Multi-nutrition-level ecological breeding method for freshwater fish

Abstract

The invention discloses a multi-nutrition-level ecological breeding method for freshwater fishes. The method comprises the following steps: (1) plane partition construction and restoration of a breeding system; (2) pond pretreatment; (3) putting basic filter-feeding fishes and shellfishes; (4) putting main fish culture classes; (5) breeding process management and micro-ecological regulation and control; and (6) catching finished fish in batches. According to the multi-nutrition-level ecological breeding method, the water surface of a pond is physically separated, spatial separation and graded purification of breeding pollutants are achieved, meanwhile, control of filter-feeding fishes on suspended organic matter and absorption of submerged plants and clams on soluble nutritive salt are synergistically utilized, and the ecological breeding efficiency is improved. And the functional compound microecological preparation can degrade the substrate and water pollutants in situ, so that the disease occurrence rate and the dependence on an exogenous water body are reduced while the rapid and healthy growth of the main fish culture is guaranteed, and good ecological and economic benefits are achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ecological breeding, and particularly relates to a multi-nutrient level ecological breeding method of freshwater fish. BACKGROUND

[0002] Freshwater fish farming is an important part of China's aquaculture industry. The traditional freshwater fish farming mode mainly relies on the natural productivity of natural water areas, and the mode is relatively extensive. With the increasing demand for aquatic products in the market and the continuous improvement of consumers' quality requirements, the high-density and intensive farming mode aiming at high yield has gradually become the mainstream.

[0003] However, the high-density and intensive farming mode not only brings significant yield increase, but also causes a series of technical bottlenecks restricting its sustainable development. First, a large amount of high-protein compound feed is not completely ingested and absorbed by fish during the breeding process, and together with the feces excreted by fish, a large amount of residual feed and excrement accumulates at the bottom of the pond. These organic wastes continuously release high concentrations of toxic and harmful substances such as ammonia nitrogen and nitrite into the water under the decomposition of microorganisms, leading to water eutrophication, excessive algae reproduction, reduced water transparency, and dramatic diurnal fluctuations in dissolved oxygen. The deterioration of water quality not only directly threatens the health of farmed fish, increases the risk of stress and disease outbreaks, but also requires frequent water changes during the middle and late stages of breeding, which not only increases water consumption and production costs, but also causes pollution pressure on the external water environment.

[0004] Secondly, the deterioration of pond bottom is another prominent problem in intensive farming. The accumulation and corruption of a large amount of organic matter in the pond bottom forms an anaerobic environment. In this environment, anaerobic microorganisms such as sulfate-reducing bacteria are abnormally active, reducing sulfate to hydrogen sulfide, which is highly toxic and corrosive. The presence of hydrogen sulfide not only directly poisons the respiratory system of fish, causing chronic poisoning or even acute death, but also combines with metal ions in the bottom mud to form black sulfide, causing the bottom to turn black and emit a foul odor, which seriously damages the ecological system stability of the breeding water area and is an important reason for unstable yield in the middle and late stages of breeding.

[0005] In order to overcome the above-mentioned deficiencies, the existing technology usually adopts various means for improvement. In the aspect of breeding mode, pond engineering circulating water breeding technology has been developed, which intensifies water flow through oxygenation and water pushing equipment, and concentrates the treatment of pollutants, but this mode usually has high energy consumption, and the treatment of pollutants is still not thorough. In the aspect of water quality regulation, the method of adding microbial preparations is generally used to decompose organic pollutants and nitrogen-containing compounds in the water body by using beneficial bacteria (such as Bacillus, nitrifying bacteria, etc.). In the aspect of bottom improvement, chemical oxygenating agents (such as calcium peroxide) or adsorbents (such as zeolite powder, activated carbon) are mainly relied on to passively improve the oxidation-reduction potential of the bottom mud or adsorb part of the pollutants.

[0006] While the aforementioned existing technologies have alleviated problems in the aquaculture process to some extent, they still have significant technical shortcomings. Firstly, traditional microbial preparations have limited functions and lack synergistic effects among various strains. They typically only target one type of pollutant (such as ammonia nitrogen or organic matter), making it difficult to simultaneously address the complex situation of multiple pollutants such as nitrogen, sulfur, and organic matter coexisting in the aquaculture environment. This results in limited purification efficiency and an inability to form a complete pollution degradation chain. Secondly, commercially available microbial products are mostly simple powders or liquids, easily diluted and lost after being added to water. Furthermore, microorganisms directly exposed to the aquaculture environment are susceptible to adverse factors such as pH, temperature, and predators, leading to low survival and colonization rates, resulting in unstable effects and short durations of action. Thirdly, existing sediment conditioners are mostly passive treatments. For example, chemical oxygenators have short-lived effects and only address the symptoms, not the root cause; physical adsorbents merely transfer pollutants without truly removing them from the ecosystem, and there is a risk of secondary release after saturation. They cannot fundamentally solve the problems of organic pollution accumulation and continuous endogenous sulfide production in the sediment.

[0007] Therefore, developing a comprehensive technical solution that can systematically, efficiently, and sustainably address the combined pollution of water and sediment in high-density aquaculture has become an urgent technical challenge in this field. Summary of the Invention

[0008] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a multi-trophic-level ecological aquaculture method for freshwater fish.

[0009] To achieve the above objectives, the present invention provides the following technical solution: A multi-trophic-level ecological aquaculture method for freshwater fish includes the following steps: (1) Planar partitioning and repair of the aquaculture system: The pond water surface is divided into three independent functional areas from the inlet to the outlet using a permeable mesh, namely the main aquaculture area, the filter feeding and purification area and the deep purification area. Submerged plants are planted at the bottom of the deep purification area, and microporous oxygenation facilities and air-lift water-pushing devices are installed. (2) Pond pretreatment: Before filling the pond, the bottom of the pond is dredged and exposed to the sun, and quicklime is sprinkled throughout the pond for disinfection; after filling the pond to 0.8-1.0m, tea seed cake is used to kill wild fish; after the effects of the medicine have disappeared, fermented organic fertilizer is applied, and then the water is replenished to 1.5-2.0m. (3) Release basic filter-feeding fish and shellfish: When the water transparency of the pond reaches 30-40cm, release silver carp and bighead carp in the filter-feeding purification zone, and release triangular sail mussels or pleated crown mussels in the deep purification zone by hanging. (4) Stocking the main fish species: When the water temperature is stable above 15℃, stock the main culture area with California bass fry; (5) Management and microecological regulation of aquaculture process: Feed high-protein extruded compound feed to California bass in the main aquaculture area. The daily feeding amount is 2%-4% of the body weight of the fish in the pond. Turn on the air lift water push device to maintain the water body circulating in the direction of main aquaculture area → filter feeding purification area → deep purification area → main aquaculture area. Every 7-10 days, add functional compound microecological agents to the sewage collection point of the main aquaculture area and the connecting channel between the main aquaculture area and the filter feeding purification area. The dosage is 0.15-0.3 kg / mu. (6) Harvest the finished fish in batches.

[0010] Preferably, in step (1), the water area of ​​the main aquaculture zone is 20-25%, the water area of ​​the filter feeding and purification zone is 45-50%, and the water area of ​​the deep purification zone is 25-30%; the submerged plant is Vallisneria natans or Hydrilla verticillata.

[0011] In this invention, the fishpond is divided into three functional zones: the main breeding zone is mainly responsible for high-density aquaculture and collection of uneaten feed and feces, and a sludge collection pit is provided at the bottom; the filter feeding and purification zone is mainly responsible for the biotransformation of phytoplankton and suspended particulate matter; and the deep purification zone is mainly responsible for the adsorption of dissolved phosphorus and the filtration of fine particles.

[0012] Preferably, in step (2), the fermented organic fertilizer is fermented and decomposed chicken manure or pig manure, and the application rate is 100-150 kg / mu.

