A method for artificial breeding and breeding of wild snails

Abstract

The present application relates to the field of aquaculture technology, and discloses a wild snail artificial breeding method, which is used for artificial domestication of wild parent snails captured in the sea area and large-scale seed production, and comprises the following steps: collecting wild parent snails, determining oxidation stress indexes of the wild parent snails, and judging whether there is oxidative damage; placing the parent snails with oxidative damage in a repair pond, and feeding bait to repair and domesticate; mating and spawning the parent snails without oxidative damage to obtain planktonic larvae, and cultivating the planktonic larvae to metamorphic stage; inducing the larvae at the metamorphic stage, and dynamically feeding carriers according to the development progress of the larvae to make the larvae attach and metamorphose into juvenile snails; feeding the juvenile snails after metamorphosis with functional opening material, and cultivating the juvenile snails into young snails. The present application realizes objective diagnosis and accurate repair of wild parent damage, chemical signal induction of larval metamorphosis, and stable cultivation of juvenile snail opening period, and has the characteristics of high survival rate, good stability and simple operation.

Description

Technical Field

[0001] This invention relates to the field of aquaculture technology, and in particular to a method for the artificial breeding and propagation of wild sea snails. Background Technology

[0002] Sea snails are an important species for marine aquaculture in my country. Currently, there is considerable research on the artificial breeding of species such as the mud snail, the red-veined snail, and the tubular snail. Existing techniques generally employ a process of "collecting wild parent stock—intensive cultivation—spawning and hatching—planktonic larvae cultivation—metamorphosis and attachment—juvenile snail cultivation."

[0003] However, existing technologies still face the following technical bottlenecks in industrial applications: First, the latent damage to wild broodstock is difficult to repair. Current technologies mainly focus on the appearance screening of broodstock snails and the enhancement of conventional feed. However, wild snails are mostly caught by trawls, and their hepatopancreatic tissue generally suffers from oxidative damage. Furthermore, they experience stress responses due to sudden environmental changes after being introduced into ponds. Current technologies lack objective diagnostic methods for the extent of damage to broodstock snails, making targeted repair impossible. This results in high mortality rates and asynchronous gonadal development in broodstock snails after introduction into ponds.

[0004] Second, there is a lack of precise control methods for inducing larval metamorphosis. Existing technologies mainly induce larval metamorphosis by laying physical attachment substrates such as sand and netting, but they have not recognized the key inducing role of chemical signals generated by specific microbial films in larval metamorphosis, resulting in large fluctuations and poor stability in the metamorphosis rate.

[0005] Third, juvenile snails rely on live food for their initial feeding, or food that easily spoils the water quality. Current technology mainly feeds juvenile snails live larvae or minced clam meat during their transition to a new diet. Feeding live larvae is technically challenging, while feeding minced clam meat easily spoils the water quality, leading to mass mortality of juvenile snails.

[0006] Therefore, this invention proposes a method for the artificial breeding and propagation of wild sea snails. Summary of the Invention

[0007] The purpose of this invention is to solve the problems of difficult repair of damage to wild parent stock, difficulty in inducing metamorphosis of larvae, and difficulty in survival of juvenile snails when they open in the prior art, and to propose an artificial breeding method for wild sea snails.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: a method for artificial breeding and propagation of wild sea snails, used for the artificial domestication and large-scale seed production of wild parent snails captured in sea areas, comprising the following steps: Step S1: Collect wild parent snails and measure oxidative stress indicators in their hepatopancreatic tissue. Based on the comparison of oxidative stress indicators with preset thresholds, determine whether oxidative damage exists. Step S2: Place the parent snails with oxidative damage in a remediation tank with an absorbent substrate, and feed them with feed soaked in compound plant extracts for remediation and acclimatization until the oxidative stress indicators return to normal. Step S3: Mating and laying eggs on parent snails that have no oxidative damage, collecting egg sacs to hatch into planktonic larvae, and cultivating the planktonic larvae to the metamorphosis stage; Step S4: For larvae that have entered the metamorphosis stage, a microbial vector containing Flavobacterium and Rhodobacterium is used for induction, and the vector is dynamically released according to the larval development progress to allow them to attach and metamorphose into juvenile snails. Step S5 involves feeding the metamorphosed juvenile snails with functional starter feed that reduces their metabolic burden, thus cultivating them to juvenile snail size.

