Method for increasing survival rate of zoeae of macrobrachium nipponensis based on bacterium-membrane synergy
By using porous biofilm technology and feeding different feeds in stages, the problems of unstable water quality, frequent diseases and high larval mortality in Japanese prawn breeding have been solved, the larval survival rate has been improved and the use of antibiotics has been reduced, and it is suitable for a variety of aquaculture scenarios.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-19
- Publication Date
- 2026-04-14
AI Technical Summary
Traditional Japanese prawn breeding suffers from problems such as poor water quality stability, frequent disease outbreaks, low feed conversion rate, and high larval mortality, especially during specific developmental stages where larval survival rates are low.
The porous biofilm technology utilizes porous carriers loaded with microorganisms, such as porous carbon fiber carriers or porous polyethylene biocarriers, to form a bacterial community dominated by Proteobacteria. Combined with water quality management and phased feeding of different feeds, including shrimp chips, spirulina powder, vitamin C, and povidone-iodine disinfected cladoceran feed, the bacterial community dominated by Proteobacteria is formed. Through nitrification-denitrification and polyphosphate accumulation, the eutrophication of the water body is reduced, natural food and shelter are provided, and water flow disturbance is reduced.
It significantly improves water quality, enhances the resilience of larvae, increases seedling survival rate to 60-80%, reduces pathogen infection rate, reduces antibiotic use, saves costs, and is suitable for ponds, cages, and indoor recirculating water systems.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of seedling technology, and in particular to a method for improving the survival rate of zoea larvae of the Japanese giant freshwater prawn based on the synergistic effect of bacteria and biofilm. Background Technology
[0002] The Japanese giant freshwater prawn (Macrobrachium nipponense) is a freshwater shrimp widely distributed throughout East Asia, found in rivers, lakes, and ponds in China, Japan, and the Korean Peninsula. Its meat is delicious and nutritious, making it an important economic freshwater shrimp species. Due to overfishing, water pollution, and ecological damage, the natural population of Japanese giant freshwater prawns has gradually decreased, leading to an increase in the scale of artificial breeding.
[0003] Traditional Japanese giant freshwater prawn (Macrobrachium nipponense) breeding has the following problems: 1. Poor water quality stability: The accumulation of ammonia nitrogen and nitrite leads to larval poisoning, and insufficient dissolved oxygen causes surfacing and death. 2. Frequent disease outbreaks: High infection rate of pathogens during molting, and antibiotic overuse leading to drug resistance. 3. Low feed conversion rate: Poor palatability of artificial feed, insufficient feeding efficiency of larvae, and even food decomposition causing water quality deterioration. 4. In existing technologies, two methods are generally used: artificial breeding ponds or direct release of net cages into the water. For example, the direct release of berried shrimp into net cages (DB3201 / T 1195-2024) can optimize density, but it relies on frequent water changes (30% daily) for water quality control, which is costly and lacks ecological stability. 5. During special developmental stages of the Japanese giant freshwater prawn, due to changes in habits, the mortality rate of larvae is high. Summary of the Invention
[0004] In view of this, the purpose of this invention is to provide a method for improving the survival rate of zoea larvae of giant freshwater prawns based on the synergistic effect of bacteria and biofilm. When raising giant freshwater prawns, according to the changes in the habits of zoea larvae, by adopting porous biological biofilm and changing the feed, water quality can be significantly improved, the larvae's resistance to stress can be enhanced, and the survival rate of the larvae can be increased.
[0005] The present invention solves the above-mentioned technical problems through the following technical means: A method for improving the survival rate of zoea larvae of the Japanese giant freshwater prawn based on bacterial-membrane synergy includes the following steps: S1. Place the porous carrier in water and perform biofilm formation for 10-16 days to obtain a porous carrier loaded with microorganisms. S2. Place the porous carrier loaded with microorganisms into the seedling device, then release the Japanese giant freshwater shrimp larvae into the seedling device, and manage the water quality and temperature. S3. Feed Japanese prawn larvae different feeds at different growth stages and add supplementary feeds.