[0013] In this invention, dredging and sun exposure are used to remove excess organic matter and pathogens left over from the previous aquaculture. Quicklime has the dual function of disinfection and pH adjustment of the bottom mud. Tea seed cake is a natural and biodegradable pond-cleaning agent used to kill wild fish carrying pathogens. The purpose of applying fermented organic fertilizer is to cultivate algae and provide basic natural food for filter-feeding fish and shellfish that are subsequently introduced.

[0014] Preferably, in step (3), the stocking density of silver carp is 150-200 fish / mu, and the size is 100-200g / fish; the stocking density of bighead carp is 80-100 fish / mu, and the size is 200-500g / fish; the stocking density of triangular sail mussel or pleated crown mussel is 800-1000 mu, and the hanging depth is 0.5-1.5m underwater.

[0015] In this invention, when the water body has a basic fertility level, a biological purification unit is introduced. Silver carp and bighead carp are typical filter-feeding fish that feed on phytoplankton and zooplankton, respectively. They are key biological weapons for controlling the excessive proliferation of algae in the water body and preventing algal blooms. Triangular sail mussels or pleated crown mussels are filter-feeding mollusks that can efficiently filter out suspended particles, organic debris and microalgae in the water, which has a remarkable effect on improving water transparency and reducing organic load.

[0016] Preferably, in step (4), the stocking density of the California bass fry is 2,500-3,000 fish / acre, and the size is 10-15cm / fish; before stocking, the fish need to be disinfected by soaking in 3%-4% saline solution for 5-10 minutes.

[0017] Preferably, in step (5), the preparation method of the functionalized compound microecological preparation is as follows: S1. Disperse zeolite powder in ferrous sulfate solution and stir for 30-40 minutes under nitrogen atmosphere. Then, add sodium sulfide solution dropwise under stirring conditions and carry out the stirring reaction. After the reaction is completed, filter, wash and dry to obtain composite zeolite powder. S2. Add the composite zeolite powder to an ethanol aqueous solution, then add γ-glycidyl etheroxypropyltrimethoxysilane and carry out a constant temperature reaction. After the reaction is completed, filter, wash, and dry to obtain pretreated zeolite powder. Add the pretreated zeolite powder to deionized water, then add γ-aminobutyric acid, taurine, and triethylamine and carry out a heating reaction. After the reaction is completed, filter, wash, and dry to obtain modified zeolite powder. S3. A compound bacterial solution is prepared by mixing Bacillus laterosporus, nitrifying bacteria, denitrifying bacteria and sulfur-oxidizing bacteria. Modified zeolite powder is then added to the compound bacterial solution and shaken for adsorption. After adsorption is completed, the solution is filtered. The solid product and trehalose are added to an aqueous solution of sodium alginate and stirred to form a suspension. The suspension is then added dropwise to an aqueous solution of calcium chloride, allowed to stand and solidify, filtered, washed and freeze-dried under vacuum to obtain the functionalized compound microecological preparation.

[0018] Preferably, in step S1, the concentration of the ferrous sulfate solution is 0.3-0.5 mol / L, the concentration of the sodium sulfide solution is 0.3-0.5 mol / L, the mass-to-volume ratio of the zeolite powder, ferrous sulfate solution, and sodium sulfide solution is 1 g: 10-20 mL: 15-25 mL, the stirring reaction temperature is 20-30℃, and the time is 1-2 h; the volume ratio of ethanol to water in the ethanol-water solution is 8-9:1-2, the mass ratio of the composite zeolite powder to γ-glycidoxypropyltrimethoxysilane is 100:6-10, and the isothermal reaction temperature is 60-70℃, and the time is 4-6 h.

[0019] In this invention, zeolite powder is used as the base carrier. Zeolite is a natural porous aluminosilicate mineral with a large specific surface area and good adsorption performance, providing a site for subsequent reactions and initially adsorbing pollutants such as ammonia nitrogen. FeS nanocrystals are generated in situ using a solution-precipitation method. The core function of FeS is to chemically fix hydrogen sulfide, converting highly toxic soluble gas into a stable solid substance. The resulting composite zeolite powder is uniformly loaded with FeS nanocrystals, which can improve the efficacy of functionalized composite microecological agents in removing sulfides from water. Subsequently, it reacts with γ-glycidyl etheroxypropyltrimethoxysilane to introduce highly active epoxy groups onto the composite zeolite powder, providing reaction sites for subsequent reactions.

[0020] Preferably, in step S2, the volume ratio of ethanol to water in the ethanol-water solution is 8-9:1-2, the mass ratio of the composite zeolite powder to γ-glycidyl etheroxypropyltrimethoxysilane is 100:6-10, the isothermal reaction temperature is 60-70℃, and the time is 4-6h; the mass ratio of the pretreated zeolite powder, γ-aminobutyric acid, taurine, and triethylamine is 100:1.2-2:1.8-3:1.5-2.5, and the heating reaction temperature is 50-60℃, and the time is 12-16h.

[0021] In this invention, molecules with bioregulatory functions (γ-aminobutyric acid and taurine) are introduced onto a composite carrier through a ring-opening reaction, endowing the formulation with value-added functions that directly affect farmed animals, in addition to environmental remediation. The γ-aminobutyric acid and taurine molecules are linked to the carrier surface through stable covalent bonds, which is fundamentally different from simple physical adsorption. The covalent bond connection ensures that these functional molecules are not easily eluted, but are slowly released as the carrier degrades or under the action of specific enzymes, thus achieving long-term efficacy.

[0022] Preferably, in step S3, the ratio of Bacillus laterosporus, nitrifying bacteria, denitrifying bacteria, and sulfur-oxidizing bacteria in the compound bacterial solution is 2-3:2-3:1-2:1-2, and the total viable count is ≥6×10⁻⁶. 9 The mass-to-volume ratio of the modified zeolite powder to the composite bacterial solution is 1 g: 10-20 mL; the temperature for the shaking adsorption is 30-35℃, and the time is 2-4 h; the mass concentration of the sodium alginate aqueous solution is 1.5-2.5%; the mass ratio of the solid product, trehalose, and sodium alginate aqueous solution is 10:1-2:80-100; the mass concentration of the calcium chloride aqueous solution is 2-4%; and the time for static solidification is 30-60 min.

[0023] In this invention, a specific ratio of liquid composite microbial flora is efficiently, densely, and actively solidified into stable granules for easy storage, transportation, and precise application, ensuring its survival and effectiveness even in harsh pond bottom environments. Lateral spores of Bacillus, nitrifying bacteria, denitrifying bacteria, and sulfur-oxidizing bacteria are mixed in a specific ratio to form a functionally complementary composite microbial agent. The modified zeolite powder's large specific surface area, abundant porous structure, and surface-grafted organic functional groups provide numerous attachment points and shelters for microorganisms. Carrier particles carrying the microbial cells are suspended in a sodium alginate solution. Then, calcium chloride solution is added to form core-shell structured gel spheres, which are then freeze-dried under vacuum. The water is sublimated directly under low temperature and low pressure, maximizing the preservation of microbial activity. The resulting functionalized microecological compound preparation has an outermost sodium alginate gel that can resist external environmental impacts, an inner zeolite carrier that provides physical protection for microorganisms, and trehalose that ensures the survival rate of bacteria during dormancy and revival. When added to water, the particles slowly dissolve and degrade, gradually releasing highly active beneficial bacteria and functionalized carriers, achieving the ultimate goal of long-term sustained release and targeted purification.

