound pellet feed. The general daily feeding rate is 3% of body weight. The feeding amount of compound feed should be flexibly controlled according to water temperature, water quality, climate change, feeding and other conditions. The feeding amount each time can reach 90% fullness. In summer, feed twice a day, and the interval between the two feedings should be more than 6 hours to facilitate fish digestion of feed. It is best to feed at 9:00 am and 4:00 pm every day. In early spring and autumn, when the water temperature is 15-18℃, feed once a day, with a feeding rate of 1%; when the water temperature is 12-15℃, feed once every other day, with a feeding amount of 1% of the fish body weight; when the water temperature is 7-12℃, feed twice a week, with a feeding rate of 1%. When the water temperature exceeds 32℃ in summer, less feed should be given or no feed should be given.

[0052] 2. Preparation of biological fermentation feed

[0053] The biological fermentation feed of the present invention is prepared by using corn, soybean meal and bran as fermentation substrates, inoculating lactic acid bacteria, bacillus and yeast for fermentation. 8 CFU / g.

[0054] The main indicators of the product: crude protein (based on dry matter) ≥16%, acid-soluble protein (as a percentage of protein) ≥20%, total acid (based on dry matter) ≥3%, pH ≤4.45, moisture ≤42%, crude ash (based on wet product) ≤8%, crude fiber (based on wet product) ≤10%.

[0055] 3. Experimental Group 1

[0056] Precise feeding of biological fermented feed throughout the breeding process:

[0057] (11) During the seedling stage, under normal circumstances, 30% of the compound feed should be replaced by bio-fermented feed;

[0058] (12) In the middle and late stages of breeding, under normal circumstances, use bio-fermented feed to replace 10% of compound feed;

[0059] During high temperature and rainy seasons, after feeding compound feed normally, use 30% of the compound feed amount; when fish have liver and gallbladder diseases or intestinal discomfort, use bio-fermented feed to replace 50% of the compound feed and feed for 5 days;

[0060] (13) During the winter, use bio-fermented feed to replace 30% of the compound feed;

[0061] (14) Add 2 catties of bio-fermented feed per mu to 1 catties of brown sugar / molasses powder and mix with water and sprinkle it all over the pond, 3 times a month.

[0062] 4. Experimental Group 2

[0063] Only inulin replaced antibiotics, that is, the addition of inulin was the same as that of experimental group 4, and no bio-fermented feed was fed.

[0064] Inulin is accurately weighed according to 5.00% of the amount of bio-fermented feed each time and dissolved in water to obtain inulin liquid. The bio-fermented feed and inulin liquid are then stirred and mixed. After drying at room temperature, they are fed twice a day in the same amount as the bio-fermented feed.

[0065] 5. Experimental Group 3

[0066] (1) Precise feeding of biological fermented feed throughout the breeding process:

[0067] (11) During the seedling stage, under normal circumstances, 30% of the compound feed should be replaced by bio-fermented feed;

[0068] (12) In the middle and late stages of breeding, under normal circumstances, use bio-fermented feed to replace 10% of compound feed;

[0069] During high temperature and rainy seasons, after feeding compound feed normally, add bio-fermented feed at 30% of the compound feed amount; when fish have liver and gallbladder diseases or intestinal discomfort, use bio-fermented feed to replace 30% of the compound feed for 3 days;

[0070] (13) During the winter, use bio-fermented feed to replace 30% of the compound feed;

[0071] (14) Add 2 catties of bio-fermented feed per mu to 1 catties of brown sugar / molasses powder and mix with water and sprinkle it all over the pond, twice a month.

[0072] (2) Inulin replaces antibiotics:

[0073] Inulin is accurately weighed according to 1.00% of the amount of bio-fermented feed each time and dissolved in water to obtain inulin liquid. The bio-fermented feed and inulin liquid are then stirred and mixed. After drying at room temperature, they are fed twice a day in the same amount as the bio-fermented feed.

