A method for cultivating macrobrachium rosenbergii fry based on resource processing of apple snails

Abstract

The present application relates to the field of resource processing of apple snails and aquaculture technology, and particularly relates to a method for cultivating macrobrachium rosenbergii fry based on resource processing of apple snails. The method comprises the following steps: sequentially performing multi-stage purification on the captured apple snails through temporary breeding emptying, circulating micro-flow water flushing and EM bacteria liquid soaking, then crushing the apple snails into minced meat, adding salt and / or organic acid, mixing the minced meat with plant raw materials rich in vitamins and vitamin mineral premixes in proportion, and extruding or molding the mixture into apple snail soft block baits which are not easy to be soaked and dispersed by using a hydrophilic gel adhesive. In the fry cultivation pond, the soft block baits are precisely fed in proportion and at a specified time period together with the feed, and the feeding amount and water change are dynamically adjusted in combination with water quality indexes, so as to improve the gonadal development and reproductive performance of the macrobrachium rosenbergii fry, stabilize the water quality and reduce the cost of baits.

Description

Technical Field

[0001] This invention relates to the fields of golden apple snail resource utilization and aquaculture technology, and particularly to a method for breeding giant freshwater prawns based on golden apple snail resource utilization. Background Technology

[0002] The giant freshwater prawn (Macrobrachium rosenbergii) is a large, economically important freshwater shrimp species characterized by rapid growth, large size, excellent meat quality, and high economic value. It is one of the dominant species in traditional aquaculture areas of my country, such as the Yangtze River Delta and Pearl River Delta, and its farming scope has gradually expanded to inland regions in recent years. With the continuous expansion of aquaculture scale, broodstock cultivation has become a core link in seedling production, as its quality directly affects seedling survival rate, growth performance, and subsequent aquaculture benefits. However, at present, the feeding of giant freshwater prawn broodstock is still mainly based on experience, lacking specialized feeds designed for the gonadal development needs of broodstock and standardized feeding processes. This leads to problems such as poor broodstock health, uneven gonadal development, and unstable egg-carrying and hatching rates, which to some extent restricts the further development of the giant freshwater prawn industry.

[0003] In existing technologies, there has been some research on feeding patterns for the cultivation of giant freshwater prawns. For example, Chinese invention patent CN107637553A discloses a feeding method for giant freshwater prawns, which uses a combination of Daphnia rubra, freshwater snails, and a special formulated feed for giant freshwater prawns at different growth stages: in the early stage of cultivation, Daphnia rubra and formulated feed are the main feeds; in the middle stage, a combination of Daphnia rubra, freshwater snails, and formulated feed is used; and in the later stage, freshwater snails are used in combination with formulated feed to improve the growth rate and marketable yield of giant freshwater prawns. By optimizing the ratio of natural feed (Daphnia rubra and freshwater snails) to formulated feed, this method has achieved good results in improving the growth performance and yield of adult prawns. However, this technical solution is mainly aimed at commercial prawn farming and does not design a special feed formula and feeding system for the broodstock stage. The freshwater snails used are also conventional freshwater snails, and it does not involve the use of the invasive species Pomacea canaliculata as a low-cost and advantageous protein source, nor does it involve systematic purification and deep processing of snails to take into account the comprehensive needs of feed safety, water quality stability, and palatability.

[0004] Currently, traditional control methods for golden apple snails mainly rely on manual collection, physical trapping, and chemical and drug-based extermination. Although these methods can reduce snail density to some extent, they generally involve high labor intensity, high costs, and potential toxicity or secondary pollution to the environment and associated aquaculture species, making it difficult to support the needs of large-scale, long-term green control.

[0005] With the promotion of green aquaculture and circular agriculture concepts, transforming the golden apple snail from a "pest" into a protein feed for aquaculture and utilizing it as a resource has gradually become a focus of attention in the industry. Existing technologies for the feed utilization of the golden apple snail resource itself mainly focus on processing it into a protein source for fish and other aquatic animals. For example, Chinese invention patent CN104757318A discloses a fish feed with added golden apple snail muscle powder. The collected golden apple snails are rinsed with tap water, temporarily held, boiled in boiling water for 2-3 minutes, and the cephalopod muscles are removed and the internal organs are removed. After two rounds of crushing and drying, golden apple snail muscle powder with a particle size of 50-200 mesh is obtained. This powder is then mixed with fish meal, soybean meal, fish oil, blood meal, wheat bran, multivitamin and mineral premix, salt, and binders to form pelleted fish feed. This achieves partial replacement of fish meal with golden apple snail muscle powder, reducing feed costs and achieving good fish growth results. This technology demonstrates the feasibility of using golden apple snails as a protein source for aquatic feed. However, it is positioned as a general fish feed or experimental fish feed, mainly using dry powder to formulate conventional pellet feed. It has not been structurally designed for the feeding habits of crustacean broodstock shrimp towards soft pellet feed, nor has it considered the risks of parasites, pathogens, and environmental pollutants that may arise from the complex origin of golden apple snails. It still has shortcomings in purification, decontamination, and water quality-friendly control. Furthermore, it does not involve the synergistic formulation of plant-based raw materials such as carrots with golden apple snail meat paste to form "soft pellet feed" to balance vitamin supplementation, palatability, and stability in water that does not easily disintegrate over a long period of time.

[0006] In addition, existing technologies also include methods for using golden apple snails in combination with plant-based ingredients as feed for aquatic animals such as turtles and tortoises. For example, Chinese patent CN104585484A discloses a feed for preventing and treating parotitis in soft-shelled turtles and its preparation method. This feed includes golden apple snails, corn, pumpkin, snails, locusts, salt, and various traditional Chinese medicine preparations. It is prepared through steps such as drying, crushing, mixing, and granulation, which utilizes the nutritional value of animal-based ingredients such as golden apple snails and combines them with traditional Chinese medicine components to improve the disease resistance of soft-shelled turtles. However, this technology focuses on the prevention and treatment of specific diseases and nutritional health care, targeting reptiles such as soft-shelled turtles, and is not designed for the biological characteristics and reproductive needs of giant freshwater prawns. Its raw material forms are mainly dry powder and granules, and it does not involve multi-stage water purification and EM bacteria biological treatment of golden apple snails, or the use of hydrophilic gel binders to construct soft bait blocks that remain stable in water for 2-4 hours.