[0006] Based on the above-mentioned technical means, by using porous carriers loaded with microorganisms and changing the feed during the breeding of Japanese prawn larvae, it is possible to significantly improve water quality, enhance the stress resistance of larvae, and increase the survival rate of larvae in indoor breeding ponds.
[0007] Preferably, in step S1, the porous carrier is one or more combinations of porous carbon fiber carrier, porous polyethylene biological carrier, bioceramic, sponge, coral stone, volcanic rock, biological rope, biological ball, porous brick, porous tile, porous polyester fiber material, and porous nylon fiber material.
[0008] Further preferred, the porous carrier is a porous carbon fiber carrier or a porous polyethylene biological carrier.
[0009] In a further preferred embodiment, the porous carrier is fixed into a shaped object by a rigid material before use.
[0010] Based on the above-mentioned technical means, the periphery of the porous carrier material can be fixed by aluminum alloy, hard plastic, stainless steel, etc., to form rectangles, squares, etc., thus facilitating its use.
[0011] Further preferred, the porous carrier has a density of 40-80 mesh.
[0012] Further preferred, the porous carrier has a density of 60 mesh.
[0013] Preferably, in step S1, when performing the biofilm formation operation, the porous carrier is placed in a natural water body, and the biofilm is formed for 14-16 days at a water temperature of 25-30℃.
[0014] More preferably, when the porous carrier is attached to a membrane for 14-16 days, a Proteobacteria flora forms on the porous carrier, and the number of Proteobacteria flora is ≥60%.
[0015] Further preferred, the bacterial community containing Proteobacteria includes polyphosphate-accumulating bacteria, nitrifying bacteria, and denitrifying bacteria, and the number of individual bacteria in the Proteobacteria community accounts for ≥70% of the total number of individuals in the entire bacterial community.
[0016] Based on the above-mentioned technical means, by forming a bacterial community dominated by Proteobacteria, the Proteobacteria community reduces eutrophication of water bodies through nitrogen fixation and phosphorus removal (nitrification-denitrification, phosphorus uptake by polyphosphate-accumulating bacteria), thereby significantly improving the water quality control capacity and reducing the fluctuation range of ammonia nitrogen, thus reducing the impact on the growth of Japanese giant freshwater shrimp larvae.
[0017] Preferably, in step S1, when performing the biofilm formation operation, the porous carrier is placed in the composite bacterial solution and the biofilm is formed for 9-11 days at a water temperature of 25-28℃.
[0018] More preferably, the compound bacterial solution contains at least two of the following: nitrifying bacteria, Bacillus, lactic acid bacteria, denitrifying bacteria, photosynthetic bacteria, Vibrio antagonistic bacteria, and EM bacteria.
[0019] More preferably, the compound bacterial solution comprises nitrifying bacteria, Bacillus, and lactic acid bacteria, and the initial inoculation dose of the compound bacterial solution is 0.5-1 g / m³. 3 .
[0020] Further preferred, nitrifying bacteria, Bacillus, and lactic acid bacteria are mixed in a 1:1:1 ratio, and the total activity unit of the compound bacterial solution is 1*102 8 CFU / mL.
[0021] Further preferably, during the biofilm formation process of the composite bacterial solution, microporous aeration is performed, with the aeration rate controlled at 0.13 / (h·m). 3 ).
[0022] Based on the aforementioned technical methods, the combined use of nitrifying bacteria, Bacillus, and lactic acid bacteria can, on the one hand, reduce the ammonia nitrogen content in the water, thereby reducing toxic damage to the gills and epidermis of juveniles. It can also decompose uneaten feed, feces, and other organic matter, reducing the chemical oxygen demand (COD) and preventing water quality deterioration. On the other hand, it can promote the uniform distribution of dissolved oxygen in the water, avoiding localized hypoxia (such as dead corners at the bottom of the pond). Through the synergistic effect of microporous aeration and biofilm, dissolved oxygen can be stabilized at ≥5 mg / L, meeting the high oxygen consumption requirements of juveniles. Furthermore, beneficial bacteria occupy ecological niches and secrete antibacterial substances (such as bacteriocins), inhibiting the reproduction of pathogens such as Vibrio and Aeromonas, reducing the incidence of diseases such as bacterial gill rot in juveniles. Through biological control, some antibiotics can be replaced, reducing the side effects of drug residues on juveniles (such as hepatopancreatic damage).