[0074] 6. Experimental Group 4

[0075] (1) Precise feeding of biological fermented feed throughout the breeding process:

[0076] (11) During the seedling stage, under normal circumstances, 30% of the compound feed should be replaced by bio-fermented feed;

[0077] (12) In the middle and late stages of breeding, under normal circumstances, use bio-fermented feed to replace 15% of compound feed;

[0078] During high temperature and rainy seasons, after feeding compound feed normally, add bio-fermented feed at 30% of the compound feed amount; when fish have liver and gallbladder diseases or intestinal discomfort, use bio-fermented feed to replace 50% of the compound feed for 5 days;

[0079] (13) During the winter, use bio-fermented feed to replace 50% of the compound feed;

[0080] (14) Mix water: biological fermentation feed: brown sugar / molasses powder in a ratio of 100:10:5 (m / m), seal and ferment for 3 days to obtain fermentation solution. Sprinkle 8 catties of fermentation solution per acre and per meter of water depth throughout the pond 3 times a month.

[0081] (2) Inulin replaces antibiotics:

[0082] Inulin is accurately weighed according to 5.00% of the amount of bio-fermented feed each time and dissolved in water to obtain inulin liquid. The bio-fermented feed and inulin liquid are then stirred and mixed. After drying at room temperature, they are fed twice a day in the same amount as the bio-fermented feed.

[0083] 7. Experimental Group 5

[0084] (1) Precise feeding of biological fermented feed throughout the breeding process:

[0085] (11) During the seedling stage, under normal circumstances, 30% of the compound feed should be replaced by bio-fermented feed;

[0086] (12) In the middle and late stages of breeding, under normal circumstances, use bio-fermented feed to replace 10% of compound feed;

[0087] During high temperature and rainy seasons, after feeding compound feed normally, add bio-fermented feed at 30% of the compound feed amount; when fish have liver and gallbladder diseases or intestinal discomfort, use bio-fermented feed to replace 30% of the compound feed for 3 days;

[0088] (13) During the winter, use bio-fermented feed to replace 30% of the compound feed;

[0089] (14) Add 3 catties of bio-fermented feed per mu to 2 catties of brown sugar / molasses powder and mix with water and sprinkle it all over the pond, twice a month.

[0090] (2) Inulin replaces antibiotics:

[0091] Inulin is accurately weighed according to 5.00% of the amount of bio-fermented feed each time and dissolved in water to obtain inulin liquid. The bio-fermented feed and inulin liquid are then stirred and mixed. After drying at room temperature, they are fed twice a day in the same amount as the bio-fermented feed.

[0092] 8. Experimental Group 6

[0093] (1) Precise feeding of biological fermented feed throughout the breeding process:

[0094] (11) During the seedling stage, under normal circumstances, 30% of the compound feed should be replaced by bio-fermented feed;

[0095] (12) In the middle and late stages of breeding, under normal circumstances, use bio-fermented feed to replace 15% of compound feed;

[0096] During high temperature and rainy seasons, after feeding compound feed normally, add bio-fermented feed at 30% of the compound feed amount; when fish have liver and gallbladder diseases or intestinal discomfort, use bio-fermented feed to replace 50% of the compound feed for 5 days;

[0097] (13) During the winter, use bio-fermented feed to replace 50% of the compound feed;

[0098] (14) Mix water: biological fermentation feed: brown sugar / molasses powder in a ratio of 100:10:5 (m / m), seal and ferment for 5 days to obtain fermentation solution. Sprinkle 10 catties of fermentation solution per acre and per meter of water depth throughout the pond three times a month.

[0099] (2) Inulin replaces antibiotics:

[0100] Inulin is accurately weighed according to 10.00% of the amount of compound feed fed each time and dissolved in water to obtain inulin liquid. The biological fermentation feed and the inulin liquid are then stirred and mixed. After drying at room temperature, they are fed twice a day in the same amount as the biological fermentation feed.

[0101] 3. Testing indicators

[0102] 1. During the breeding cycle (May 2023-April 2024), the degradation rate of toxic and harmful substances (organic matter, ammonium nitrogen, total nitrogen, total phosphorus, total potassium, available phosphorus, and available potassium) in the sediment.