[0024] Preferably, in step (6), the specific method for harvesting finished fish in batches is as follows: in the middle and late stages of aquaculture, when the individual size of California bass in the main aquaculture area reaches the commercial size, the method of catching the big ones and leaving the small ones, and rotating the harvesting and releasing is adopted for batch harvesting; when the filter-feeding fish in the filter-feeding purification area reach the commercial size or the biomass exceeds the environmental carrying capacity, timely harvesting is carried out; at the same time, the growth status of shellfish is monitored regularly, and when they reach the commercial size, they are harvested and restocked.

[0025] Compared with the prior art, the present invention has the following beneficial effects: (1) The multi-trophic-level ecological aquaculture method for freshwater fish provided by the present invention physically divides the pond surface into a main culture area, a filter-feeding purification area and a deep purification area, and constructs a directional water circulation model to achieve spatial separation and graded purification of aquaculture pollutants. The method synergistically utilizes the control of suspended organic matter by filter-feeding fish, the absorption of soluble nutrients by submerged plants and mussels, and the in-situ degradation of bottom sediment and water pollutants by functionalized compound microecological agents to form an efficient, stable and low-emission ecological aquaculture closed-loop system. This system significantly improves the utilization efficiency of water resources and the carrying capacity of the aquaculture system. While ensuring the rapid and healthy growth of the main cultured fish, it reduces the incidence of diseases and dependence on external water sources, and has good ecological and economic benefits.

[0026] (2) The multi-trophic-level ecological aquaculture method for freshwater fish provided by the present invention adds functionalized compound microecological agents, which, by loading ferrous sulfide on the surface of zeolite powder in situ, endow the carrier with the innovative function of actively regulating the sulfur cycle in the aquaculture environment. The FeS generated in situ can not only directly fix the highly toxic hydrogen sulfide in the water and bottom sediment through chemical reaction, eliminating its acute or chronic toxicity to farmed animals, but also serve as an electron donor to provide a continuous energy source for sulfur-oxidizing bacteria in the compound microbial community, thereby enhancing the bioconversion efficiency of sulfides. Through the dual action mechanism of chemical fixation and biocatalysis, the problem of traditional microbial agents being unable to eradicate sulfide pollution is solved, fundamentally improving the pond bottom sediment environment and preventing the bottom mud from turning black and smelly. (3) This invention uses γ-glycidyl etheroxypropyltrimethoxysilane as a bridge to covalently graft γ-aminobutyric acid and taurine onto composite zeolite powder, forming a multifunctional carrier with both environmental remediation and biostimulation functions. γ-aminobutyric acid and taurine, as important neurotransmitters and osmotic pressure regulators, can be slowly released through water, effectively alleviating the stress response of fish under high-density aquaculture conditions and enhancing their immunity and disease resistance. This functionalized composite microecological preparation integrates the functions of environmental improvement materials and animal nutrition and health products. While purifying water quality, it can directly produce positive physiological regulation effects on farmed animals, thereby improving aquaculture efficiency.

[0027] (4) The compound bacteria added to the functionalized compound microecological preparation of the present invention are scientifically compounded with Bacillus laterosporus responsible for degrading macromolecular organic matter, nitrifying bacteria that convert ammonia nitrogen to nitrate, denitrifying bacteria that remove nitrogen from nitrate, and sulfur oxidizing bacteria responsible for removing sulfides. The decomposition products of Bacillus laterosporus can provide carbon sources for denitrification and other processes, while the dominant strains of sulfur oxidizing bacteria can simultaneously utilize nitrate for denitrification and sulfur oxidation, thus closely combining the two major cycles of nitrogen and sulfur. This bacterial community structure ensures the formation of a complete degradation chain for various pollutants such as residual feed, feces, ammonia nitrogen, nitrite, nitrate, and sulfides, significantly improving the overall removal efficiency of pollutants and the stability of the system.

[0028] (5) In the process of preparing functionalized compound microecological preparations, the present invention first adsorbs the compound microbial community onto the surface of the functionalized carrier, and then uses the sodium alginate-calcium chloride system for overall encapsulation. This core-shell immobilization structure improves the initial loading density of the microbial strains through the porosity and surface charge of the carrier. On the other hand, the external sodium alginate gel layer plays a physical protection and slow-release role, effectively protecting the internal microorganisms from the damage caused by pH and temperature fluctuations and predatory organisms in the aquaculture environment. It significantly improves the survival rate, colonization efficiency and duration of action of beneficial bacteria in the harsh pond bottom environment, and ensures the stability of the product's effect in actual application. Attached Figure Description

[0029] Fig. 1 A comparison chart showing the changes in ammonia nitrogen concentration in water bodies over time; Fig. 2 This is a comparison chart showing the change of COD concentration in water over time. Detailed Implementation

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

[0031] Unless otherwise specified, all chemical reagents and materials in this invention are purchased from the market or synthesized from raw materials purchased from the market.

[0032] The Bacillus laterosporus was Bacillus laterosporus CCTCC CB 20082249, purchased from the China Center for Type Culture Collection. The denitrifying bacteria was *Pseudomonas putida* ACCC 01017, purchased from the China Agricultural Microbial Culture Collection Center (ACCC), strain number 01017; The nitrifying bacteria was Vibrio Fisherii CICC 10483, purchased from the China Industrial Microbial Culture Collection Center (CICC), with the strain preservation number 10483; The sulfur-oxidizing bacteria was Thiobacillus denitrificationus ATCC25259, purchased from the ATCC Culture Collection Center.

[0033] Example 1 A multi-trophic-level ecological aquaculture method for freshwater fish includes the following steps: (1) Planar partitioning and repair of the aquaculture system: The pond water surface is divided into three independent functional areas from the inlet to the outlet using a permeable mesh, namely the main aquaculture area, the filter feeding purification area and the deep purification area. The main aquaculture area occupies 20-25% of the water area, the filter feeding purification area occupies 45-50% of the water area and the deep purification area occupies 25-30% of the water area. Vallisneria natans or Hydrilla verticillata are planted at the bottom of the deep purification area, and microporous oxygenation facilities and air-lift water-pushing devices are installed. (2) Pond pretreatment: Before filling the pond, the bottom of the pond is dredged and exposed to the sun. Quicklime is used to disinfect the whole pond. After filling the pond to 0.8-1.0m, tea seed cake is used to kill wild fish. After the drug has worn off, fermented and decomposed chicken manure or pig manure is applied at a rate of 130kg / mu. Then the water is replenished to 1.5-2.0m. (3) Stocking basic filter-feeding fish and shellfish: When the water transparency of the pond reaches 30-40cm, silver carp and bighead carp are stocked in the filter-feeding purification zone. The stocking density of silver carp is 180 fish / mu, and the size is 100-200g / fish. The stocking density of bighead carp is 90 fish / mu, and the size is 200-500g / fish. Triangular sail mussels are stocked in the deep purification zone by suspension. The stocking density is 900 mu, and the suspension depth is 0.5-1.5m underwater. (4) Stocking the main fish species: When the water temperature is stable above 15℃, stock California bass fry in the main breeding area. The stocking density of California bass fry is 2800 fish / acre, and the size is 10-15cm / fish. Before stocking, the fish should be disinfected by soaking in 3% saline solution for 10 minutes. (5) Management and microecological regulation of aquaculture process: Feed high-protein extruded compound feed to California bass in the main aquaculture area. The daily feeding amount is 3% of the body weight of the fish in the pond. Turn on the air lift water push device to maintain the water body in the direction of main aquaculture area → filter feeding purification area → deep purification area → main aquaculture area. Every 8 days, add functional compound microecological preparations to the sewage collection point of the main aquaculture area and the connecting channel between the main aquaculture area and the filter feeding purification area. The amount added is 0.25 kg / mu. (6) Harvesting adult fish in batches: In the middle and late stages of aquaculture, when the size of the California bass in the main aquaculture area reaches the commercial size, the large ones are caught and the small ones are left to grow, and the fish are harvested in batches by rotation. When the filter-feeding fish in the filter-feeding purification area reach the commercial size or the biomass exceeds the environmental carrying capacity, timely harvesting is carried out. At the same time, the growth status of shellfish is monitored regularly, and when they reach the commercial size, they are harvested and restocked.