[0009] The beneficial effects of the technical solution provided by this invention include at least the following: This invention collects wild parent snails and measures oxidative stress indicators in their hepatopancreatic tissue. By comparing these oxidative stress indicators with preset thresholds, it determines whether oxidative damage exists, enabling an objective diagnosis of the degree of damage to parent snails. This upgrades traditional experience-based enhanced cultivation to a precise diagnostic repair model.

[0010] This invention involves placing parent snails with oxidative damage in a remediation pond with an absorbent substrate and feeding them bait soaked in compound plant extracts to remediate and acclimate them until their oxidative stress indicators return to normal. This method can specifically repair the hepatopancreatic oxidative damage of wild parent snails, significantly reduce the mortality rate upon entering the pond, and achieve synchronous gonadal maturation and stable spawning.

[0011] This invention involves mating and laying eggs with parent snails that have not suffered from oxidative damage, collecting egg sacs for hatching to obtain planktonic larvae, and then cultivating the planktonic larvae to the metamorphosis stage. This provides a sufficient and uniform source of larvae for subsequent metamorphosis induction, ensuring the continuity of the seedling production process.

[0012] This invention induces metamorphosis in larvae by using a bacterial vector containing Flavobacterium and Rhodobacterium, and dynamically releases the vector according to the larval development progress. It can precisely induce larval attachment and metamorphosis by utilizing the chemical signals generated by specific bacterial groups, upgrading traditional physical induction to biochemical signal induction, and significantly improving the stability of metamorphosis rate and batch-to-batch consistency.

[0013] This invention uses a functional starter feed that reduces the metabolic burden on metamorphosed juvenile snails, allowing them to grow to the size of young snails. This solves the technical problems of reliance on traditional live feed and the easy spoilage of water by shellfish meat, enabling juvenile snails to survive stably and grow rapidly during the starter period. Attached Figure Description

[0014] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the method flow provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the process flow provided for an embodiment of the present invention. Detailed Implementation

[0016] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a method for artificial breeding and propagation of wild sea snails according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0018] The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0019] The specific scheme of the artificial breeding and propagation method for wild sea snails provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0020] Please see Figure 1 and Figure 2 The diagram illustrates a method flow chart and a process flow chart of an artificial breeding and propagation method for wild sea snails according to an embodiment of the present invention. This method is used for the artificial domestication and large-scale seed production of wild parent snails captured in sea areas, and includes the following steps: Step S1: Collect wild parent snails and measure oxidative stress indicators in their hepatopancreatic tissue. Based on the comparison of oxidative stress indicators with preset thresholds, determine whether oxidative damage exists. Step S2: Place the parent snails with oxidative damage in a remediation tank with an absorbent substrate, and feed them with feed soaked in compound plant extracts for remediation and acclimatization until the oxidative stress indicators return to normal. Step S3: Mating and laying eggs on parent snails that have no oxidative damage, collecting egg sacs to hatch into planktonic larvae, and cultivating the planktonic larvae to the metamorphosis stage; Step S4: For larvae that have entered the metamorphosis stage, a microbial vector containing Flavobacterium and Rhodobacterium is used for induction, and the vector is dynamically released according to the larval development progress to allow them to attach and metamorphose into juvenile snails. Step S5 involves feeding the metamorphosed juvenile snails with functional starter feed that reduces their metabolic burden, thus cultivating them to juvenile snail size.

[0021] It should be noted that wild parent snails refer to adult snails obtained from natural sea areas through legal fishing methods, with intact shells, normal vitality, and no obvious mechanical damage. They are the basic seed source for artificial breeding.

[0022] Oxidative stress indicators are biochemical indicators that can reflect the degree of oxidative damage to the hepatopancreatic tissue of parent snails. These include malondialdehyde content and superoxide dismutase activity. By detecting these indicators, it is possible to accurately determine whether parent snails have latent oxidative damage.

[0023] The preset thresholds refer to the critical values ​​of oxidative stress indicators determined based on a large number of wild conch sample detection data. Among them, the malondialdehyde threshold is 5.0 nmol / mgprot and the superoxide dismutase threshold is 120 U / mgprot, which are used as standard limits for judging oxidative damage.