[0023] After the porous carrier is attached to the membrane, the algae and protozoa (such as ciliates) attached to the surface can serve as natural food for the larvae, especially supplementing the nutrition of the larvae in stages I-III, enhancing the synchronicity of molting, and some microorganisms secrete digestive enzymes (proteases, lipases) and B vitamins, which promotes the absorption and utilization rate of artificial food by the larvae.
[0024] Preferably, in step S2, when managing water quality and controlling temperature, 20-25% of the water is changed daily, and the water temperature is kept constant at 28±1℃.
[0025] A further preferred method is to filter the water through expanded polystyrene foam during daily water changes.
[0026] In a further preferred embodiment, during water quality management and temperature control in step S2, an air-filled stone is added to adjust the air volume to a microbubble state, resulting in a dissolved oxygen content ≥5 mg / L.
[0027] A further preferred option is an aerated stone with a mesh size of 40.
[0028] Based on the above-mentioned technical means, by using aeration stones for aeration, the collision damage to Japanese giant prawn larvae caused by water flow disturbance can be reduced, and by dissolving oxygen through aeration, oxygen can be provided for microorganisms in the water and Japanese giant prawn larvae.
[0029] Further preferred, when conducting water quality management and temperature control, the light intensity is ≤500 lux.
[0030] Based on the above-mentioned technical means, the light intensity can be controlled by using devices such as shading nets to reduce phototaxis stress in Japanese prawn larvae.
[0031] Preferably, in step S3, the different growth stages of the Japanese giant freshwater prawn larvae include stages II-IV, V-VII, and VIII-larval stage, and different feeds and supplements are provided during stages I-IV, V-VII, and VIII-larval stage respectively.
[0032] Further preferred method is to feed shrimp chips and spirulina powder during stages II-IV at a rate of 0.1-0.15g / 10,000 shrimp, once every 2-4 hours.
[0033] More preferably, the particle size of the shrimp chips and spirulina powder is ≤150μm, and the mass ratio of shrimp chips to spirulina powder is 10:1.
[0034] Further preferred, during stages V-VII, artificial pelleted feed supplemented with vitamin C is provided.
[0035] Further preferred, the particle size of the bait is ≤250μm.
[0036] Further preferred, the amount of vitamin C added to the artificial pellet feed is 2-3 g / kg.
[0037] According to the above-mentioned technical means, adding vitamin C to the water can enhance the immunity of Japanese prawn larvae and also have a disinfection effect, reducing the risk of pathogens.
[0038] Further preferred method is to feed cladoceran feed sterilized with povidone-iodine during the VIII-larval stage.
[0039] Further preferred, the feeding amount of povidone-iodine disinfected cladoceran feed is 0.8-1.2g / 10,000 cladocerans.
[0040] Further preferred, povidone-iodine disinfected cladoceran feed should be soaked for 10-20 minutes before use.
[0041] Further preferred, the amount of povidone-iodine disinfected cladoceran feed added during soaking is 0.25-0.5 g / kg.
[0042] Based on the above-mentioned technical means, the use of povidone-iodine disinfection for cladoceran feed can kill pathogen carriers, prevent shrimp larvae from being infected, indirectly optimize the breeding environment, reduce harmful competition for shrimp larvae, and reduce the accumulation of toxins produced by the decomposition of dead cladocerans after povidone-iodine disinfection, thereby reducing the harm of toxins to shrimp larvae.
[0043] Further preferred, during stages IV-V, the aeration intensity is reduced, and a porous carrier loaded with microorganisms is used as a substrate for the microorganisms to cover the microorganisms, with dissolved oxygen ≥4mg / L.