[0007] In the areas of water quality control and microecological preparations, EM (Effective Microorganisms) products are widely used in existing technologies to improve the aquatic environment of aquaculture. For example, Chinese invention patent CN109971682A discloses an EM liquid for aquaculture, its preparation method, and its application. This EM liquid is composed of various probiotics such as Lactobacillus acidophilus, Lactobacillus plantarum, Enterococcus faecalis, Saccharomyces cerevisiae, Bacillus coagulans, and Clostridium butyricum. After fermentation, it can be sprayed into the water at a certain ratio to quickly decompose organic pollutants in the water, reduce ammonia nitrogen and nitrite, inhibit the growth of pathogens, improve the bacterial and algal community environment of the water, and can be mixed with aquatic feed at a ratio of 1-3 wt% to improve the immunity and growth rate of aquatic animals. This technology demonstrates the significant role of EM bacteria in water purification and microecological regulation in aquaculture. However, its focus is on the preparation of the EM solution itself and its general application in aquaculture water. It does not design a special purification process for the safe pretreatment of exogenous animal feed (especially from the invasive species golden apple snail), nor does it organically combine the EM soaking step with physical rinsing of circulating micro-flow water, temporary holding and emptying, etc., to build a complete solution for the "from live purification to feed formation" of golden apple snail raw materials.

[0008] In summary, existing technologies have shortcomings in the following aspects: First, feeding techniques for giant freshwater prawns are mostly focused on the commercial prawn farming stage, lacking targeted research on the nutritional needs of broodstock, especially during the critical period of gonadal development. They still largely rely on empirical combinations such as "formulated feed, fish / snails / shellfish," resulting in a diverse range of feed types and large fluctuations in nutritional levels, making it difficult to consistently improve gonadal index, egg-carrying rate, and hatching rate. Second, although several patents have disclosed the use of golden apple snail muscle powder or golden apple snail powder to replace fishmeal as a protein source for aquatic feed, they generally employ a high-temperature cooking-drying-pulverizing-granulation process, primarily targeting fish or experimental fish. This approach lacks sufficient attention to the purification and safety control of golden apple snails and fails to address the specific needs of crustaceans like giant freshwater prawns for soft, blocky, easily digestible, and non-dispersible feed. Furthermore, there is a lack of a soft, blocky feed structure design that synergistically constructs "low-cost golden apple snail raw materials, vitamin-rich plant-based raw materials, vitamin and mineral premixes, and hydrophilic gel binders." Third, existing EM products are mostly used for overall water body improvement or as feed additives, and have not been applied to the pre-treatment of high-risk raw materials such as golden apple snails to systematically reduce the load of pathogens and metabolic waste inside and outside the snails through multi-stage synergistic purification. Furthermore, they have not been integrated with specific feeding ratios, water quality threshold control, and nutritional strategies for different reproductive stages of broodstock shrimp to form an integrated technical system.

[0009] In actual production, giant freshwater prawn (Macrobrachium rosenbergii) broodstock farms typically face the following common problems: First, there is a lack of inexpensive, nutritionally balanced, controllable, and palatable animal-based feed specifically for broodstock. Commonly used feeds, such as frozen ribbonfish, are easily dissolved in water after cooking, rapidly polluting the water. Furthermore, uncooked feeds pose a risk of carrying pathogens and parasites. Ordinary snail meat is expensive to purchase and comes from scattered sources, posing food safety risks. Second, while golden apple snails are widespread in southern rice-growing areas, have low purchase costs, and are meaty, as an invasive species, they may accumulate various pollutants and pathogens. Simply washing or briefly boiling them before feeding them directly cannot meet the dual requirements of feed hygiene and water quality stability for broodstock cultivation. Thirdly, in pond management, feeding systems are mostly adjusted based on experience, lacking a scientific feeding strategy that links water quality indicators (ammonia nitrogen, nitrite, dissolved oxygen, etc.) with the gonadal development stage of broodstock shrimp. This can easily lead to overfeeding causing water environment deterioration, or underfeeding causing malnutrition and decreased spawning performance of broodstock shrimp.

[0010] Therefore, based on existing technologies, there is an urgent need to propose a method for producing a soft, non-disintegrating feed block that uses golden apple snails as the main animal-based raw material, combines multi-stage purification and safe treatment processes, and mixes them with vitamin-rich plant-based raw materials and vitamin-mineral premixes in a specific ratio. This feed block is then bound with a hydrophilic gel binder and remains stable in water for 2-4 hours. Simultaneously, a method for raising broodstock shrimp based on optimized animal-based feed ratios and feeding times is needed. This method aims to fully utilize low-cost golden apple snail resources while achieving efficient breeding of giant freshwater prawn broodstock, rapid gonad development, and long-term water quality stability. No identical or similar technical solutions to this invention have been found in existing publicly available literature. Summary of the Invention

[0011] The purpose of this invention is to address the problems of high feed costs, unstable feed sources, insufficient nutritional targeting, and easy water quality deterioration in the existing cultivation of giant freshwater prawn broodstock. This invention proposes a special cultivation method for broodstock broodstock based on the resource-based treatment of golden apple snails. This method involves multi-stage purification and safety treatment of golden apple snails, and synergistic formulation with vitamin-rich plant materials, vitamin and mineral premixes, and hydrophilic gel binders to prepare stable, non-disintegrating, and palatable golden apple snail soft feed in water. Combined with an optimized feeding system, this achieves comprehensive optimization of nutrient supply, water quality control, and reduced cultivation costs for giant freshwater prawn broodstock.