[0024] Oxidative damage refers to the imbalance between the oxidative and antioxidant systems in parent snails in the wild due to environmental stress, food scarcity, and other factors. This leads to the accumulation of reactive oxygen species and causes latent damage to the hepatopancreatic tissue, which affects the reproductive performance of parent snails.

[0025] Adsorbent substrate refers to a pool bottom paving material made by mixing zeolite powder and fine sand in a mass ratio of 3:7 after seawater activation treatment. It has a porous structure and strong adsorption capacity, which can adsorb harmful substances in the water and improve the water quality environment of the remediation pool.

[0026] Compound plant extracts refer to a combination of natural active substances made by mixing Eucommia ulmoides leaf extract, Ginkgo biloba leaf extract and curcumin in a mass ratio of 5:3:2. They have antioxidant, anti-inflammatory and tissue repair effects.

[0027] Restoration and acclimatization refers to the process by which parent snails suffering from oxidative damage gradually recover their physiological functions and adapt to the artificial breeding environment in a specially designed restoration pond through suitable environmental conditions and feeding with functional feed.

[0028] An egg sac is a gelatinous sac-like structure containing a large number of fertilized eggs, produced after mating between parent snails. Its morphology varies slightly depending on the species of snail and it serves as a natural carrier for embryonic development.

[0029] Planktonic larvae refer to the larval stage that hatches from the egg sac and has the ability to plank. At this stage, the larvae rely on planktonic algae for food and need to go through a certain period of growth and development before entering the metamorphosis stage.

[0030] Metamorphosis refers to the critical developmental period in which planktonic larvae, after reaching a certain stage of growth, undergo fundamental changes in morphology, structure, and lifestyle, and are about to transition from a planktonic to a terrestrial life.

[0031] Microbial carriers are porous biological carriers with a composite microbial community of Flavobacterium and Rhodobacterium on their surface. The carrier material is modified zeolite with a pore size of 50 to 100 μm, which can provide a suitable microbial environment and physical attachment surface for larval attachment and metamorphosis.

[0032] Flavobacterium refers to a group of Gram-negative bacteria selected from the sediment of the natural habitat of sea snails, which have the activity of promoting larval attachment and metamorphosis. Their metabolites can induce the expression of genes related to larval metamorphosis.

[0033] Rhodobulb refers to a group of marine bacteria that work synergistically with Flavobacterium to inhibit the growth of harmful bacteria such as Vibrio and can secrete larval metamorphosis-inducing factors.

[0034] Dynamic release refers to the operation method of releasing microbial carriers into the cultivation pond in batches and in different areas according to the larval development progress and the sensitive period of metamorphosis. This can ensure that larvae at different developmental stages can obtain suitable metamorphosis induction conditions.

[0035] Juvenile snails refer to the larval stage after completing attachment metamorphosis and possessing the ability to live on the bottom. Their morphology has initially acquired the characteristics of adult snails, but they are small in size and their physiological functions are not yet fully mature.

[0036] Functional starter feed refers to a special feed made with small molecule peptides as the main nitrogen source, combined with kelp polysaccharides, yeast culture and phospholipids. It has the functions of easy digestion and absorption, reducing metabolic burden and enhancing immunity.

[0037] Metabolic burden refers to the digestive and metabolic stress experienced by juvenile snails after ingesting unsuitable food because their digestive systems are not yet fully developed. This manifests as reduced digestive enzyme activity and slow growth.

[0038] Juvenile snail specifications refer to the standard that juvenile snails reach a shell height of 1.0 to 1.5 cm and a weight of 0.5 to 1.0 g after a period of cultivation, with stable physiological functions and adapted to the artificial breeding environment. At this time, they can be transferred to the adult snail breeding stage.

[0039] In one specific implementation, this method is applied to the large-scale artificial seedling cultivation of *Rhododendron simsii* in the northern coastal region, and the specific implementation details are as follows: The Bohai Bay area of ​​the Shandong Peninsula was selected as the collection site for parent snails. Wild red snails with shell height of 8 to 12 cm and vigorous activity were collected by trapping them before the parent snail breeding season in May and June each year. During transportation, the water temperature was maintained at 18 to 20 degrees Celsius and the salinity at 28 to 30‰, and violent shaking was avoided.