[0044] Based on the above technical means, by reducing the inflation intensity, the disturbance of gas and water flow to shrimp larvae is reduced, and a porous carrier loaded with microorganisms provides attachment for the larvae, thereby reducing the mortality rate of shrimp larvae.
[0045] Further preferred, during the IX-larval stage, the peak ammonia nitrogen level is monitored (controlled to ≤0.60 mg / L), and natural feed is provided by microorganisms on the surface of the porous carrier.
[0046] The present application, employing the above technical solution, has at least the following beneficial effects: 1. Since zoea larvae of the Japanese giant prawn prefer to live in calm waters with gentle currents, using porous carriers for attachment provides them with some shelter, reducing the stimulation of water flow and thus improving their survival rate in stages IV-V. A similar effect occurs in stages IX to the larval stage. While larval larvae are fully developed and their habits are similar to adults, stage IX zoea larvae are still developing and their habits differ significantly from adults, particularly in their swimming style, changing from the upside-down posture of the zoea stage to horizontal swimming and crawling. Therefore, porous carriers provide a food source and attachment sites, increasing the survival rate to 60-80% compared to the 30-50% survival rate achieved with traditional methods. 2. In this application, by forming a bacterial community dominated by Proteobacteria on a porous carrier, the Proteobacteria reduce eutrophication of the water body through nitrogen fixation and phosphorus removal (nitrification-denitrification, phosphorus uptake by polyphosphate-accumulating bacteria), thereby significantly improving the water quality control capacity and reducing the fluctuation range of ammonia nitrogen, reducing the impact on the growth of Japanese giant prawn larvae and improving the survival rate of Japanese giant prawn larvae. 3. In this application, by using staged screening and feeding of feed matched to the larvae's feeding capacity, feed waste is reduced and feed utilization is improved. Simultaneously, the porous carrier loaded with microorganisms can provide natural feed for the larvae, reducing reliance on artificial feeding and saving costs. 4. In this application, the daily water exchange rate is reduced from the traditional 30% to 20%, resulting in reduced daily water consumption. Furthermore, the water temperature is controlled at 28±1℃, and microbubble aeration further reduces equipment operating energy consumption. 5. In this application, by using a porous carrier loaded with microorganisms, nitrifying bacteria, Bacillus, lactic acid bacteria, and vitamin C, along with povidone-iodine disinfection for cladocerans, the pathogen inhibition rate can reach 40%-60%, and antibiotic usage can be reduced by 70%. 6. The method in this application is applicable to ponds, cages and indoor recirculating water systems, and is suitable for a variety of aquaculture scenarios. Detailed Implementation
[0047] The technical solutions 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. In this application, the porous carrier is a porous carbon fiber carrier or a porous polyethylene biological carrier with a density of 60 mesh. Before use, the periphery of the porous carrier material is fixed with aluminum alloy, rigid plastic, stainless steel, etc., to form a frame, which, together with the porous carrier, forms an artificial matrix. The frame is 1m long and 1m wide, 3cm thick, and 2cm wide.
[0048] Example 1: A method for improving the survival rate of zoea larvae of the Japanese giant freshwater prawn based on bacterial-film synergy. In this embodiment, the experimental site was the seedling workshop of an aquaculture company in North China.
[0049] S1. Place the artificial substrate in the natural water body of the lake, where the water quality meets the Class III surface water standard, and carry out the biofilm formation operation. Under the condition of water temperature of 25-28℃, the biofilm will be formed for 15 days, so that a bacterial community dominated by Proteobacteria will form on the artificial substrate, with the proportion of Proteobacteria ≥60%. S2. The artificial substrate, after being coated with natural water, was placed in seven 5m*5m*1.5m seedling ponds. These ponds were located within a seedling workshop, a brick-concrete structure with a fiberglass roof for better lighting. The workshop was equipped with a complete water inlet / outlet, air supply, and lighting system. The artificial substrate was spaced 30cm apart in each pond, serving as the experimental group. Three other identical ponds were used as the control group without artificial substrate. The same number of Japanese giant freshwater shrimp larvae were then introduced into each pond, and water quality and temperature were controlled. In terms of water quality management and temperature control, each seedling pond undergoes daily water exchange via expanded rubber cotton filtration at 20% capacity, maintaining a constant water temperature of 28±1℃ and a pH of 7.8. Aeration stones with a mesh size of 40 are then added, and the air volume is adjusted to a microbubble state to ensure dissolved oxygen levels in the seedling pond are ≥5mg / L. Light intensity is then controlled to ≤500 lux using shading nets and other methods.