[0034] In step (5), the preparation method of the functionalized compound microecological preparation is as follows: S1. Disperse 100g of zeolite powder in 1.5L of 0.4mol / L ferrous sulfate solution and stir for 35min under nitrogen atmosphere. Then, add 2L of 0.4mol / L sodium sulfide solution dropwise under stirring and stir at 25℃ for 1.5h. After the reaction is completed, filter, wash and dry to obtain composite zeolite powder. S2. Add 100g of composite zeolite powder to 1L of ethanol-water solution (ethanol to water volume ratio of 8.5:1.5), then add 8g of γ-glycidyl etheroxypropyltrimethoxysilane, and react at 65℃ for 5h. After the reaction is complete, filter, wash, and dry to obtain pretreated zeolite powder. Add 100g of pretreated zeolite powder to 1L of deionized water, then add 1.6g of γ-aminobutyric acid, 2.5g of taurine, and 2g of triethylamine, and react at 55℃ for 14h. After the reaction is complete, filter, wash, and dry to obtain modified zeolite powder. S3. Mix 25g of Bacillus laterosporus, 25g of nitrifying bacteria, 15g of denitrifying bacteria and 15g of sulfur-oxidizing bacteria to prepare a compound bacterial solution (total viable count ≥ 6 × 10⁻⁶). 9 (cfu / mL), then 100g of modified zeolite powder was added to 1.5L of the compound bacterial solution, and the mixture was shaken and adsorbed at 33℃ for 3h. After adsorption was completed, the mixture was filtered, and 100g of solid product and 15g of trehalose were added to 900g of sodium alginate aqueous solution with a mass concentration of 2%, and stirred to form a suspension. Then the suspension was added dropwise to calcium chloride aqueous solution with a mass concentration of 3%, and allowed to stand for 50min to solidify. After filtration, washing, and vacuum freeze-drying, the functionalized compound microecological preparation was obtained.

[0035] Example 2 A multi-trophic-level ecological aquaculture method for freshwater fish includes the following steps: (1) Planar partitioning and repair of the aquaculture system: The pond water surface is divided into three independent functional areas from the inlet to the outlet using a permeable mesh, namely the main aquaculture area, the filter feeding purification area and the deep purification area. The main aquaculture area occupies 20-25% of the water area, the filter feeding purification area occupies 45-50% of the water area and the deep purification area occupies 25-30% of the water area. Vallisneria natans or Hydrilla verticillata are planted at the bottom of the deep purification area, and microporous oxygenation facilities and air-lift water-pushing devices are installed. (2) Pond pretreatment: Before filling the pond, the bottom of the pond is dredged and exposed to the sun. Quicklime is used to disinfect the whole pond. After filling the pond to 0.8-1.0m, tea seed cake is used to kill wild fish. After the drug effect disappears, fermented and decomposed chicken manure or pig manure is applied at a rate of 100kg / mu. Then, the water is replenished to 1.5-2.0m. (3) Stocking basic filter-feeding fish and shellfish: When the water transparency of the pond reaches 30-40cm, silver carp and bighead carp are stocked in the filter-feeding purification zone. The stocking density of silver carp is 150 fish / mu, and the size is 100-200g / fish. The stocking density of bighead carp is 80 fish / mu, and the size is 200-500g / fish. In the deep purification zone, pleated crown mussels are stocked by suspension at a density of 800 mu and a suspension depth of 0.5-1.5m underwater. (4) Stocking the main fish species: When the water temperature is stable above 15℃, stock California bass fry in the main breeding area. The stocking density of California bass fry is 2,500 fish / acre, and the size is 10-15cm / fish. Before stocking, the fish should be disinfected by soaking in 3% saline solution for 10 minutes. (5) Management and microecological regulation of aquaculture process: Feed high-protein extruded compound feed to California bass in the main aquaculture area. The daily feeding amount is 2% of the body weight of the fish in the pond. Turn on the air lift water push device to maintain the water body in the direction of main aquaculture area → filter feeding purification area → deep purification area → main aquaculture area. Every 8 days, add functional compound microecological preparations to the sewage collection point of the main aquaculture area and the connecting channel between the main aquaculture area and the filter feeding purification area. The amount added is 0.3 kg / mu. (6) Harvesting adult fish in batches: In the middle and late stages of aquaculture, when the size of the California bass in the main aquaculture area reaches the commercial size, the large ones are caught and the small ones are left to grow, and the fish are harvested in batches by rotation. When the filter-feeding fish in the filter-feeding purification area reach the commercial size or the biomass exceeds the environmental carrying capacity, timely harvesting is carried out. At the same time, the growth status of shellfish is monitored regularly, and when they reach the commercial size, they are harvested and restocked.

[0036] In step (5), the preparation method of the functionalized compound microecological preparation is as follows: S1. Disperse 100g of zeolite powder in 1L of 0.5mol / L ferrous sulfate solution and stir for 30min under nitrogen atmosphere. Then, add 1.5L of 0.5mol / L sodium sulfide solution dropwise under stirring. Stir and react at 20℃ for 2h. After the reaction is complete, filter, wash and dry to obtain composite zeolite powder. S2. Add 100g of composite zeolite powder to 1L of ethanol-water solution (ethanol to water volume ratio of 8:2), then add 5g of γ-glycidyl etheroxypropyltrimethoxysilane, and react at 60℃ for 6h. After the reaction is complete, filter, wash, and dry to obtain pretreated zeolite powder. Add 100g of pretreated zeolite powder to 1L of deionized water, then add 1.2g of γ-aminobutyric acid, 1.8g of taurine, and 1.5g of triethylamine, and react at 50℃ for 16h. After the reaction is complete, filter, wash, and dry to obtain modified zeolite powder. S3. Mix 20g of Bacillus laterosporus, 20g of nitrifying bacteria, 10g of denitrifying bacteria and 10g of sulfur-oxidizing bacteria to prepare a compound bacterial solution (total viable count ≥ 6 × 10⁻⁶). 9 (cfu / mL), then 100g of modified zeolite powder was added to 1L of the composite bacterial solution, and the mixture was shaken and adsorbed at 30℃ for 4h. After adsorption was completed, the mixture was filtered, and 100g of solid product and 10g of trehalose were added to 800g of sodium alginate aqueous solution with a mass concentration of 1.5% and stirred to form a suspension. Then the suspension was added dropwise to calcium chloride aqueous solution with a mass concentration of 2% and allowed to stand for 30min to solidify. After filtration, washing, and vacuum freeze-drying, the functionalized composite microecological preparation was obtained.