[0040] Immediately after collection, the parent snails were transported to the seedling workshop. Ten snails were randomly sampled in each batch, and hepatopancreatic tissue was obtained through dissection. The tissue was cleaved and centrifuged at 8000 rpm for 15 minutes at 4°C. The supernatant was collected, and the malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were determined using a commercially available kit. The results were compared with preset thresholds. A batch of parent snails was considered to have oxidative damage if the MDA content was higher than 5.0 nmol / mgprot or the SOD activity was lower than 120 U / mgprot.

[0041] Prepare a cement remediation tank with dimensions of 10m × 5m × 1.2m. Mix zeolite powder that has undergone 24-hour seawater activation treatment with fine sand at a mass ratio of 3:7 and lay the mixture at the bottom of the tank to a thickness of 8 to 10 cm as an absorbent substrate. Place parent snails with oxidative damage into the remediation tank at a density of 15 snails / square meter. Control the water temperature at 20 to 22 degrees Celsius, salinity at 29 to 31‰, dissolved oxygen ≥ 6 mg / L, and pH at 7.8 to 8.2, and change 30% of the water daily.

[0042] To prepare a compound plant extract infusion, Eucommia ulmoides leaf extract, Ginkgo biloba leaf extract, and curcumin were mixed in a mass ratio of 5:3:2 and added to seawater to prepare an infusion solution with a concentration of 0.5 g / L. After stirring in the dark for 30 minutes, the solution was allowed to settle, and the supernatant was collected for later use. Fresh, live four-cornered clams were selected as the base feed. The clams were crushed and soaked in the infusion solution with aeration for 2 hours. After soaking, they were rinsed three times with clean seawater to remove any residual extracts from the surface and fed to the clams within 30 minutes. Feed three times a day, with an initial feeding amount of 5% to 8% of the parent snail's body weight. Test oxidative stress indicators every three days. When the malondialdehyde content decreases by less than 10% or the superoxide dismutase activity increases by less than 15%, increase the feeding amount to 8% to 10%. When the malondialdehyde content is below 4.0 nmol / mgprot or the superoxide dismutase activity is above 150 U / mgprot, reduce the feeding amount to 3% to 5%. Continue the repair and acclimatization process for 20 to 30 days until the oxidative stress indicators return to normal.

[0043] Parent snails without oxidative damage were placed in a spawning pond measuring 15m × 8m × 1.5m at a female-to-male ratio of 1:1.5. PVC pipes were laid in the pond as attachment points for egg sacs. The water temperature was controlled at 24-26 degrees Celsius and the salinity at 30-32‰. Live oysters and Manila clams were fed daily at a rate of 10-15% of the parent snails' body weight, and a slight water flow was maintained in the pond. After mating and spawning, the attachment of egg sacs was observed daily. Within 24 hours of spawning, egg sacs attached to the pond walls and PVC pipes were collected and placed in perforated polypropylene hatching baskets with holes of 2-3mm in diameter to prevent egg sacs from falling off while ensuring water circulation.

[0044] Placing an incubation basket in a circulating water incubation system, controlling the incubation water temperature to 25 to 27°C and salinity to 30‰, adding 10 mg / L povidone-iodine to circulating water as a safe disinfectant, controlling the water flow rate at 0.5 m / s, and performing continuous scouring and aerated incubation on the surfaces of oocysts. Starting from the 5th day of incubation, applying periodic temperature difference stimulation 3 times a day, with each stimulation lasting for 30 minutes, controlling the temperature difference at 2 to 3°C, which is achieved by raising the temperature to 28°C and then lowering it to 25°C. Continuous stimulation is performed for 3 to 5 days to promote synchronous hatching of larvae by breaking the oocysts.

[0045] Collecting synchronously hatched planktonic larvae, placing them in a larval rearing pond at a density of 0.1 to 0.3 individuals / mL, controlling the water temperature to 23 to 25°C and salinity to 29 to 31‰, feeding with a mixed algae solution of *Isochrysis galbana*, *Chaetoceros* and *Chlorella*, with an initial feeding density of 50,000 to 80,000 cells / mL, feeding 4 times a day, and gradually increasing the density to 100,000 to 150,000 cells / mL as the larvae grow, and culturing for 15 to 20 days until the larvae enter the metamorphosis stage.