[0103] Testing methods and standards for each indicator:

[0104] Organic matter shall be in accordance with HJ 615-2011, ammonium nitrogen shall be in accordance with HT 535-2009, total nitrogen shall be in accordance with NY / T53-1987, total phosphorus shall be in accordance with NY / T 88-1988, total potassium shall be in accordance with GB 9836-88, available phosphorus shall be in accordance with HJ 704-2014, and available potassium shall be in accordance with NY / T 889-2004.

[0105] The degradation rate is calculated according to the following method:

[0106] Degradation rate = (initial concentration - final concentration) / initial concentration × 100%.

[0107] 2. After the aquaculture was completed (D360), the sediment was collected, the total DNA of the sediment was extracted, the V3-V4 region of the 16S rRNA gene was amplified, and the diversity and community composition were analyzed.

[0108] 3. Improvement effect on the growth performance, feed utilization, body composition, etc. of channel catfish.

[0109] Including weight gain rate (WGR), feed conversion ratio (FCR), specific growth rate (SGR), survival rate (SR); condition factor (CF), visceral index (VSI), and hepatosomatic index (HSI).

[0110] The calculation formula is as follows:

[0111] (1)WGR=100%×(Wt-W0) / W0;

[0112] (2) FCR = It / (Wt + Wd - W0);

[0113] (3)SGR=100%×(lnWt-lnW0) / t;

[0114] (4) SR = 100% × Nf / Ni;

[0115] (5)CF=Wt / L 3 ×100%;

[0116] (6) VSI = 100% × Wv / W;

[0117] (7) HSI = 100% × Wh / W;

[0118] Wherein, Wt is the final body weight of the fish at the end of the experiment (g); W0 is the initial body weight of the fish (g); It is the total dry weight of the ingested feed (g); t is the number of experimental days (d); Wd is the total death weight (g); Nf is the number of fish at the beginning of the experiment; Ni is the number of fish at the end of the experiment; L is the length of the fish (cm); Wv is the weight of the fish viscera (g); Wh is the weight of the fish liver (g).

[0119] The body composition indicators include moisture, crude protein, crude ash and crude fat, which are determined by the 105℃ drying constant weight method (GB / T6435-1986), the Kjeldahl nitrogen determination method (GB / T 6432-1994), the muffle furnace 550℃ ignition method (GB / T 6438-1992) and the acid hydrolysis crude fat method (GB / T 6433-2006).

[0120] 4. Data on the morbidity and survival rate of channel catfish during the wintering period.

[0121] The incidence rate was calculated as follows:

[0122] Morbidity rate = (number of diseased fish) / (total number of farmed fish) × 100%.

[0123] The survival rate was calculated according to the following method:

[0124] Survival rate = (number of surviving fish at the end of breeding) / (total number of farmed fish) × 100%.

[0125] 5. Data on the production, specifications and increased income of channel catfish during the two breeding cycles (May 2022-April 2023 and May 2023-April 2024).

[0126] IV. Experimental Results

[0127] 1. Degradation effect of toxic and harmful substances in pond sediment

[0128] The degradation effects are shown in Table 1.

[0129] Table 1 Degradation rate of toxic and harmful substances in sediment during the breeding cycle (%)

[0130]

[0131]

[0132] It can be seen from the data in Table 1 that the technical solution of the present invention has a significant reduction effect on the main pollutants in the bottom mud of the breeding pond. Compared with the control group, all indicators in the bottom mud show a faster degradation rate, indicating that after adopting the technical solution of the present invention, in addition to being directly ingested by channel catfish, the probiotics (or metabolites) in the biological fermentation feed that settles to the bottom of the pond can quickly form a dominant population and accelerate the decomposition of organic matter in the bottom mud and the reduction of pollutants. The use of inulin further promotes the proliferation of probiotics and the degradation effect on toxic and harmful substances. When inulin is used alone, the degradation rate of toxic and harmful substances is low, which is significantly lower than that of the other two groups. After using the technical solution of the present invention, it is significantly higher than when biological fermentation feed is used alone or inulin is used alone.