[0012] To achieve the above objectives, the present invention adopts the following technical solution:

[0013] A method for breeding giant freshwater prawns based on the resource utilization of golden apple snails, the method comprising the following steps:

[0014] S1. Place the captured live golden apple snails in purified water and use circulating micro-flow water for physical rinsing, followed by biological purification by soaking in EM bacterial solution.

[0015] S2. The purified golden apple snails are put into a crushing device for crushing and then screened through a screen to obtain snail meat paste. Salt and / or organic acids are added at 1-3% of the weight of the golden apple snail meat.

[0016] S3. Mix snail meat paste with vitamin-rich plant-based raw materials and vitamin and mineral premix in a mass ratio of (3-6):(0.5-2):(0.1-0.5), and further add a hydrophilic gel binder at 0.5-2.0% of the total mass of the mixture. Then, extrude or mold it into soft apple snail bait with a smooth surface that does not easily disintegrate in water for 2-4 hours.

[0017] S4. In the rearing pond of giant freshwater prawns, the golden apple snail soft bait is used in combination with the conventional giant freshwater prawn broodstock feed, so that the animal feed accounts for 20-60% of the total daily feed for the broodstock, of which the golden apple snail soft bait accounts for 60-90% of the animal feed mass, and is fed evenly in the evening and at night.

[0018] Preferably, in step S1, the golden apple snails are rinsed with circulating micro-flow water at a pressure of 0.2–0.4 MPa and a flow rate of 5–10 L / min for 30–60 min; after rinsing, EM bacterial solution with an effective live bacteria count ≥1×10⁻⁶ is added at a volume ratio of 1:500 to 1:1000. 8 Soak CFU / mL EM bacterial solution at 25-30℃ for 2-4 hours.

[0019] Preferably, the EM bacterial solution is a compound probiotic system composed of lactic acid bacteria, yeast, and photosynthetic bacteria. During preparation, the above-mentioned bacterial strains are first mixed in a mass ratio of 1:1:1, and then activated with 3-5% (by mass) brown sugar water for 18-36 hours. After activation, the effective viable bacteria count is not less than 1×10⁻⁶. 8 The concentration of CFU / mL is then added to purified water at a volume ratio of 1:500-1:1000 for soaking treatment.

[0020] Preferably, before the S1 multi-stage synergistic purification treatment, a temporary holding and emptying step is also included: the captured golden apple snails are temporarily held in clean water for 48-72 hours without being fed any feed, and the dissolved oxygen is maintained at ≥5mg / L, so as to promote the golden apple snails to fully empty their intestinal contents, reduce the endogenous pollutant load, and then enter the flushing and EM purification process.

[0021] Preferably, in step S2, the crushing device is a spiral or hammer crusher, and the material temperature is controlled to be ≤40℃ during the crushing process to reduce nutrient loss; the screen mesh size is 0.5-2.0mm, the organic acid is selected from citric acid, lactic acid, acetic acid or any combination thereof, the amount of salt added is 1.0-2.0% of the weight of the golden apple snail meat, and the amount of organic acid added is 0.1-0.5% of the weight of the golden apple snail meat.

[0022] Preferably, in step S3, the hydrophilic gel binder is composed of gelatin, sodium alginate, starch paste, or a combination thereof; the plant-based raw material includes one or more of carrots, pumpkins, pumpkin leaves, spinach, and laver; the vitamin and mineral premix contains 10,000–30,000 IU / kg of vitamin A, 100–300 mg / kg of vitamin E, 0.6–1.2% of total phosphorus, and 1.0–2.0% of total calcium; and the resulting golden apple snail soft bait has a crude protein content of 35–45% and a crude fat content of 6–10%.

[0023] Preferably, step S3 further includes adding a probiotic preparation and / or a compound enzyme preparation to the mixture at 0.05-0.5% of the total mass of the mixture. The probiotic preparation includes lactic acid bacteria, Bacillus, or a combination thereof, and the compound enzyme preparation includes one or more of protease, amylase, and cellulase, in order to improve the digestibility and utilization of the soft bait from the golden apple snail and reduce the impact of residual bait on water quality.

[0024] Preferably, during the feeding process described in S4, the water quality parameters of the broodstock rearing pond are monitored and the feeding and water exchange are adjusted according to the water quality. The dissolved oxygen is maintained above 5 mg / L, the ammonia nitrogen concentration is controlled below 0.5 mg / L, and the nitrite nitrogen concentration is controlled below 0.15 mg / L. When any indicator exceeds the limit, the amount of animal feed is reduced by 10-30% and the water exchange ratio is increased by 10-30%.

[0025] Preferably, the feeding times in S4 are set to any 2 to 3 time periods, 1 hour before sunset, 1 to 2 hours after sunset, and 1 hour before dawn, with the feeding amount for each feeding being 1 to 3% of the total body weight of the broodstock during that time period; the proportion of plant-based raw materials is increased in the early stage of ovarian development to prevent overfeeding, and the proportion of soft snail bait is increased in the pre- and post-mating stages to promote rapid gonadal development and increase the egg-carrying rate.

[0026] As a preferred method, the weight growth rate, gonad index, egg-carrying rate, and hatching rate of giant freshwater prawns before and after implementing the method were used as evaluation indicators. Compared with the control group fed with ribbonfish meat or ordinary snail meat under the same total feeding conditions, the gonad index of the golden apple snail soft bait group increased by 10-30%, the egg-carrying rate increased by 5-20%, and the average concentration of total ammonia nitrogen in the culture water decreased by 20-40%.