[0046] Preparing a flora carrier: collecting a sediment sample from the conch habitat in the Bohai Bay, separating the native microbial community by density gradient centrifugation, inoculating the community into immunomagnetic beads containing specific antibodies against *Flavobacterium* and *Rhodobacter* to capture the target flora, then inoculating the target flora into a screening medium with cellulose as the sole carbon source and nitrate as the sole nitrogen source for directional domestication culture. In a biofilm reactor, subjecting the modified zeolite carrier to oscillation adsorption culture with the domesticated target flora for 48 hours to form an initial biofilm, then culturing with circulating seawater, and regularly detecting the flora structure on the carrier surface. When the sum of the relative abundances of *Flavobacterium* and *Rhodobacter* is higher than 50% and the relative abundance of *Vibrio* is lower than 5%, the carrier is determined to be qualified.

[0047] Collecting water samples from the larval rearing pond every day, detecting the concentration of arachidonic acid in the water body by high performance liquid chromatography. When the concentration reaches 0.8 μg / L for the first time, it is determined that the larval population enters the sensitive metamorphosis period, and the first batch of qualified carriers are uniformly put into the rearing pond at a density of 50 per cubic meter; continue monitoring the arachidonic acid concentration, when the concentration reaches the peak and then drops to 0.3 μg / L, put the second batch of qualified carriers into the edge area of the rearing pond at a density of 30 per cubic meter; when it is detected that the number of juvenile conchs attached to the surface of a single carrier reaches 50 to 80 individuals per carrier, remove the carrier from the rearing pond.

[0048] Functional starter feed was prepared using blue clams and sand eels as raw materials. These were mixed in a 1:1 mass ratio, crushed, and then subjected to enzymatic hydrolysis with a complex protease at 50°C, pH 7.0, and for 6 hours. After hydrolysis, peptide powder with a molecular weight less than 1000 Da was collected by filtration and used as a nitrogen source. The peptide powder was then compounded with kelp polysaccharides, yeast culture, and phospholipids in a mass ratio of 70:10:15:5. After thorough mixing, granular starter feed with a particle size of 100 to 200 μm was prepared. After metamorphosis, the juvenile snails are placed in a juvenile snail rearing pond at a density of 1,000 to 1,500 snails per square meter. The water temperature is controlled at 22 to 24 degrees Celsius and the salinity at 28 to 30‰. Functional starter feed is provided three times a day, with the initial feeding amount being 5% to 8% of the juvenile snails' body weight. The amount is adjusted according to the feeding situation. The snails are reared for 30 to 40 days until their shell height reaches 1.0 to 1.5 cm and their weight reaches 0.5 to 1.0 g, reaching the size of juvenile snails. At this point, they can be transferred to adult snail farming or stock enhancement.

[0049] Step S1 further includes the following sub-steps: Step S1-1: After collecting wild parent snails, random samples are taken in batches, and the hepatopancreas tissue of the sampled individuals is broken and centrifuged to collect the supernatant for testing; Steps S1-2: The malondialdehyde content and superoxide dismutase activity in the supernatant were determined using a kit method as indicators of oxidative stress. Steps S1-3: The measured malondialdehyde content and superoxide dismutase activity are compared with the corresponding preset thresholds. When the malondialdehyde content is higher than the malondialdehyde threshold or the superoxide dismutase activity is lower than the superoxide dismutase threshold, it is determined that the batch of parent snails has oxidative damage.

[0050] It should be noted that random sampling in batches refers to dividing the collected wild parent snails into groups according to transportation batches or collection areas, and randomly selecting a certain number of samples from each group for testing to ensure that the test results are representative and avoid misjudgments caused by individual differences.

[0051] The hepatopancreatic tissue refers to the core metabolic organ in the snail that combines the functions of the liver and pancreas. This tissue is most sensitive to oxidative damage and is a key tissue site for detecting oxidative stress.

[0052] Disruption refers to the process of using a tissue homogenizer to break down liver and pancreatic tissue into a homogenate, thereby releasing intracellular oxidative stress-related substances into the solution for subsequent detection.