[0037] Example 3 A multi-trophic-level ecological aquaculture method for freshwater fish includes the following steps: (1) Planar partitioning and repair of the aquaculture system: The pond water surface is divided into three independent functional areas from the inlet to the outlet using a permeable mesh, namely the main aquaculture area, the filter feeding purification area and the deep purification area. The main aquaculture area occupies 20-25% of the water area, the filter feeding purification area occupies 45-50% of the water area and the deep purification area occupies 25-30% of the water area. Vallisneria natans or Hydrilla verticillata are planted at the bottom of the deep purification area, and microporous oxygenation facilities and air-lift water-pushing devices are installed. (2) Pond pretreatment: Before filling the pond, the bottom of the pond is dredged and exposed to the sun. Quicklime is used to disinfect the whole pond. After filling the pond to 0.8-1.0m, tea seed cake is used to kill wild fish. After the drug has worn off, fermented and decomposed chicken manure or pig manure is applied at a rate of 150kg / mu. Then the water is replenished to 1.5-2.0m. (3) Stocking basic filter-feeding fish and shellfish: When the water transparency of the pond reaches 30-40cm, silver carp and bighead carp are stocked in the filter-feeding purification zone. The stocking density of silver carp is 200 fish / mu, and the size is 100-200g / fish. The stocking density of bighead carp is 100 fish / mu, and the size is 200-500g / fish. Triangular sail mussels are stocked in the deep purification zone by suspension. The stocking density is 1000 mu, and the suspension depth is 0.5-1.5m underwater. (4) Stocking the main fish species: When the water temperature is stable above 15℃, stock California bass fry in the main breeding area. The stocking density of California bass fry is 3000 fish / acre, and the size is 10-15cm / fish. Before stocking, the fish should be disinfected by soaking in 3% saline solution for 10 minutes. (5) Management of aquaculture process and regulation of microecology: Feed high-protein extruded compound feed to California bass in the main aquaculture area. The daily feeding amount is 4% of the body weight of the fish in the pond. Turn on the air lift water push device to maintain the water body in the direction of main aquaculture area → filter feeding purification area → deep purification area → main aquaculture area. Every 8 days, add functional compound microecological preparations to the sewage collection point of the main aquaculture area and the connecting channel between the main aquaculture area and the filter feeding purification area. The amount added is 0.15 kg / mu. (6) Harvesting adult fish in batches: In the middle and late stages of aquaculture, when the size of the California bass in the main aquaculture area reaches the commercial size, the large ones are caught and the small ones are left to grow, and the fish are harvested in batches by rotation. When the filter-feeding fish in the filter-feeding purification area reach the commercial size or the biomass exceeds the environmental carrying capacity, timely harvesting is carried out. At the same time, the growth status of shellfish is monitored regularly, and when they reach the commercial size, they are harvested and restocked.

[0038] In step (5), the preparation method of the functionalized compound microecological preparation is as follows: S1. Disperse 100g of zeolite powder in 2L of 0.3mol / L ferrous sulfate solution and stir for 40min under nitrogen atmosphere. Then, add 2.5L of 0.3mol / L sodium sulfide solution dropwise under stirring and stir at 30℃ for 1h. After the reaction is complete, filter, wash and dry to obtain composite zeolite powder. S2. Add 100g of composite zeolite powder to 1L of ethanol-water solution (ethanol to water volume ratio of 9:1), then add 10g of γ-glycidyl etheroxypropyltrimethoxysilane, and react at 70℃ for 4h. After the reaction is complete, filter, wash, and dry to obtain pretreated zeolite powder. Add 100g of pretreated zeolite powder to 1L of deionized water, then add 2g of γ-aminobutyric acid, 3g of taurine, and 2.5g of triethylamine, and react at 60℃ for 12h. After the reaction is complete, filter, wash, and dry to obtain modified zeolite powder. S3. Mix 30g of Bacillus laterosporus, 30g of nitrifying bacteria, 20g of denitrifying bacteria and 20g of sulfur-oxidizing bacteria to prepare a compound bacterial solution (total viable count ≥ 6 × 10⁻⁶). 9 (cfu / mL), then 100g of modified zeolite powder was added to 2L of the compound bacterial solution, and the mixture was shaken and adsorbed at 35℃ for 2h. After adsorption was completed, the mixture was filtered, and 100g of solid product and 20g of trehalose were added to 1000g of sodium alginate aqueous solution with a mass concentration of 2.5% and stirred to form a suspension. Then the suspension was added dropwise to calcium chloride aqueous solution with a mass concentration of 4%, allowed to stand and solidify for 60min, filtered, washed, and vacuum freeze-dried to obtain the functionalized compound microecological preparation.

[0039] Comparative Example 1 A multi-trophic-level ecological aquaculture method for freshwater fish includes the following steps: (1) Planar partitioning and repair of the aquaculture system: The pond water surface is divided into three independent functional areas from the inlet to the outlet using a permeable mesh, namely the main aquaculture area, the filter feeding purification area and the deep purification area. The main aquaculture area occupies 20-25% of the water area, the filter feeding purification area occupies 45-50% of the water area and the deep purification area occupies 25-30% of the water area. Vallisneria natans or Hydrilla verticillata are planted at the bottom of the deep purification area, and microporous oxygenation facilities and air-lift water-pushing devices are installed. (2) Pond pretreatment: Before filling the pond, the bottom of the pond is dredged and exposed to the sun. Quicklime is used to disinfect the whole pond. After filling the pond to 0.8-1.0m, tea seed cake is used to kill wild fish. After the drug has worn off, fermented and decomposed chicken manure or pig manure is applied at a rate of 130kg / mu. Then the water is replenished to 1.5-2.0m. (3) Stocking basic filter-feeding fish and shellfish: When the water transparency of the pond reaches 30-40cm, silver carp and bighead carp are stocked in the filter-feeding purification zone. The stocking density of silver carp is 180 fish / mu, and the size is 100-200g / fish. The stocking density of bighead carp is 90 fish / mu, and the size is 200-500g / fish. Triangular sail mussels are stocked in the deep purification zone by suspension. The stocking density is 900 mu, and the suspension depth is 0.5-1.5m underwater. (4) Stocking the main fish species: When the water temperature is stable above 15℃, stock California bass fry in the main breeding area. The stocking density of California bass fry is 2800 fish / acre, and the size is 10-15cm / fish. Before stocking, the fish should be disinfected by soaking in 3% saline solution for 10 minutes. (5) Management and microecological regulation of aquaculture process: Feed high-protein extruded compound feed to California bass in the main aquaculture area. The daily feeding amount is 3% of the body weight of the fish in the pond. Turn on the air lift water push device to maintain the water body in the direction of main aquaculture area → filter feeding purification area → deep purification area → main aquaculture area. Every 8 days, add functional compound microecological preparations to the sewage collection point of the main aquaculture area and the connecting channel between the main aquaculture area and the filter feeding purification area. The amount added is 0.25 kg / mu. (6) Harvesting adult fish in batches: In the middle and late stages of aquaculture, when the size of the California bass in the main aquaculture area reaches the commercial size, the large ones are caught and the small ones are left to grow, and the fish are harvested in batches by rotation. When the filter-feeding fish in the filter-feeding purification area reach the commercial size or the biomass exceeds the environmental carrying capacity, timely harvesting is carried out. At the same time, the growth status of shellfish is monitored regularly, and when they reach the commercial size, they are harvested and restocked.

[0040] In step (5), the preparation method of the functionalized compound microecological preparation is as follows: S1. Add 100g of zeolite powder to 1L of ethanol-water solution (ethanol to water volume ratio of 8.5:1.5), then add 8g of γ-glycidyl etheroxypropyltrimethoxysilane, and react at 65℃ for 5h. After the reaction is complete, filter, wash, and dry to obtain pretreated zeolite powder. Add 100g of pretreated zeolite powder to 1L of deionized water, then add 1.6g of γ-aminobutyric acid, 2.5g of taurine, and 2g of triethylamine, and react at 55℃ for 14h. After the reaction is complete, filter, wash, and dry to obtain modified zeolite powder. S2. Mix 25g of Bacillus laterosporus, 25g of nitrifying bacteria, 15g of denitrifying bacteria and 15g of sulfur-oxidizing bacteria to prepare a compound bacterial solution (total viable count ≥ 6 × 10⁻⁶). 9(cfu / mL), then 100g of modified zeolite powder was added to 1.5L of the compound bacterial solution, and the mixture was shaken and adsorbed at 33℃ for 3h. After adsorption was completed, the mixture was filtered, and 100g of solid product and 15g of trehalose were added to 900g of sodium alginate aqueous solution with a mass concentration of 2%, and stirred to form a suspension. Then the suspension was added dropwise to calcium chloride aqueous solution with a mass concentration of 3%, and allowed to stand for 50min to solidify. After filtration, washing, and vacuum freeze-drying, the functionalized compound microecological preparation was obtained.