[0027] This invention achieves several synergistic effects by constructing an integrated technical system encompassing "multi-stage purification of golden apple snails, quantitative seasoning and acidification, vitamin and plant-based raw material fortification, hydrophilic gel soft block molding, and precise feeding under water quality threshold constraints." Firstly, the multi-stage synergistic purification process—including temporary holding and emptying, physical rinsing with circulating micro-flow water, and soaking in EM (Effective Microorganisms) solution—significantly reduces the metabolic waste, parasites, and pathogen load within and outside the golden apple snails, thus significantly improving the safety of the snail meat paste. Secondly, the addition of appropriate amounts of salt and organic acids in step S2 further inhibits harmful microorganisms, improves the flavor and palatability of the snail meat paste, and stabilizes the protein structure and reduces nutrient loss to a certain extent. Thirdly, the introduction of plant-based raw materials rich in carotenoids and vitamins, such as carrots, pumpkins, and pumpkin leaves, along with vitamin and mineral premixes, in step S3 at specific mass ratios makes the amino acid profile, fat-soluble vitamins, and calcium and phosphorus mineral ratios of the soft block bait more suitable for the gonadal development needs of giant freshwater prawns. This, combined with gelatin and alginic acid, further enhances the benefits. The synergistic effect of hydrophilic gelling binders such as sodium and starch paste forms a soft, blocky feed structure that remains stable in water for 2-4 hours without easily disintegrating. This satisfies the shrimp's preference for soft, blocky animal feed while significantly reducing feed debris leaching and sudden increases in organic load, mitigating the risk of water quality deterioration at its source. Furthermore, by limiting the proportion of animal feed, the percentage of apple snail soft feed, and the feeding time (concentrated in the evening and at night, with dynamic adjustments to feeding amount and water exchange ratio based on water quality indicators) in S4, the shrimp's feeding throughout the breeding process is ensured... During the feeding cycle, it can obtain a stable and easily digestible supply of high-quality animal protein and vitamins, while avoiding the accumulation of ammonia nitrogen and nitrite caused by overfeeding. Experiments have shown that, under the same total feeding amount, the golden apple snail soft block bait group of this invention can increase the gonad index of giant freshwater prawn broodstock by about 10-30% and the egg-carrying rate by about 5-20%, while reducing the average concentration of total ammonia nitrogen in the cultivation water by about 20-40%, thus achieving a comprehensive optimization of broodstock reproductive performance, water environment stability and feed cost control. Detailed Implementation

[0028] The technical solutions in the embodiments 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 protection scope of the present invention.

[0029] I. Terminology and Test Methods

[0030] 1. Temporary rearing and emptying: This refers to placing newly captured golden apple snails in clean water without feeding them any food, and allowing them to empty their intestinal contents and reduce metabolic products through a 24-72 hour rearing process.

[0031] 2. Circulating micro-flow water: This refers to the stable, low-velocity water flow formed in the purification tank by a circulating water pump, with the flow rate controlled at 5-10 L / min. Combined with an aeration device, this creates a weak flow environment for physical rinsing and removing dirt and shed metabolites from the surface of the golden apple snail.

[0032] 3. EM bacterial solution: In this embodiment of the invention, a compound probiotic system composed of lactic acid bacteria, yeast, and photosynthetic bacteria is used, and the effective live bacteria count after activation is not less than [amount missing]. .

[0033] 4. Gonadal Index (GSI): Calculated using the following formula:

[0034] ;

[0035] in Gonadal mass (g) The value is the individual weight (g) of the giant freshwater prawn.

[0036] 5. Determination of ammonia nitrogen, nitrite nitrogen and dissolved oxygen: The determination was carried out according to national or industry standard methods such as "Water Quality - Determination of Ammonia Nitrogen", "Water Quality - Determination of Nitrite", and "Water Quality - Determination of Dissolved Oxygen". In this example, a commercially available water quality reagent kit and a benchtop photometer were used for detection.

[0037] 6. Stability of soft apple snail bait in water: Weigh a certain amount of soft bait and put it into still water. After a set time (2h, 4h), take it out, remove the surface water and weigh it. Calculate the percentage of the remaining mass to the initial mass to evaluate the degree of foaming and disintegration.

[0038] II. General Description

[0039] This invention provides a method for breeding giant freshwater prawns based on the resource utilization of golden apple snails. The method involves "temporarily suspending and emptying the captured golden apple snails, physical rinsing with circulating micro-flow water, biological purification by soaking in EM bacterial solution, crushing and seasoning with acid salts, nutritional fortification with plant-based raw materials and vitamin and mineral premix, hydrophilic gel soft block molding, and precise feeding under water quality threshold constraints" to achieve the preparation and application of golden apple snail soft block feed specifically for broodstock prawns.

[0040] To verify the effectiveness of the technical solution of the present invention, multiple embodiments (E1-E3) and multiple comparative examples (C1-C3) were set up for comparative experiments. The embodiments are used to illustrate that the same technical effect can be achieved within different optional parameter ranges, while the comparative examples are used to demonstrate that when the key steps or parameter combinations of the present invention are missing, the reproductive performance and water quality control effect of the giant freshwater prawn broodstock are significantly reduced, thereby highlighting the superiority of the solution of the present invention.

[0041] III. Example 1: Standard Process Flow

[0042] 1. Capture and temporary holding of golden apple snails

[0043] Approximately 500 kg of live golden apple snails were manually captured from a rice paddy severely affected by them. After removing obviously injured, dead, and rotting individuals, the snails were released into a 10m... 3 The water source for the temporary holding tank is clean surface water from nearby, which is used directly after sand filtration; the holding density is controlled at 50 kg / m³. 3 The snails were temporarily held for 60 hours without being fed. One-third of the water was replaced every 12 hours, and dissolved oxygen was maintained at 5–7 mg / L. This temporary holding allowed the snails to empty their intestinal contents, reducing the load of endogenous pollutants.

[0044] 2. Multi-stage collaborative purification

[0045] After the temporary holding period ends, the golden apple snails are removed from the holding tank and placed in a 5m... 3 The water depth in the purification tank is controlled at approximately 0.2m.

[0046] 1) Circulating micro-flow water flushing:

[0047] A centrifugal pump with a rated power of 1.5kW is used to form a closed-loop circulation, and a diversion nozzle is installed at the pipeline outlet; the system pressure is adjusted to 0.30MPa, and the water flow rate is about 8L / min; the flushing time is set to 45min; during the flushing process, the micro-aeration device is turned on to maintain dissolved oxygen ≥5mg / L in order to reduce the stress and death of snails.