[0053] Centrifugation refers to placing a homogenized fragment of liver and pancreas tissue into a centrifuge, where the centrifugal force generated by high-speed rotation separates the solid and liquid components, thus separating tissue fragments and cellular debris.

[0054] The supernatant is the clear liquid that remains at the top of the centrifuge tube after centrifugation. It contains malondialdehyde, superoxide dismutase, and other target substances released from hepatopancreatic cells.

[0055] The reagent kit method refers to the use of commercially available biochemical detection kits and the detection process according to a pre-set operating procedure and reaction system. It features standardized operation and accurate and stable results.

[0056] Malondialdehyde (MDA) content refers to the amount of MDA produced per unit mass of liver and pancreas tissue. MDA is the final product of lipid peroxidation, and its content directly reflects the severity of tissue oxidative damage.

[0057] Superoxide dismutase activity refers to the ability of superoxide dismutase to catalyze the decomposition of superoxide anions per unit mass of liver and pancreatic tissue. This enzyme is an important antioxidant enzyme in the body, and a decrease in its activity indicates a decline in antioxidant capacity.

[0058] The malondialdehyde (MDA) threshold is a critical value for MDA content determined based on a large amount of data from the detection of liver and pancreas tissues from healthy wild conch. It serves as the boundary between the normal state and the state of oxidative damage.

[0059] The superoxide dismutase threshold refers to the critical value of superoxide dismutase activity determined based on the detection data of healthy wild snail samples. A value below this threshold indicates abnormal function of the parent snail's antioxidant system.

[0060] In one specific implementation, this detection process is applied to the screening of artificial breeding stock for *Rhododendron simsii* in the Yellow Sea. The specific implementation details are as follows: Every year in early May, wild *Rhododendron simsii* snails with shells 8 to 12 cm in height, intact shells, and vigorous activity are collected from the northern Yellow Sea using traps. They are divided into 10 batches of 50 snails each. Ten parent snails are randomly selected from each batch as test samples. The hepatopancreas tissue is rapidly dissected and separated. 2g of hepatopancreas tissue from each parent snail is placed in a sterile grinding tube, and 8mL of pre-cooled physiological saline is added. The mixture is then ground for 3 minutes at 4 degrees Celsius using a high-speed tissue homogenizer to prepare a homogenate.

[0061] Transfer the homogenate into centrifuge tubes and place them in a refrigerated centrifuge. Set the centrifugation temperature to 4 degrees Celsius, the speed to 8000 rpm, and the centrifugation time to 15 minutes. After centrifugation, use a sterile pipette to aspirate the clear supernatant from the top and transfer it into a new sterile centrifuge tube. Place the tube in an ice box for testing to prevent degradation of the target substance.

[0062] Malondialdehyde (MDA) and superoxide dismutase (SOD) assay kits were used, and the reaction systems were prepared according to the kit instructions. 50 μL of supernatant was added to each well of a 96-well plate, followed by the corresponding reagents from the kits. After mixing by vortexing, the 96-well plates were incubated at 37°C for 30 minutes. After incubation, the absorbance of the MDA reaction solution was measured at 532 nm and the absorbance of the SOD reaction solution was measured at 550 nm using a microplate reader. The MDA content and SOD activity of each sample were calculated based on the standard curves provided by the kits.

[0063] The malondialdehyde (MDA) threshold was set at 5.0 nmol / mgprot, and the superoxide dismutase (SOD) threshold was set at 120 U / mgprot. The test results of 10 samples from each batch were averaged. If the average MDA content of a batch was higher than 5.0 nmol / mgprot, or the average SOD activity was lower than 120 U / mgprot, the batch of parent snails was considered to have oxidative damage and needed to proceed to the subsequent remediation and acclimatization stage. If both indicators were within the threshold range, the batch of parent snails was considered to have no oxidative damage and could be directly transferred to the mating and egg-laying stage.

[0064] Step S2 further includes the following sub-steps: Step S2-1: Zeolite powder is activated by seawater and then mixed with fine sand. This mixture is laid at the bottom of the remediation tank as an adsorbent substrate. Parent snails with oxidative damage are then placed into the remediation tank. Step S2-2: Mix Eucommia ulmoides leaf extract, Ginkgo biloba leaf extract and curcumin, add to seawater, stir in the dark and let stand, and take the filtrate as the complex plant extract soaking solution after solid-liquid separation. Steps S2-3: Place the bait in the soaking solution and aerate it. After removing it, rinse it with clean water to remove any surface residue. Feed the bait within 30 minutes. Steps S2-4: Feed the snails multiple times a day, with the amount being 5% to 8% of their body weight. Regularly measure oxidative stress indicators and adjust the feeding amount according to the trend of indicator changes until the indicators return to normal.