[0041] Compared with Example 1, FeS was not introduced into the functionalized compound microecological preparation of this comparative example, i.e., step S1 was omitted.

[0042] Comparative Example 2 A multi-trophic-level ecological aquaculture method for freshwater fish includes the following steps: (1) Planar partitioning and repair of the aquaculture system: The pond water surface is divided into three independent functional areas from the inlet to the outlet using a permeable mesh, namely the main aquaculture area, the filter feeding purification area and the deep purification area. The main aquaculture area occupies 20-25% of the water area, the filter feeding purification area occupies 45-50% of the water area and the deep purification area occupies 25-30% of the water area. Vallisneria natans or Hydrilla verticillata are planted at the bottom of the deep purification area, and microporous oxygenation facilities and air-lift water-pushing devices are installed. (2) Pond pretreatment: Before filling the pond, the bottom of the pond is dredged and exposed to the sun. Quicklime is used to disinfect the whole pond. After filling the pond to 0.8-1.0m, tea seed cake is used to kill wild fish. After the drug has worn off, fermented and decomposed chicken manure or pig manure is applied at a rate of 130kg / mu. Then the water is replenished to 1.5-2.0m. (3) Stocking basic filter-feeding fish and shellfish: When the water transparency of the pond reaches 30-40cm, silver carp and bighead carp are stocked in the filter-feeding purification zone. The stocking density of silver carp is 180 fish / mu, and the size is 100-200g / fish. The stocking density of bighead carp is 90 fish / mu, and the size is 200-500g / fish. Triangular sail mussels are stocked in the deep purification zone by suspension. The stocking density is 900 mu, and the suspension depth is 0.5-1.5m underwater. (4) Stocking the main fish species: When the water temperature is stable above 15℃, stock California bass fry in the main breeding area. The stocking density of California bass fry is 2800 fish / acre, and the size is 10-15cm / fish. Before stocking, the fish should be disinfected by soaking in 3% saline solution for 10 minutes. (5) Management and microecological regulation of aquaculture process: Feed high-protein extruded compound feed to California bass in the main aquaculture area. The daily feeding amount is 3% of the body weight of the fish in the pond. Turn on the air lift water push device to maintain the water body in the direction of main aquaculture area → filter feeding purification area → deep purification area → main aquaculture area. Every 8 days, add functional compound microecological preparations to the sewage collection point of the main aquaculture area and the connecting channel between the main aquaculture area and the filter feeding purification area. The amount added is 0.25 kg / mu. (6) Harvesting adult fish in batches: In the middle and late stages of aquaculture, when the size of the California bass in the main aquaculture area reaches the commercial size, the large ones are caught and the small ones are left to grow, and the fish are harvested in batches by rotation. When the filter-feeding fish in the filter-feeding purification area reach the commercial size or the biomass exceeds the environmental carrying capacity, timely harvesting is carried out. At the same time, the growth status of shellfish is monitored regularly, and when they reach the commercial size, they are harvested and restocked.

[0043] In step (5), the preparation method of the functionalized compound microecological preparation is as follows: S1. Disperse 100g of zeolite powder in 1.5L of 0.4mol / L ferrous sulfate solution and stir for 35min under nitrogen atmosphere. Then, add 2L of 0.4mol / L sodium sulfide solution dropwise under stirring and stir at 25℃ for 1.5h. After the reaction is completed, filter, wash and dry to obtain composite zeolite powder. S2. Add 100g of composite zeolite powder to 1L of ethanol-water solution (ethanol to water volume ratio of 8.5:1.5), then add 8g of γ-glycidyl etheroxypropyltrimethoxysilane, and react at 65℃ for 5h. After the reaction is complete, filter, wash, and dry to obtain pretreated zeolite powder. Add 100g of pretreated zeolite powder to 1L of deionized water, then add 1.6g of γ-aminobutyric acid and 2g of triethylamine, and react at 55℃ for 14h. After the reaction is complete, filter, wash, and dry to obtain modified zeolite powder. S3. Mix 25g of Bacillus laterosporus, 25g of nitrifying bacteria, 15g of denitrifying bacteria and 15g of sulfur-oxidizing bacteria to prepare a compound bacterial solution (total viable count ≥ 6 × 10⁻⁶). 9 (cfu / mL), then 100g of modified zeolite powder was added to 1.5L of the compound bacterial solution, and the mixture was shaken and adsorbed at 33℃ for 3h. After adsorption was completed, the mixture was filtered, and 100g of solid product and 15g of trehalose were added to 900g of sodium alginate aqueous solution with a mass concentration of 2%, and stirred to form a suspension. Then the suspension was added dropwise to calcium chloride aqueous solution with a mass concentration of 3%, and allowed to stand for 50min to solidify. After filtration, washing, and vacuum freeze-drying, the functionalized compound microecological preparation was obtained.

[0044] Compared with Example 1, taurine was not introduced into the functionalized compound microecological preparation in this comparative example.

[0045] Comparative Example 3 A multi-trophic-level ecological aquaculture method for freshwater fish includes the following steps: (1) Planar partitioning and repair of the aquaculture system: The pond water surface is divided into three independent functional areas from the inlet to the outlet using a permeable mesh, namely the main aquaculture area, the filter feeding purification area and the deep purification area. The main aquaculture area occupies 20-25% of the water area, the filter feeding purification area occupies 45-50% of the water area and the deep purification area occupies 25-30% of the water area. Vallisneria natans or Hydrilla verticillata are planted at the bottom of the deep purification area, and microporous oxygenation facilities and air-lift water-pushing devices are installed. (2) Pond pretreatment: Before filling the pond, the bottom of the pond is dredged and exposed to the sun. Quicklime is used to disinfect the whole pond. After filling the pond to 0.8-1.0m, tea seed cake is used to kill wild fish. After the drug has worn off, fermented and decomposed chicken manure or pig manure is applied at a rate of 130kg / mu. Then the water is replenished to 1.5-2.0m. (3) Stocking basic filter-feeding fish and shellfish: When the water transparency of the pond reaches 30-40cm, silver carp and bighead carp are stocked in the filter-feeding purification zone. The stocking density of silver carp is 180 fish / mu, and the size is 100-200g / fish. The stocking density of bighead carp is 90 fish / mu, and the size is 200-500g / fish. Triangular sail mussels are stocked in the deep purification zone by suspension. The stocking density is 900 mu, and the suspension depth is 0.5-1.5m underwater. (4) Stocking the main fish species: When the water temperature is stable above 15℃, stock California bass fry in the main breeding area. The stocking density of California bass fry is 2800 fish / acre, and the size is 10-15cm / fish. Before stocking, the fish should be disinfected by soaking in 3% saline solution for 10 minutes. (5) Management and microecological regulation of aquaculture process: Feed high-protein extruded compound feed to California bass in the main aquaculture area. The daily feeding amount is 3% of the body weight of the fish in the pond. Turn on the air lift water push device to maintain the water body in the direction of main aquaculture area → filter feeding purification area → deep purification area → main aquaculture area. Every 8 days, add functional compound microecological preparations to the sewage collection point of the main aquaculture area and the connecting channel between the main aquaculture area and the filter feeding purification area. The amount added is 0.25 kg / mu. (6) Harvesting adult fish in batches: In the middle and late stages of aquaculture, when the size of the California bass in the main aquaculture area reaches the commercial size, the large ones are caught and the small ones are left to grow, and the fish are harvested in batches by rotation. When the filter-feeding fish in the filter-feeding purification area reach the commercial size or the biomass exceeds the environmental carrying capacity, timely harvesting is carried out. At the same time, the growth status of shellfish is monitored regularly, and when they reach the commercial size, they are harvested and restocked.