[0048] 2) EM bacterial solution activation and soaking:

[0049] Lactic acid bacteria, yeast, and photosynthetic bacteria were mixed in a 1:1:1 ratio and placed in prepared brown sugar water (4% by mass). The mixture was activated at 30°C for 24 hours. After activation, the effective viable bacteria count reached approximately 1 × 10⁻⁶. 8 CFU / mL; After draining the rinsing wastewater, pour fresh clean water into the purification tank to a depth of approximately 0.25m; add the above-mentioned activated EM bacterial solution to the purification tank at a volume ratio of 1:800, so that the effective viable bacteria count in the water is close to 1×10⁻⁶. 5 ~10 6 The concentration of CFU / mL was controlled at 28℃, the soaking time was 3 hours, and dissolved oxygen was maintained at 5–7 mg / L with slight aeration. Random samples were taken before and after purification to detect Aeromonas hydrophila load and typical pesticide residues, verifying the purification effect.

[0050] 3. Crushing and salt / acid seasoning treatment

[0051] After purification, the whole apple snails (without breaking the shell or removing the meat) are fed into a screw crusher via an elevator. The crusher is equipped with a 2mm screen aperture to ensure that the crushed mixture can pass through the screen smoothly. During the crushing process, the feed rate and screw speed are controlled to ensure that the material temperature does not exceed 40℃. The crushed material is then screened by a vibrating screen to remove large shell pieces, resulting in snail meat paste with a particle size ≤2mm (containing a small amount of fine shell powder, connective tissue, etc.).

[0052] Take 100 kg of minced snail meat, add 1.5 kg of salt (1.5 wt%) and 0.2 kg of citric acid (0.2 wt%), and mix thoroughly in a stainless steel mixing tank. The salt improves palatability and creates a slight osmotic pressure for sterilization, while the citric acid adjusts the pH to the range of 5.5–6.0, inhibiting the growth of some bacteria and improving the flavor of the minced meat. The seasoning and mixing time is approximately 15 minutes.

[0053] 4. Preparation of soft bait for golden apple snails

[0054] (1) Formulation design

[0055] This embodiment uses the following mass percentage formulation (calculated on a wet basis):

[0056] Snail meat paste: 60%

[0057] Finely chopped carrots: 12%

[0058] Finely chopped pumpkin: 8%

[0059] Pumpkin leaf powder (pre-dried and ground to 80 mesh): 4%

[0060] Vitamin and mineral premix: 2%

[0061] Gelatin solution (10% solids): 8%

[0062] Sodium alginate solution (5% solids content): 4%

[0063] Probiotic preparation (mixture of lactic acid bacteria and Bacillus): 0.5%

[0064] Compound enzyme preparation (protease + amylase + cellulase): 0.5%

[0065] Adjust the water content to approximately 65% ​​with an appropriate amount of drinking water.

[0066] The above ratio, converted to the mass ratio of snail meat paste: plant-based raw materials: mineral premix, is approximately: The ratio is in the range of (3~6):(0.5~2):(0.1~0.5); the total solids of gelatin + sodium alginate account for about 1.0% of the wet mixture mass, which is within the range of 0.5~2.0% for hydrophilic gel binders.

[0067] The vitamin and mineral premix contains approximately 20,000 IU / kg of vitamin A, approximately 200 mg / kg of vitamin E, approximately 0.9% total phosphorus, and approximately 1.5% total calcium. The probiotic preparation contains no less than [amount missing]. .

[0068] (2) Mixing and molding

[0069] First, wash and slice the carrots and pumpkin, then chop them into 2-3mm pieces using a vegetable chopper. Dry the pumpkin leaves with hot air at 60℃ until the moisture content is about 10%, then grind them to 80 mesh. Add the snail meat paste, plant-based ingredients, vitamin and mineral premix, probiotics, and compound enzyme preparation to a twin-shaft paddle mixer in the above proportions. Dry mix for 5 minutes, then slowly add the gelatin solution and sodium alginate solution, and continue mixing for 10 minutes until the mixture is in a uniform, moist, and plastic state.

[0070] The mixture is fed into an extrusion-cutting machine, using a 10mm diameter round die to extrude strips, which are then cut into cylindrical soft blocks approximately 10mm long by a cutting mechanism. The formed soft blocks are then... Pre-dry the surface under hot air conditions for 1 hour to allow the outer surface to shrink slightly and form a thin film, while the inside remains soft and moist, thereby improving structural stability and palatability in water.

[0071] (3) Nutritional component testing

[0072] Samples of the prepared soft bait were dried at 105℃ and their moisture content was determined. Then, crude protein, crude fat, and crude ash were determined using conventional methods. The results showed that:

[0073] Crude protein: Approximately 40.2% (dry basis)

[0074] Crude fat: Approximately 7.8% (dry basis)

[0075] Coarse ash content: Approximately 11.5% (dry basis)

[0076] It meets the requirements of 35-45% crude protein and 6-10% crude fat.

[0077] (4) Stability test in water

[0078] Simulating the water quality conditions (water temperature) of aquaculture ponds In a glass water tank with dissolved oxygen of 6 mg / L and a static water volume of 20 L, 100 g of soft bait was added. The bait was removed after 2 hours and 4 hours, drained, and weighed. The results are as follows:

[0079]

[0080] Within 4 hours, the soft bait basically maintains its block shape, with a small amount of edge detachment and no obvious debris deposition, meeting the requirement that it "does not easily disintegrate in water within 2 to 4 hours".

[0081] 5. Breeding and Feeding of Giant Freshwater Prawns

[0082] (1) Pond conditions and stocking

[0083] Three cement ponds, each 0.5 mu in area and with an average depth of 1.5 m, were selected. Each pond was equipped with a microporous aeration system, bottom drainage, and automatic water filling facilities, with a small amount of sediment at the bottom. Each pond was stocked with giant freshwater prawns at a female-to-male ratio of approximately 2:1, with a total stocking density of 150 kg / mu and initial individual weights of approximately 40–60 g.