[0050] S3. Feed Japanese freshwater prawn larvae different feeds at different growth stages and add supplementary feeds; Specifically, the growth stages of Japanese prawn larvae include stages I-IV, V-VII, and VIII-larval stage, and stages II-IV, V-VII, and VIII-larval stage.
[0051] During stages II-IV, shrimp chips and spirulina powder filtered through a 100-mesh sieve were fed. The particle size of the shrimp chips and spirulina powder was ≤150μm, the mass ratio of shrimp chips to spirulina powder was 10:1, and the feeding amount was 0.1-0.15g / 10,000 shrimps, fed once every 3 hours. During stages V-VII, artificial pelleted feed with added vitamin C was fed through a 100-mesh sieve. The pellet size of the feed was ≤250μm, and the amount of vitamin C added to the feed was 2g / kg.
[0052] During stages IV-V, the aeration intensity was reduced and artificial substrates were used for shading to reduce the mortality rate of shrimp larvae due to collisions.
[0053] During the VIII-larval stage, feed cladoceran feed sterilized with povidone-iodine at a rate of 0.8-1.2 g / 10,000 cladocerans. Before use, the povidone-iodine sterilized cladoceran feed should be soaked in clean water for 10 minutes at a rate of 0.25 g / kg.
[0054] During the IX-larval stage, the peak ammonia nitrogen level was monitored (controlled to ≤0.60 mg / L), and microorganisms on the surface of porous carriers were used to provide natural food.
[0055] In this embodiment, the survival rates of zoea larvae in stages IV-V and IX of the Japanese giant freshwater prawn are compared in Table 1: Based on the above data, when using natural water bodies in a certain region of North China for natural biofilm formation, comparing the survival rates of *Macrobrachium nipponense* larvae in stage IV with and without artificial substrate, the survival rate increased by about 10% in stage V, and by about 16% in stage IX. This indicates that adding artificial substrate, combined with reduced aeration intensity, can reduce the mortality rate of *Macrobrachium nipponense* larvae due to collisions in stages IV and V. In stage IX, as the larvae transition from an inverted, zoea-like stage to horizontal swimming and crawling, artificial substrate can provide a certain natural food source and a larger area for attachment, thereby improving the survival rate of *Macrobrachium nipponense* larvae.
[0056] Example 2: A Method Two for Improving the Survival Rate of Zoaniopsis larvae of the Japanese giant freshwater prawn based on Bacterial-Membrane Synergy In this embodiment, the experimental site is an aquaculture workshop in a coastal area.