[0046] In step (5), the preparation method of the functionalized compound microecological preparation is as follows: S1. Disperse 100g of zeolite powder in 1.5L of 0.4mol / L ferrous sulfate solution and stir for 35min under nitrogen atmosphere. Then, add 2L of 0.4mol / L sodium sulfide solution dropwise under stirring and stir at 25℃ for 1.5h. After the reaction is completed, filter, wash and dry to obtain composite zeolite powder. S2. Add 100g of composite zeolite powder to 1L of ethanol-water solution (ethanol to water volume ratio of 8.5:1.5), then add 8g of γ-glycidyl etheroxypropyltrimethoxysilane, and react at 65℃ for 5h. After the reaction is complete, filter, wash, and dry to obtain pretreated zeolite powder. Add 100g of pretreated zeolite powder to 1L of deionized water, then add 2.5g of taurine and 2g of triethylamine, and react at 55℃ for 14h. After the reaction is complete, filter, wash, and dry to obtain modified zeolite powder. S3. Mix 25g of Bacillus laterosporus, 25g of nitrifying bacteria, 15g of denitrifying bacteria and 15g of sulfur-oxidizing bacteria to prepare a compound bacterial solution (total viable count ≥ 6 × 10⁻⁶). 9 (cfu / mL), then 100g of modified zeolite powder was added to 1.5L of the compound bacterial solution, and the mixture was shaken and adsorbed at 33℃ for 3h. After adsorption was completed, the mixture was filtered, and 100g of solid product and 15g of trehalose were added to 900g of sodium alginate aqueous solution with a mass concentration of 2%, and stirred to form a suspension. Then the suspension was added dropwise to calcium chloride aqueous solution with a mass concentration of 3%, and allowed to stand for 50min to solidify. After filtration, washing, and vacuum freeze-drying, the functionalized compound microecological preparation was obtained.

[0047] Compared with Example 1, the functionalized compound microecological preparation in this comparative example did not introduce γ-aminobutyric acid.

[0048] Comparative Example 4 A multi-trophic-level ecological aquaculture method for freshwater fish includes the following steps: (1) Planar partitioning and repair of the aquaculture system: The pond water surface is divided into three independent functional areas from the inlet to the outlet using a permeable mesh, namely the main aquaculture area, the filter feeding purification area and the deep purification area. The main aquaculture area occupies 20-25% of the water area, the filter feeding purification area occupies 45-50% of the water area and the deep purification area occupies 25-30% of the water area. Vallisneria natans or Hydrilla verticillata are planted at the bottom of the deep purification area, and microporous oxygenation facilities and air-lift water-pushing devices are installed. (2) Pond pretreatment: Before filling the pond, the bottom of the pond is dredged and exposed to the sun. Quicklime is used to disinfect the whole pond. After filling the pond to 0.8-1.0m, tea seed cake is used to kill wild fish. After the drug has worn off, fermented and decomposed chicken manure or pig manure is applied at a rate of 130kg / mu. Then the water is replenished to 1.5-2.0m. (3) Stocking basic filter-feeding fish and shellfish: When the water transparency of the pond reaches 30-40cm, silver carp and bighead carp are stocked in the filter-feeding purification zone. The stocking density of silver carp is 180 fish / mu, and the size is 100-200g / fish. The stocking density of bighead carp is 90 fish / mu, and the size is 200-500g / fish. Triangular sail mussels are stocked in the deep purification zone by suspension. The stocking density is 900 mu, and the suspension depth is 0.5-1.5m underwater. (4) Stocking the main fish species: When the water temperature is stable above 15℃, stock California bass fry in the main breeding area. The stocking density of California bass fry is 2800 fish / acre, and the size is 10-15cm / fish. Before stocking, the fish should be disinfected by soaking in 3% saline solution for 10 minutes. (5) Management and microecological regulation of aquaculture process: Feed high-protein extruded compound feed to California bass in the main aquaculture area. The daily feeding amount is 3% of the body weight of the fish in the pond. Turn on the air lift water push device to maintain the water body in the direction of main aquaculture area → filter feeding purification area → deep purification area → main aquaculture area. Every 8 days, add functional compound microecological preparations to the sewage collection point of the main aquaculture area and the connecting channel between the main aquaculture area and the filter feeding purification area. The amount added is 0.25 kg / mu. (6) Harvesting adult fish in batches: In the middle and late stages of aquaculture, when the size of the California bass in the main aquaculture area reaches the commercial size, the large ones are caught and the small ones are left to grow, and the fish are harvested in batches by rotation. When the filter-feeding fish in the filter-feeding purification area reach the commercial size or the biomass exceeds the environmental carrying capacity, timely harvesting is carried out. At the same time, the growth status of shellfish is monitored regularly, and when they reach the commercial size, they are harvested and restocked.

[0049] In step (5), the preparation method of the functionalized compound microecological preparation is as follows: S1. Mix 100g of zeolite powder with 30g of FeS powder evenly to obtain composite zeolite powder; S2. Mix 100g of composite zeolite powder with 1.6g of γ-aminobutyric acid and 2.5g of taurine to obtain modified zeolite powder. S3. Mix 25g of Bacillus laterosporus, 25g of nitrifying bacteria, 15g of denitrifying bacteria and 15g of sulfur-oxidizing bacteria to prepare a compound bacterial solution (total viable count ≥ 6 × 10⁻⁶). 9 (cfu / mL), then 100g of modified zeolite powder was added to 1.5L of the compound bacterial solution, and the mixture was shaken and adsorbed at 33℃ for 3h. After adsorption was completed, the mixture was filtered, and 100g of solid product and 15g of trehalose were added to 900g of sodium alginate aqueous solution with a mass concentration of 2%, and stirred to form a suspension. Then the suspension was added dropwise to calcium chloride aqueous solution with a mass concentration of 3%, and allowed to stand for 50min to solidify. After filtration, washing, and vacuum freeze-drying, the functionalized compound microecological preparation was obtained.

[0050] Compared with Example 1, the modified zeolite powder in this comparative example was prepared by simple physical mixing of zeolite powder, FeS, γ-aminobutyric acid, and taurine.

[0051] The functionalized composite microecological preparations obtained in Example 1, Comparative Examples 1 and 4 were tested for sulfide removal rate. A blank control group without any preparation was also included. Specifically, several 1000mL beakers were taken, and 1000mL of sulfide solution (prepared with sodium sulfide) with an initial concentration (C0) of 5.0mg / L was added to each beaker. Then, 1.0g of the corresponding preparation sample (i.e., a dosage of 1g / L) was added to each experimental group beaker. No preparation was added to the blank control group. All beakers were placed on a constant temperature (25℃) magnetic stirrer and continuously stirred slowly to simulate an aquatic environment. Samples were taken from each beaker at 1 hour, 3 hours, 6 hours, and 24 hours after addition. The residual concentration of sulfide in the water samples (C0) was determined using the national standard method "Determination of Sulfides in Water - Methylene Blue Spectrophotometric Method" (GB / T 16489-1996). t Each treatment was performed in triplicate, and the results were averaged. The sulfide removal rate was calculated as follows: Removal rate (%) = (C0 - C) / ... t ) / C0×100%, where C0 is the initial concentration, C t The residual concentration is shown in Table 1 below.

[0052] Table 1. Results of sulfide removal rate tests for each group As can be seen from Table 1 above, the functionalized composite microecological preparation prepared by the present invention has excellent sulfide removal effect.

[0053] After a complete culture cycle (180 days) of Examples 1-3 and Comparative Examples 1-4, the growth indicators of California bass in each pond were statistically analyzed, and the results are shown in Table 2 below.

[0054] Table 2. Growth performance results of each group of California bass As can be seen from Table 2 above, the multi-trophic-level ecological aquaculture method for freshwater fish of the present invention has significant advantages in increasing production, reducing disease, and improving feed utilization, and can effectively improve the growth performance of freshwater fish.