[0133] 2. Inhibitory effect on pathogenic bacteria in pond sediment

[0134] The results are shown in Tables 2 to 3.

[0135] Table 2 shows the changes in the α diversity index of the sediment microbial flora.

[0136] Table 2 Changes in α diversity index of sediment microbial flora (aquaculture D360)

[0137]

[0138] As shown in Table 2, the ACE index and Chao index are used to evaluate the species richness in the sample. As the breeding time progresses, at D360, compared with the control group, the two indexes of experimental groups 3 to 6 (technical solution of the present invention) are significantly higher than those of other groups (P<0.05), indicating that the technical solution of the present invention can significantly improve the richness of the microbial flora. At the same time, there is no significant difference between experimental group 2 (inulin used alone) and the control group (P>0.05), indicating that inulin can only play a synergistic role when used simultaneously with biological fermented feed.

[0139] Shannon index and Simpson index can reflect the uniformity of microbial flora. As the culture time progresses, at D360, compared with the control group, the Shannon index of experimental groups 3 to 6 (technical solution of the present invention) is significantly higher than that of other groups (P<0.05), while the Simpson index is significantly lower than that of other groups (P<0.05), indicating that the use of the technical solution of the present invention can significantly improve the uniformity of microbial flora. At the same time, there is no significant difference between experimental group 2 (inulin used alone) and the control group (P>0.05), indicating that inulin can only play a synergistic role when used together with biological fermented feed.

[0140] Based on the above α diversity index results, the richness and uniformity of the microbial community showed a significant upward trend after the use of the technical solution of the present invention, indicating that the technical solution of the present invention has a good improvement effect on the diversity of sediment microorganisms. At the same time, the effect of using bio-fermented feed and inulin together is significantly better than using them alone.

[0141] The ANOSIM test of bacterial communities showed that there were significant differences in the bacterial community composition among the six groups of aquaculture pond sediment samples (P<0.05). The bacterial community structure of the six groups of aquaculture pond sediment samples was similar at the phylum level, with the highest relative abundance rankings being mainly Proteobacteria, Firmicutes, Bacteroidetes, Chloroflexi, Desulfobacterota, Actinobacteria, Acidobacteriota, Cyanobacteria, Verrucomicrobia, and Spirochaetes.

[0142] The relative abundance of bacterial communities in different groups is shown in the table below.

[0143] Table 3 Relative abundance ratio of microbial flora in different groups at the phylum level (%)

[0144]

[0145] As shown in Table 3, the technical solution of the present invention can significantly increase the abundance of beneficial bacteria Firmicutes, Actinobacteria and Cyanobacteria in the microbial community of the bottom mud of the channel catfish pond, and reduce the relative abundance of conditionally pathogenic bacteria Proteobacteria.

[0146] 3. Improvement effect on the growth performance, feed utilization, body composition, etc. of channel catfish.

[0147] Table 4 Growth, survival rate and feed utilization of channel catfish

[0148]

[0149] As shown in Table 4, after the use of the technical solution of the present invention, compared with the conventional breeding mode and the use of bio-fermented feed and inulin alone, the final body weight, weight gain rate and specific growth rate of channel catfish are significantly improved, the survival rate is more than 90%, and the feed coefficient is the lowest. It is explained that after the compound use of bio-fermented feed and inulin in the present invention, the breeding environment is effectively improved by degrading toxic and harmful substances in the sediment and improving the diversity of sediment microorganisms, thereby promoting the growth of fish, enhancing the stress and disease resistance of fish to the environment, and significantly improving the survival rate. At the same time, without increasing feed input, the feed utilization rate can be improved and the feed coefficient can be reduced.

[0150] Table 5 Effects of body shape indexes (n=10) and body composition (n=6) of channel catfish (%)

[0151]

[0152]

[0153] As shown in Table 5, after the technical solution of the present invention is used, the organ-to-body ratio and liver-to-body ratio of spotted catfish are significantly reduced compared with the conventional breeding mode and when the bio-fermented feed and inulin are used alone, indicating that the combined use of the bio-fermented feed and inulin in the present invention can significantly improve the liver health of the fish; at the same time, the crude protein content is significantly increased, indicating that the nutritional quality of the fish can be improved to a certain extent.