[0057] S1. Place the artificial substrate in a composite bacterial solution. The composite bacterial solution consists of nitrifying bacteria, Bacillus, and lactic acid bacteria, mixed in a 1:1:1 ratio. The total activity unit of the composite bacterial solution is 1*102. 8 CFU / mL. The initial inoculum dose of the compound bacterial suspension is 0.5-1 g / mL. 3 Biofilm formation was carried out at a water temperature of 25-28℃ for 10 days. During biofilm formation, microporous aeration was performed, with the aeration rate controlled at 0.13 g / (h·m³). 3 This allows beneficial bacteria to form on the artificial substrate, and also enables algae, protozoa, and other organisms to attach to it. S2. The artificial substrate coated with compound bacterial solution was placed in three 5m*5m*1.5m seedling ponds. The seedling ponds were located in a seedling workshop, which was a brick-concrete structure with a fiberglass roof for better lighting. The workshop was equipped with a complete water inlet and drainage system, air supply system, and lighting facilities. The artificial substrate was spaced 30cm apart in each seedling pond as the experimental group; the other three identical seedling ponds did not contain artificial substrate as the control group. The same number of Japanese giant freshwater shrimp larvae were then released into each seedling pond, and water quality management and temperature control were implemented. In terms of water quality management and temperature control, each seedling pond undergoes daily water exchange via expanded rubber cotton filtration at 20% capacity, maintaining a constant water temperature of 28±1℃ and a pH of 8.23. Aeration stones with a mesh size of 40 are then added, and the air volume is adjusted to a microbubble state to ensure dissolved oxygen levels in the seedling pond are ≥5mg / L. Light intensity is then controlled to ≤500 lux using shading nets and other methods.
[0058] S3. Feed Japanese freshwater prawn larvae different feeds at different growth stages and add supplementary feeds; Specifically, the growth stages of Japanese prawn larvae include stages I-IV, V-VII, and VIII-larval stage, and stages II-IV, V-VII, and VIII-larval stage.
[0059] During stages II-IV, shrimp chips and spirulina powder filtered through a 100-mesh sieve were fed. The particle size of the shrimp chips and spirulina powder was ≤150μm, the mass ratio of shrimp chips to spirulina powder was 10:1, and the feeding amount was 0.1-0.15g / 10,000 shrimps, fed once every 3 hours. During stages V-VII, artificial pelleted feed with added vitamin C was fed through a 100-mesh sieve. The feed particle size was ≤250μm, and the amount of added vitamin C in the feed was 2.5g / kg.
[0060] During stages IV-V, the aeration intensity was reduced and artificial substrates were used for shading to reduce the mortality rate of shrimp larvae due to collisions.
[0061] During the VIII-larval stage, feed cladocerans with povidone-iodine disinfected feed at a rate of 0.8-1.2 g / 10,000 cladocerans. Before use, the povidone-iodine disinfected cladoceran feed should be soaked in clean water for 15 minutes at a rate of 0.35 g / kg.
[0062] During the IX-larval stage, the peak ammonia nitrogen level was monitored (controlled to ≤0.60 mg / L), and natural feed was provided by microorganisms (proteobacteria ≥70%) on the surface of porous carriers.
[0063] In this embodiment, the metamorphosis rate was observed using a dissecting microscope. When the metamorphosis rate of larvae reached 80%, they were considered to have entered the next developmental stage. The same sample processing and collection methods as in Example 1 were used to statistically analyze the survival rates of the fourth, fifth, and ninth stages of the zoea larvae of the Japanese giant river prawn. The comparison results of the survival rates of the zoea larvae in stages IV-V and IX of the Japanese giant river prawn are shown in Table 2. According to the above data, compared with Example 1, the coastal area has higher water temperature stability, and the composite uniform biofilm formation effect is slightly better. The survival rate in the fourth and fifth stages is 1% higher than that in Example 1, and the survival rate in the ninth stage is 2% higher.
[0064] In this embodiment, when using a composite bacterial solution to inoculate a porous carrier to form an artificial substrate, the survival rate of the experimental group of *Macrobrachium nipponense* larvae increased by 3% compared to the control group in the fourth stage; in the fifth stage, the survival rate increased by 12% compared to the control group; and in the ninth stage, the survival rate increased by 19% compared to the control group. This indicates that in coastal areas, using a composite bacterial solution for biofilm formation is more effective in improving the survival rate of *Macrobrachium nipponense* larvae compared to using natural water biofilm formation in North China.
[0065] Example 3: A Method for Improving the Survival Rate of Zoaniopsis larvae of the Japanese giant freshwater prawn based on Bacterial-Membrane Synergy In this embodiment, the experimental site is an inland freshwater seedling nursery.