[0055] In Example 1, during the aquaculture process of Comparative Examples 1-4, pond water samples were collected at different time periods to measure ammonia nitrogen and COD. The ammonia nitrogen content in the water was determined according to HJ 535-2009 "Determination of Ammonia Nitrogen in Water Quality - Nessler's Reagent Spectrophotometric Method"; the COD value of the water was measured using a COD analyzer; the results are as follows. Figs. 1-2 .

[0056] from Fig. 1 and Fig. 2 As can be seen, the multi-trophic-level ecological aquaculture method for freshwater fish provided by this invention can effectively reduce the concentration of ammonia nitrogen and COD in the water, and can establish a stable, efficient and sustainable benign aquatic micro-ecosystem.

[0057] The above description is a further detailed explanation of the present invention in conjunction with specific implementation examples. It should not be considered that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered to fall within the protection scope of the present invention.

[0058] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-trophic-level ecological aquaculture method for freshwater fish, characterized in that, Includes the following steps: (1) The pond water surface is divided into three independent functional areas from the inlet to the outlet using a permeable mesh, namely the main breeding area, the filter feeding purification area and the deep purification area. Submerged plants are planted at the bottom of the deep purification area, and microporous oxygenation facilities and air-lift water-pushing devices are installed. (2) Before filling the pond, the bottom of the pond should be dredged and exposed to the sun. Quicklime should be sprinkled throughout the pond for disinfection. After filling the pond to 0.8-1.0m, tea seed cake should be used to kill wild fish. After the effects of the medicine have disappeared, fermented organic fertilizer should be applied, and then the water should be replenished to 1.5-2.0m. (3) When the water transparency of the pond reaches 30-40cm, silver carp and bighead carp are released into the filter feeding purification zone, and triangular sail mussels or pleated crown mussels are released into the deep purification zone by hanging. (4) When the water temperature is stable above 15℃, stock California bass fry in the main culture area; (5) Feed high-protein extruded compound feed to California bass in the main culture area. The daily feeding amount is 2%-4% of the body weight of the fish in the pond. Turn on the air lift water push device to maintain the water body circulating in the direction of main culture area → filter feeding purification area → deep purification area → main culture area. Every 7-10 days, add functional compound microecological preparations to the sewage collection point of the main culture area and the connecting channel between the main culture area and the filter feeding purification area. The amount added is 0.2-0.3 kg / mu. (6) Harvest the finished fish in batches.

2. The multi-trophic-level ecological aquaculture method for freshwater fish according to claim 1, characterized in that, In step (1), the main aquaculture area occupies 20-25% of the water area, the filter feeding and purification area occupies 45-50% of the water area, and the deep purification area occupies 25-30% of the water area; the submerged plants are Vallisneria natans or Hydrilla verticillata.

3. The multi-trophic-level ecological aquaculture method for freshwater fish according to claim 1, characterized in that, In step (2), the fermented organic fertilizer is fermented and decomposed chicken manure or pig manure, and the application rate is 100-150 kg / mu.

4. The multi-trophic-level ecological aquaculture method for freshwater fish according to claim 1, characterized in that, In step (3), the stocking density of silver carp is 150-200 fish / mu, and the size is 100-200g / fish; the stocking density of bighead carp is 80-100 fish / mu, and the size is 200-500g / fish; the stocking density of triangular sail mussel or pleated crown mussel is 800-1000 mu, and the hanging depth is 0.5-1.5m underwater.

5. The multi-trophic-level ecological aquaculture method for freshwater fish according to claim 1, characterized in that, In step (4), the stocking density of the California bass fry is 2,500-3,000 fish / acre, and the size is 10-15cm / fish; before stocking, the fish need to be disinfected by soaking in 3%-4% saline solution for 5-10 minutes.

6. The multi-trophic-level ecological aquaculture method for freshwater fish according to claim 1, characterized in that, In step (5), the preparation method of the functionalized compound microecological preparation is as follows: S1. Disperse zeolite powder in ferrous sulfate solution and stir for 30-40 minutes under nitrogen atmosphere. Then, add sodium sulfide solution dropwise under stirring conditions and carry out the stirring reaction. After the reaction is completed, filter, wash and dry to obtain composite zeolite powder. S2. Add the composite zeolite powder to an ethanol aqueous solution, then add γ-glycidyl etheroxypropyltrimethoxysilane and carry out a constant temperature reaction. After the reaction is completed, filter, wash, and dry to obtain pretreated zeolite powder. Add the pretreated zeolite powder to deionized water, then add γ-aminobutyric acid, taurine, and triethylamine and carry out a heating reaction. After the reaction is completed, filter, wash, and dry to obtain modified zeolite powder. S3. Mix Bacillus laterosporus, nitrifying bacteria, denitrifying bacteria and sulfur-oxidizing bacteria to prepare a compound bacterial solution. Then add modified zeolite powder to the compound bacterial solution and shake to adsorb. After adsorption is completed, filter. Add the solid product and trehalose to sodium alginate aqueous solution and stir to form a suspension. The suspension was then added dropwise to an aqueous calcium chloride solution, allowed to stand and solidify, filtered, washed, and freeze-dried under vacuum to obtain the functionalized composite microecological preparation.

7. The multi-trophic-level ecological aquaculture method for freshwater fish according to claim 6, characterized in that, In step S1, the concentration of the ferrous sulfate solution is 0.3-0.5 mol / L, the concentration of the sodium sulfide solution is 0.3-0.5 mol / L, the mass-volume ratio of the zeolite powder, ferrous sulfate solution, and sodium sulfide solution is 1 g: 10-20 mL: 15-25 mL, and the stirring reaction temperature is 20-30℃ for 1-2 hours.

8. The multi-trophic-level ecological aquaculture method for freshwater fish according to claim 6, characterized in that, In step S2, the volume ratio of ethanol to water in the ethanol-water solution is 8-9:1-2, the mass ratio of the composite zeolite powder to γ-glycidoxypropyltrimethoxysilane is 100:6-10, the isothermal reaction temperature is 60-70℃, and the time is 4-6h; the mass ratio of the pretreated zeolite powder, γ-aminobutyric acid, taurine, and triethylamine is 100:1.2-2:1.8-3:1.5-2.5, the heating reaction temperature is 50-60℃, and the time is 12-16h.

9. The multi-trophic-level ecological aquaculture method for freshwater fish according to claim 6, characterized in that, In step S3, the ratio of Bacillus laterosporus, nitrifying bacteria, denitrifying bacteria, and sulfur-oxidizing bacteria in the compound bacterial solution is 2-3:2-3:1-2:1-2, and the total viable count is ≥6×10⁻⁶. 9 The mass-to-volume ratio of the modified zeolite powder to the composite bacterial solution is 1 g: 10-20 mL; the temperature for the shaking adsorption is 30-35℃, and the time is 2-4 h; the mass concentration of the sodium alginate aqueous solution is 1.5-2.5%; the mass ratio of the solid product, trehalose, and sodium alginate aqueous solution is 10:1-2:80-100; the mass concentration of the calcium chloride aqueous solution is 2-4%; and the time for static solidification is 30-60 min.

10. The multi-trophic-level ecological aquaculture method for freshwater fish according to claim 1, characterized in that, In step (6), the specific method for harvesting finished fish in batches is as follows: in the middle and late stages of aquaculture, when the individual size of California bass in the main aquaculture area reaches the commercial size, the method of catching the big ones and leaving the small ones, and rotating the harvesting and releasing is adopted for batch harvesting; when the filter-feeding fish in the filter-feeding purification area reach the commercial size or the biomass exceeds the environmental carrying capacity, timely harvesting is carried out; at the same time, the growth status of shellfish is monitored regularly, and when they reach the commercial size, they are harvested and restocked.

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