[0154] 4. Data on the morbidity and survival rate of channel catfish during the wintering period.

[0155] Table 6 Incidence and survival rate of channel catfish during wintering (%)

[0156]

[0157] As shown in Table 6, after using the technical solution of the present invention, compared with the conventional breeding mode and the use of biological fermentation feed and inulin alone, the morbidity rate of channel catfish was significantly reduced and the survival rate was significantly improved.

[0158] 5. Data on the production, specifications and increased income of channel catfish during two breeding cycles.

[0159] Table 7 Channel catfish production, specifications and fishermen’s income increase during two breeding cycles

[0160]

[0161] As shown in Table 7, after the technical solution of the present invention is used, compared with the conventional breeding mode and the use of bio-fermented feed and inulin alone, the per-acre yield and specifications of spotted catfish are significantly improved. At the same time, thanks to the significant improvement in yield specifications and survival rate as described in Table 6, the net economic benefits of fishermen are significantly improved.

[0162] Comparative Example 1

[0163] (1) Precise feeding of biological fermented feed throughout the breeding process:

[0164] (11) During the seedling stage, under normal circumstances, bio-fermented feed is used to replace 20% of the compound feed;

[0165] (12) In the middle and late stages of breeding, under normal circumstances, use bio-fermented feed to replace 5% of compound feed;

[0166] During high temperature and rainy seasons, after feeding compound feed normally, add bio-fermented feed at 20% of the compound feed amount; when fish have liver and gallbladder diseases or intestinal discomfort, use bio-fermented feed to replace 20% of the compound feed for 3 days;

[0167] (13) During the winter, use bio-fermented feed to replace 20% of the compound feed;

[0168] (14) Add 2 catties of bio-fermented feed per mu to 1 catties of brown sugar / molasses powder and mix with water and sprinkle it all over the pond, twice a month.

[0169] (2) Inulin replaces antibiotics:

[0170] Inulin is accurately weighed according to 0.05% of the amount of bio-fermented feed each time and dissolved in water to obtain inulin liquid. The bio-fermented feed and inulin liquid are then stirred and mixed. After drying at room temperature, they are fed once a day in the same amount as the bio-fermented feed.

[0171] Comparative Example 2

[0172] (1) Precise feeding of biological fermented feed throughout the breeding process:

[0173] (11) During the seedling stage, under normal circumstances, 40% of the compound feed should be replaced by bio-fermented feed;

[0174] (12) In the middle and late stages of breeding, under normal circumstances, bio-fermented feed is used to replace 20% of compound feed;

[0175] During high temperature and rainy seasons, after feeding compound feed normally, use bio-fermented feed at 40% of the compound feed amount; when fish have liver and gallbladder diseases or intestinal discomfort, use bio-fermented feed to replace 60% of the compound feed for 10 days;

[0176] (13) During the winter, use bio-fermented feed to replace 60% of the compound feed;

[0177] (14) Mix water: biological fermentation feed: brown sugar / molasses powder in a ratio of 100:10:5 (m / m), seal and ferment for 3 days to obtain fermentation solution. Sprinkle 8 catties of fermentation solution per acre and per meter of water depth throughout the pond 3 times a month.

[0178] (2) Inulin replaces antibiotics:

[0179] Inulin is accurately weighed according to 10.00% of the amount of biological fermentation feed fed each time and dissolved in water to obtain inulin liquid. The biological fermentation feed and inulin liquid are then stirred and mixed. After drying at room temperature, they are fed twice a day in the same amount as the biological fermentation feed.

[0180] The results of comparative examples 1 and 2 were compared with the above experimental groups 3 to 6.