[0066] S1. Place the artificial substrate in a natural lake water body (Class III surface water) and perform biofilm formation. Under the condition of water temperature of 28℃, the biofilm will form for 15 days, so that a bacterial community dominated by Proteobacteria will form on the artificial substrate, with the proportion of Proteobacteria ≥60%. S2. The artificial substrate, after being soaked in natural water, was placed in three 5m*5m*1.5m seedling ponds. These ponds were located within a seedling workshop, a brick-concrete structure with a fiberglass roof for better lighting. The workshop was equipped with a complete water inlet / outlet, air supply, and lighting system. The artificial substrate was spaced 30cm apart in each pond, serving as the experimental group. Three other identical ponds were used as the control group without artificial substrate. The same number of Japanese giant freshwater shrimp larvae were then introduced into each pond, and water quality and temperature were controlled. In terms of water quality management and temperature control, each seedling pond undergoes daily water exchange via expanded rubber cotton filtration at 20% capacity, maintaining a constant water temperature of 28±1℃ and a pH of 8.12. Aeration stones with a mesh size of 40 are then added, and the air volume is adjusted to a microbubble state to ensure dissolved oxygen levels in the seedling pond are ≥5mg / L. Light intensity is then controlled to ≤500 lux using shading nets and other methods.
[0067] S3. Feed Japanese freshwater prawn larvae different feeds at different growth stages and add supplementary feeds; Specifically, the growth stages of Japanese prawn larvae include stages I-IV, V-VII, and VIII-larval stage, and stages II-IV, V-VII, and VIII-larval stage.
[0068] During stages II-IV, shrimp chips and spirulina powder filtered through a 100-mesh sieve were fed. The particle size of the shrimp chips and spirulina powder was ≤150μm, the mass ratio of shrimp chips to spirulina powder was 10:1, and the feeding amount was 0.1-0.15g / 10,000 shrimps, fed once every 3 hours. During stages V-VII, artificial pelleted feed with added vitamin C was fed through a 100-mesh sieve. The pellet size of the feed was ≤250μm, and the amount of added vitamin C in the feed was 3g / kg.
[0069] During stages IV-V, the aeration intensity was reduced and artificial substrates were used for shading to reduce the mortality rate of shrimp larvae due to collisions.
[0070] During the VIII-larval stage, feed cladoceran feed disinfected with povidone-iodine at a rate of 0.8-1.2 g / 10,000 cladocerans. Before use, the povidone-iodine-disinfected cladoceran feed should be soaked in clean water for 20 minutes at a rate of 0.5 g / kg.
[0071] During the IX-larval stage, the peak ammonia nitrogen level was monitored (controlled to ≤0.60 mg / L), and natural food was provided by microorganisms on the surface of the porous carrier.
[0072] In this embodiment, the metamorphosis rate was observed using a dissecting microscope, with a metamorphosis completion standard of 80%. The same sample processing and collection methods as in Example 1 were used to statistically analyze the survival rates of the fourth, fifth, and ninth stages of the zoea larvae of the Japanese giant freshwater prawn. The comparison results of the survival rates of the zoea larvae in stages IV-V and IX of the Japanese giant freshwater prawn are shown in Table 3. According to the above data, compared with Example 1, the inland water hardness is lower, the microbial metabolic activity is slightly reduced, the survival rate in the fourth stage is 2% lower than that in Example 1, the survival rate in the fifth stage is 3% lower than that in Example 1, and the survival rate in the ninth stage is 4% lower than that in Example 1.
[0073] In this embodiment, when natural biofilm formation was carried out using inland natural water bodies, the survival rate of Japanese giant freshwater prawn larvae differed by 1% in the fourth stage compared to the stage without artificial substrate; in the fifth stage, the survival rate of Japanese giant freshwater prawn larvae increased by about 10%; and in the ninth stage, the survival rate of Japanese giant freshwater prawn larvae increased by about 15%.