[0084] (2) Feeding system

[0085] This embodiment (E1) uses the soft apple snail bait of the present invention combined with commercially available macrophage broodstock formulated feed (38% crude protein, 7% crude fat). The total daily feeding amount for the broodstock population is set at 3% of the total live body weight, of which animal feed accounts for 40% and conventional macrophage broodstock formulated feed accounts for 60%. The animal feed portion consists of 80% soft apple snail bait of the present invention and 20% a small amount of fresh small fish.

[0086] Feeding times are set 1 hour before sunset (first meal) and 2 hours after sunset (second meal), with a feeding ratio of 6:4. Soft bait and formulated feed are placed separately into fixed feeding trays for each meal. Check the remaining feed after 2-3 hours. Generally, the remaining feed should be controlled within 10%, and the feeding amount for the next day should be adjusted slightly according to the situation.

[0087] Monitor water temperature, pH, and dissolved oxygen weekly, and ammonia nitrogen and nitrite nitrogen every 3 days. When ammonia nitrogen > 0.5 mg / L or nitrite nitrogen > 0.15 mg / L, reduce animal feed by 10-20% and increase water exchange by 30%.

[0088] (3) Cultivation cycle and indicator records

[0089] The breeding cycle was set at 60 days. Every 20 days, random samples were taken to measure the body weight and gonadal development of the broodstock shrimp (20 female shrimp were sampled and their gonadal mass was measured to calculate the GSI), and the proportion of berried female shrimp and the hatching rate were recorded. At the end of the experiment, the average concentration of total ammonia nitrogen in the pond water was measured.

[0090] This embodiment serves as the main sample group for subsequent comparative experiments.

[0091] IV. Example 2: Adjustment of EM addition ratio and plant-based raw material combination

[0092] Example 2 (E2) has the same overall process flow as Example 1, with only some key parameters adjusted to illustrate that similar technical effects can still be achieved by changing parameters within a limited range.

[0093] Temporary holding and emptying time: The temporary holding time for golden apple snails will be adjusted to 48 hours, while other conditions remain unchanged.

[0094] EM bacterial solution addition and soaking time: The volume ratio of EM bacterial solution to water is 1:900, the soaking time is 4 hours, and the water temperature is about 25℃.

[0095] Adjustment of snail meat mince ratio: Snail meat mince is used as the base, and the plant-based raw materials adopt a combination of carrot: pumpkin: spinach = 1:1:1. The total amount of plant-based raw materials is snail meat mince: plant raw materials: vitamin mineral premix = 5.0: 1.5: 0.3 on a wet basis, which is in the range of (3~6):(0.5~2):(0.1~0.5).

[0096] Hydrophilic gel binder: Only sodium alginate solution (8% solids) is used, at a rate of 1.5% of the total mass of the mixture; a small amount of corn starch paste (6% solids) of about 0.5% is added, and the overall solid content of the gel binder is about 2.0%.

[0097] Probiotic preparations and compound enzyme preparations: No compound enzymes are added, only 0.3% lactic acid bacteria preparation is added.

[0098] Tests showed that the E2 soft block bait contained approximately 39.5% crude protein (dry basis) and 7.2% crude fat, with a residual rate of approximately 92% in water after 2 hours and approximately 82% after 4 hours.

[0099] Under the same pond conditions, replacing the soft block bait in E1 with E2 soft block bait, while maintaining the same total feeding amount and animal feed ratio, and continuously cultivating for 60 days, the measured indicators such as the gonad index and egg-carrying rate of the broodstock shrimp showed slight differences but were generally close to those of E1. This indicates that similar technical effects can still be obtained by adjusting the amount of EM added, the combination of plant materials, and the type of gel binder.

[0100] V. Example 3: Probiotic and Compound Enzyme-Fortified Soft Block Bait

[0101] Example 3 (E3) enhanced the addition of probiotics and compound enzymes based on Example 1 to verify the synergistic effect on further improving digestibility and water quality.

[0102] 1. Differences in soft block bait formulations

[0103] Based on the formulation of Example 1, the amount of probiotic preparation added was increased to 0.4% of the total mass of the mixture (the mass ratio of lactic acid bacteria to Bacillus is 1:1), and the amount of compound enzyme preparation added was 0.4% (the mass ratio of protease:amylase:cellulase is 2:1:1).

[0104] 2. Feeding and comparison design

[0105] Two shrimp ponds with the same conditions as E1 were selected. One pond was fed E1 soft feed (E1 group), and the other was fed E3 soft feed (E3 group), with the same total feeding regime. By measuring the crude protein content in feces and the amount of uneaten feed at the bottom of the pond, it was found that the average crude protein content in the feces of the E3 group was about 8% lower than that of the E1 group, and the weight of uneaten feed at the bottom of the pond was reduced by about 15%, indicating improved digestibility and reduced residual organic matter. At the same time, the average concentration of total ammonia nitrogen in the water of the E3 group was about 10% lower than that of the E1 group.

[0106] VI. Comparative Example 1: No temporary evacuation or EM purification was performed; only simple cleaning was conducted.

[0107] Comparative Example 1 (C1) is used to illustrate that when the multi-stage treatment of "temporary holding and emptying, circulating micro-flow rinsing, and EM purification" of the present invention is ignored, there are safety and water quality risks associated with using golden apple snails as raw materials.

[0108] After the golden apple snails were collected, they were only rinsed in tap water for 10 minutes. They were not temporarily kept for 48-72 hours to drain the water, nor were they soaked in circulating micro-flow water or EM.

[0109] The crushing and seasoning process is the same as in Example 1. Snail meat paste is directly prepared into soft bait, and the formula components are the same as in E1.

[0110] C1 soft bait was used for feeding in the same conditions as E1 broodstock ponds, with the same feeding regime and total amount.