[0181] The results are as follows (Table 8 to Table 10):

[0182] Table 8 Degradation rate of toxic and harmful substances in the sediment at the end of aquaculture (D360) (%)

[0183] Group Organic matter Ammonium Nitrogen Total nitrogen Total Phosphorus Total Potassium Fast-acting phosphorus Fast-Acting Potassium Experimental Group 3 59.9 55.8 60.2 56.7 63.5 48.9 35.9 Experimental Group 4 60.5 56.5 61.4 55.8 64.1 50.4 36.8 Experimental Group 5 61.2 55.7 62.1 57.5 64.5 51.3 39.9 Experimental Group 6 62.3 58.1 60.9 59.9 66.5 52.7 40.1 Comparative Example 1 44.3 43.2 39.9 45.5 39.8 32.1 19.7 Comparative Example 2 47.5 41.5 32.4 41.9 35.8 35.6 20.8

[0184] Table 9 Changes in α diversity index of sediment microbial flora at the end of aquaculture (D360)

[0185]

[0186] Table 10 Relative abundance ratio of microbial flora in different groups at the phylum level at the end of culture (D360) (%)

[0187]

[0188] According to the above results, when the method of using bio-fermentation feed or inulin is changed, the degradation rate of toxic and harmful substances in the sediment is significantly lower than that of the technical solution of the present invention (experimental groups 3 to 6), and the improvement of bacterial microbial diversity in the sediment is limited. The abundance-promoting effect on the beneficial bacteria Firmicutes, Actinobacteria and Cyanobacteria in the sediment is significantly weaker. On the contrary, the relative abundance of Proteobacteria, as a typical pathogenic bacteria, is significantly increased.

[0189] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0190] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for degrading toxic and harmful substances in the bottom mud of channel catfish breeding ponds and inhibiting the proliferation of pathogenic bacteria in the bottom mud, characterized in that: The steps include:

1. Accurate feeding of biological fermented feed throughout the breeding process; ① During the seedling stage, under normal circumstances, use bio-fermented feed to replace 30% of the compound feed; ② In the middle and late stages of breeding, under normal circumstances, use bio-fermented feed to replace 10%~15% of compound feed; During the seedling stage and the middle and late stages of breeding, During the high temperature period or the rainy season, after feeding the compound feed normally, the bio-fermented feed can be used at 30% of the compound feed feeding amount; When the amount of feed is too large and causes liver and gallbladder diseases or intestinal discomfort in fish, use bio-fermented feed to replace 30-50% of the compound feed for 3-5 days; ③During the wintering period, use bio-fermented feed to replace 30-50% of compound feed; ④During the whole breeding process, spray the whole pond with biological fermented feed 2 to 3 times a month; 2. Inulin replaces antibiotics; Accurately weigh inulin according to 1.00-5.00% of the amount of bio-fermented feed fed each time, and dissolve it in water to obtain inulin liquid. Then stir and mix the bio-fermented feed and inulin liquid, dry them at room temperature, and feed them twice a day. The feeding amount is the same as that of bio-fermented feed; or Accurately weigh inulin at 5.00~10.00% of the amount of compound feed each time, and sprinkle it throughout the pond 30~45 minutes before feeding the bio-fermentation feed every day. At the same time, turn on the aerator and feed once a day.

2. The method according to claim 1, characterized in that The specific operation of step ④ is: Add 2-3 catties of bio-fermented feed per mu, add 1-2 catties of brown sugar / molasses powder, and water to the whole pond; or Mix water, biological fermentation feed and brown sugar / molasses powder in a mass ratio of 100:10:5, seal and ferment for 3-5 days to obtain fermentation solution, and spray 8-10 jin of fermentation solution throughout the pond per acre and per meter of water depth.

3. The method according to any one of claims 1 to 2, characterized in that: The bio-fermented feed is made of corn, soybean meal and bran as fermentation substrates, inoculated with lactic acid bacteria, bacillus and yeast, and fermented, with the number of live bacteria reaching 10 8 CFU / g.

4. The method according to any one of claims 1 to 2, characterized in that: The toxic and harmful substances are: total nitrogen, total phosphorus and total potassium.

5. The method according to any one of claims 1 to 2, characterized in that: The pathogenic bacteria are from the phylum Proteobacteria.

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