[0074] In Examples 1-3, the survival rates of Japanese giant freshwater prawn larvae in the experimental groups at stages 4, 5, and 9 are shown in Table 4. According to the data above, in stages IV, V, and IX, the survival rate of Japanese giant prawn larvae was lowest in an inland freshwater seedling nursery compared to the seedling workshop of a certain aquaculture company in North China and a certain aquaculture workshop in a coastal area. Conversely, the survival rate of Japanese giant prawn larvae was highest in a certain aquaculture workshop in a coastal area, followed by the seedling workshop of a certain aquaculture company in North China. This indicates that the water conditions in different regions have an impact on the survival rate of Japanese giant prawn larvae, with coastal areas being relatively more suitable.
[0075] The above provides a detailed description of a method for improving the survival rate of zoea larvae of the Japanese giant freshwater prawn based on a bacterial-membrane synergistic approach. The specific embodiments described are merely illustrative of the method and its core principles. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims.
[0076] It should be noted that: for experimental steps or conditions not specified in the examples, the procedures and conditions described in conventional experimental procedures in the literature of this art can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.
[0077] The above examples are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the scope of protection of the present invention.
Claims
1. A method for improving the survival rate of zoea larvae of the Japanese giant shrimp based on bacterial-film synergy, characterized in that, Includes the following steps: S1. Place the porous carrier in water and perform biofilm formation for 10-16 days to obtain a porous carrier loaded with microorganisms. S2. Place the porous carrier loaded with microorganisms into the seedling device, then release the Japanese giant freshwater shrimp larvae into the seedling device, and manage the water quality and temperature. S3. Feed Japanese prawn larvae different feeds at different growth stages and add supplementary feeds.
2. The method according to claim 1, characterized in that, In step S1, the porous carrier includes at least one of porous carbon fiber carrier, porous polyethylene biological carrier, bioceramic, sponge, coral stone, volcanic rock, biological rope, biological ball, porous brick, porous tile, porous polyester fiber material, and porous nylon fiber material.
3. The method according to claim 1, characterized in that, In step S1, when performing the biofilm formation operation, the porous carrier is placed in a natural water body and the biofilm is formed for 14-16 days at a water temperature of 25-30℃.
4. The method according to claim 3, characterized in that, When the porous carrier is attached to a biofilm for 14-16 days, a community of Proteobacteria will form on the porous carrier, with the number of Proteobacteria being ≥60%.
5. The method according to any one of claims 1-4, characterized in that, In step S1, when performing the biofilm formation operation, the porous carrier is placed in the composite bacterial solution and the biofilm is formed for 9-11 days at a water temperature of 25-28℃.
6. The method according to claim 5, characterized in that, The compound bacterial solution includes at least two of the following: nitrifying bacteria, Bacillus, lactic acid bacteria, denitrifying bacteria, photosynthetic bacteria, Vibrio antagonistic bacteria, and EM bacteria.
7. The method according to any one of claims 1-4, characterized in that, In step S2, when managing water quality and controlling temperature, 20-25% of the water is changed daily, and the water temperature is kept constant at 28±1℃.
8. The method according to any one of claims 1-4, characterized in that, In step S2, when managing water quality and controlling temperature, air stones are added and the air volume is adjusted to a microbubble state, with dissolved oxygen ≥5mg / L.
9. The method according to any one of claims 1-4, characterized in that, In step S3, the different growth stages of Japanese giant freshwater prawn larvae include stages I-IV, V-VII, and VIII-larval stage. During stages II-IV, V-VII, and VIII-larval stage, different feeds and supplements are provided respectively. During stages II-IV, shrimp chips and spirulina powder are fed at a rate of 0.1-0.15 g / 10,000 prawns, once every 2-4 hours. During stages V-VII, artificial pellet feed supplemented with vitamin C is provided. During the VIII-larval stage, povidone-iodine-treated cladoceran feed is provided.
10. The method according to claim 9, characterized in that, During stages IV-V, the aeration intensity is reduced and a porous carrier loaded with microorganisms is used for shielding; and / or, during stage IX-larval shrimp, the peak ammonia nitrogen level is monitored to be ≤0.60 mg / L, and natural food is provided by microorganisms on the surface of the porous carrier.