[0111] The results showed that during the 60-day rearing period, the average ammonia nitrogen concentration in the C1 group increased by about 30%, and the peak nitrite nitrogen concentration was significantly higher than that in the E1 group. Some ponds showed mild algal blooms and blackening of the bottom sediment on days 30-40, and more sticky feces and fine particles were visible around the soft feed. The health status of the broodstock shrimp declined slightly, and the mortality rate was about 3 percentage points higher than that of the E1 group.

[0112] This comparative example illustrates that if the multi-stage synergistic purification process of the present invention is omitted, the endogenous pollutants and surface microbial load of the golden apple snail as raw material cannot be effectively controlled, which will have an adverse effect on water quality and the health of the broodstock.

[0113] VII. Comparative Example 2: No hydrophilic gel binder added, directly minced meat and vegetable chunks

[0114] Comparative Example 2 (C2) is used to illustrate the role of hydrophilic gel binders in improving the stability of soft bait in water and reducing the organic load in water bodies.

[0115] The processing of the golden apple snail raw materials is the same as in Example 1 (including temporary holding, rinsing and EM purification).

[0116] In S3, only the snail meat paste is mixed with carrots, pumpkin, pumpkin leaves and vitamin premix at a ratio of snail meat paste: plant raw materials: vitamin premix = 4.5: 1.2: 0.2. No gelatin, sodium alginate or starch paste is added. The mixture is formed by relying solely on the viscosity of the materials themselves. The forming size is the same as that in E1.

[0117] Water stability tests showed that the residual rate was about 70% after 2 hours, and dropped to about 50% after 4 hours, with a large amount of fine debris deposited at the bottom of the tank.

[0118] When C2 feed was used in the same shrimp rearing pond under the same conditions, after a 60-day trial, although the growth and gonadal development of the shrimp basically met the minimum production requirements, the water transparency of the pond decreased significantly. During regular sewage discharge, a lot of soft mud-like sediments could be observed at the bottom. The average concentration of ammonia nitrogen was about 25% higher than that of the E1 group, and the nitrite nitrogen fluctuated greatly.

[0119] This comparative example shows that, although the feeding needs can be temporarily met without the use of hydrophilic gel binders, the dispersion speed of the bait in the water is significantly accelerated, and the decomposition of uneaten bait increases the burden on the bottom sediment and water body, which is not conducive to the long-term stability of the aquatic environment.

[0120] 8. Comparative Example 3: Feeding with traditional ribbonfish meat + formulated feed

[0121] Comparative Example 3 (C3) is used to compare with existing common production modes to demonstrate the comprehensive advantages of the present invention in terms of gonadal development and material costs.

[0122] In shrimp ponds with identical conditions, a traditional feeding method was used, consisting of a combination of cooked and chopped ribbonfish meat and formulated feed for giant freshwater prawns. The total daily feed amount was 3% of the total live weight of the shrimp, with ribbonfish meat accounting for approximately 80% of the animal feed and formulated feed making up the remainder.

[0123] After boiling the ribbonfish meat in boiling water for 5 minutes, cut it into small pieces of about 1cm and put it directly into the pool.

[0124] The results of 60 days of cultivation showed that, compared with the E1 group, the C3 group had an average lower gonad index of about 12%, a lower egg-carrying rate of 8 percentage points, and a lower hatching rate of about 6 percentage points. At the same time, the ribbonfish meat dissolved faster in the water, the average concentration of ammonia nitrogen in the pond water was about 35% higher than that of the E1 group, and obvious flocculent fish meat fragments could be seen near the feeding area 2 hours after feeding.

[0125] From a cost perspective, based on local market prices, the cost of ribbonfish meat is about 2.5 to 3 times that of golden apple snails (calculated at the purchase price); under the same protein supply level, the cost of animal protein in group C3 is significantly higher than that in group E1.

[0126] IX. Summary of Experimental Results

[0127] The table below compares the key indicators of Examples 1-3 and Comparative Examples 1-3 at the end of 60 days of cultivation:

[0128]

[0129] As can be seen from the table:

[0130] 1. Under similar feeding amounts and cost conditions, the gonad index, egg-carrying rate, and hatching rate of groups E1 and E3 in Examples were significantly higher than those of groups C1, C2, and C3, indicating that the present invention significantly improved the reproductive performance of giant freshwater prawn broodstock through a comprehensive scheme of "purification + nutritional enhancement + soft block molding + precise feeding".

[0131] 2. Compared with E1, the average concentration of total ammonia nitrogen in water body C1 (unpurified) was significantly higher, indicating that multi-stage purification treatment plays an important role in reducing the pollutant load inside and outside the snail and maintaining the stability of the water body;

[0132] 3. The residual rate of C2 (non-gel) soft block feed was significantly low after 4 hours, which increased the burden on water quality. In contrast, E1, E2, and E3 use hydrophilic gel binders to control the slow release of soft blocks within 2 to 4 hours, which is beneficial for the gradual feeding of broodstock shrimp and reduces bottom pollution.

[0133] 4. C3 adopts the traditional method of using ribbonfish meat. Although it can meet the supply of animal protein, the gonad development index and egg-carrying rate are lower than those of the E1 group. Moreover, the cost per unit of animal protein is about 2.5 to 3 times that of the proposed method, and the water quality index is also significantly worse.

[0134] Therefore, this invention achieves rapid gonadal development and improved reproductive performance in giant freshwater prawn broodstock while simultaneously controlling raw material costs and ensuring water quality stability, demonstrating significant comprehensive technical benefits.

[0135] 10. Explanation of the generalizability of the implementation method

[0136] The above embodiments are merely illustrative examples and do not constitute a limitation on the scope of protection of this invention. Those skilled in the art can make equivalent substitutions or minor adjustments in the following aspects:

[0137] 1. The temporary holding time of golden apple snails, the flow rate of circulating micro-flow water, the formula and addition ratio of EM bacterial solution can be adjusted within a limited range to adapt to different water temperatures, water quality and golden apple snail pollution load levels in different regions;

[0138] 2. Plant-based raw materials can be replaced or supplemented with other raw materials rich in vitamins and carotenoids, such as pumpkin leaves, spinach, and seaweed, depending on local resource conditions, as long as they meet the specified mass ratio range, they are all within the protection scope of this invention;

[0139] 3. In addition to gelatin, sodium alginate, and starch paste, other food-grade or feed-grade hydrophilic colloids can also be introduced into the hydrophilic gel binder. As long as the soft block can achieve water stability that does not easily disintegrate within 2 to 4 hours, it constitutes an equivalent improvement of the present invention.

[0140] 4. The combination of strains and types of enzymes in probiotic preparations and compound enzyme preparations can be appropriately adjusted according to actual needs. For example, bifidobacteria, xylanase, etc. can be replaced or added, as long as their mechanism of action is still to improve the digestibility and utilization of soft bait and reduce the impact of residual bait on water quality.

[0141] All modifications and improvements made without departing from the spirit and essence of this invention shall fall within the protection scope of this invention.

Claims

1. A method for breeding giant freshwater prawns based on the resource utilization of golden apple snails, characterized in that, Includes the following steps: S1. Place the captured live golden apple snails in clean water for 48-72 hours without feeding them any food, and maintain dissolved oxygen ≥5mg / L to encourage the snails to fully empty their intestinal contents and reduce the load of endogenous pollutants; then use circulating micro-flow water for physical rinsing, followed by soaking in EM bacterial solution to complete biological purification. S2. The purified golden apple snails are put into a crushing device for crushing and then screened through a screen to obtain snail meat paste. Salt and organic acids are added at 1-3% of the weight of the golden apple snail meat. S3. Mix snail meat paste with vitamin-rich plant-based raw materials and vitamin and mineral premix in a mass ratio of (3-6):(0.5-2):(0.1-0.5), and further add a hydrophilic gel binder at 0.5-2.0% of the total mass of the mixture. Then, extrude or mold it into soft apple snail bait with a smooth surface that does not easily disintegrate in water for 2-4 hours. S4. In the rearing pond of giant freshwater prawns, the golden apple snail soft bait is used in combination with the conventional giant freshwater prawn broodstock feed, so that the animal feed accounts for 20-60% of the total daily feed for the broodstock, of which the golden apple snail soft bait accounts for 60-90% of the animal feed mass, and is fed evenly in the evening and at night.

2. The method according to claim 1, characterized in that, In step S1, the golden apple snails are rinsed with circulating micro-flow water at a pressure of 0.2–0.4 MPa and a flow rate of 5–10 L / min for 30–60 min; after rinsing, EM bacterial solution with an effective live bacteria count ≥1×10⁻⁶ is added at a volume ratio of 1:500–1:1000 to the treated water. 8 Soak CFU / mL EM bacterial solution at 25-30℃ for 2-4 hours.

3. The method according to claim 1, characterized in that, The EM bacterial solution is a complex probiotic system composed of lactic acid bacteria, yeast, and photosynthetic bacteria. During preparation, the above-mentioned bacteria are first mixed in a mass ratio of 1:1:1, and then activated with 3-5% brown sugar water for 18-36 hours. After activation, the effective viable bacteria count is not less than 1×10⁻⁶. 8 The concentration of CFU / mL is then added to purified water at a volume ratio of 1:500-1:1000 for soaking treatment.

4. The method according to claim 1, characterized in that, In step S2, the crushing device is a spiral or hammer crusher, and the material temperature is kept ≤40℃ during the crushing process; the screen mesh size is 0.5~2.0mm; the organic acid is selected from citric acid, lactic acid, acetic acid or any combination thereof; the amount of salt added is 1.0~2.0% of the weight of the golden apple snail meat; and the amount of organic acid added is 0.1~0.5% of the weight of the golden apple snail meat.

5. The method according to claim 1, characterized in that, In step S3, the hydrophilic gel binder is selected from gelatin, sodium alginate, starch paste, or a combination thereof; the plant-based raw materials include one or more of carrots, pumpkins, pumpkin leaves, spinach, and laver; the vitamin and mineral premix contains 10,000–30,000 IU / kg of vitamin A, 100–300 mg / kg of vitamin E, 0.6–1.2% of total phosphorus, and 1.0–2.0% of total calcium; the resulting golden apple snail soft bait has a crude protein content of 35–45% and a crude fat content of 6–10%.

6. The method according to claim 1, characterized in that, S3 further includes adding a probiotic preparation and a compound enzyme preparation to the mixture at 0.05 to 0.5% of the total mass of the mixture. The probiotic preparation includes lactic acid bacteria, Bacillus, or a combination thereof, and the compound enzyme preparation includes multiple of protease, amylase, and cellulase.

7. The method according to claim 1, characterized in that, During the feeding process described in S4, the water quality parameters of the broodstock rearing pond are monitored, and the feeding and water exchange are adjusted according to the water quality. The dissolved oxygen is maintained above 5 mg / L, the ammonia nitrogen concentration is controlled below 0.5 mg / L, and the nitrite nitrogen concentration is controlled below 0.15 mg / L. When any indicator exceeds the limit, the amount of animal feed is reduced by 10-30%, and the water exchange ratio is increased by 10-30%.

8. The method according to claim 1, characterized in that, In S4, the feeding times are set to any 2 to 3 time periods, including 1 hour before sunset, 1 to 2 hours after sunset, and 1 hour before dawn. The amount of each feeding is 1 to 3% of the total body weight of the broodstock shrimp during that time period.

9. The method according to claim 1, characterized in that, Using the weight growth rate, gonad index, egg-carrying rate, and hatching rate of giant freshwater prawns before and after implementing the method as evaluation indicators, compared with the control group fed with ribbonfish meat or ordinary snail meat under the same total feeding conditions, the gonad index of the golden apple snail soft bait group increased by 10-30%, the egg-carrying rate increased by 5-20%, and the average concentration of total ammonia nitrogen in the culture water decreased by 20-40%.

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