[0065] Furthermore, in sub-steps S2-4, the steps of periodically measuring oxidative stress indicators and adjusting the feeding amount according to the trend of indicator changes until the indicators return to normal include: Oxidative stress indicators were measured periodically, and the rate of change of malondialdehyde content and superoxide dismutase activity compared with the previous measurement was calculated. When the rate of decrease in malondialdehyde content is less than the preset first rate threshold, or the rate of increase in superoxide dismutase activity is less than the preset second rate threshold, the feeding amount will be increased to 8% to 10% of the parent snail's body weight. When the malondialdehyde content is lower than the first preset multiple of the malondialdehyde threshold, or the superoxide dismutase activity is higher than the second preset multiple of the superoxide dismutase threshold, the feeding amount should be reduced to 3% to 5% of the parent snail's body weight. Repeat the above steps until the malondialdehyde content is below the malondialdehyde threshold and the superoxide dismutase activity is above the superoxide dismutase threshold.

[0066] It should be noted that seawater activation treatment refers to soaking zeolite powder in natural seawater and letting it stand at room temperature for 24 hours, so that the zeolite powder can fully adsorb seawater minerals and microorganisms, activate its porous adsorption properties, and improve the adsorption efficiency of harmful substances in the water.

[0067] Eucommia ulmoides leaf extract refers to a substance extracted from Eucommia ulmoides leaves that is rich in active ingredients such as chlorogenic acid and Eucommia ulmoides polysaccharides. It has antioxidant, anti-inflammatory and tissue repair effects.

[0068] Ginkgo biloba extract refers to substances extracted from ginkgo leaves that contain active ingredients such as flavonoids and terpene lactones. These substances can enhance the body's antioxidant capacity and reduce oxidative stress damage.

[0069] Curcumin is a natural polyphenolic compound extracted from turmeric. It has strong antioxidant and anti-inflammatory activities and can inhibit the accumulation of oxidation products.

[0070] Compound plant extract soaking solution refers to a functional soaking solution made by mixing Eucommia ulmoides leaf extract, Ginkgo biloba leaf extract and curcumin in a certain proportion and dissolving them in seawater. It is used to impart restorative activity to bait.

[0071] Stirring in the dark refers to stirring the mixture under light-proof conditions to prevent light from damaging the heat-sensitive active ingredients in the plant extracts and to ensure their stable efficacy.

[0072] Solid-liquid separation refers to the process of separating solid impurities and supernatant from a mixed system through natural sedimentation or filtration to obtain a pure soaking solution.

[0073] Aeration soaking refers to introducing air into the bait during the soaking process, so that the soaking liquid can evenly contact the surface of the bait and penetrate into the interior, thereby enhancing the adsorption effect of active ingredients.

[0074] Regular testing refers to detecting oxidative stress indicators of parent snails at fixed time intervals to track the recovery progress and provide data support for adjusting the feeding amount.

[0075] The rate of change refers to the proportion of the difference between the current oxidative stress index and the previous measurement result to the previous measurement value, and is used to quantify the trend of index change.

[0076] The first rate threshold refers to the preset minimum rate of decrease in malondialdehyde content; a value below this indicates slow repair progress.

[0077] The second rate threshold refers to the preset minimum rate of increase of superoxide dismutase activity; a value below this indicates insufficient recovery of antioxidant capacity.

[0078] The first preset multiple refers to a specific ratio coefficient below the malondialdehyde threshold, used to determine whether the repair effect is close to meeting the standard.

[0079] The second preset multiple refers to a specific proportional coefficient that is higher than the superoxide dismutase threshold, used to determine whether antioxidant capacity has been excessively restored.

[0080] In one specific implementation, this restoration and domestication process is applied to the artificial breeding of *Rhododendron simsii* in the Bohai Bay, and the specific implementation details are as follows: Prepare a cement remediation tank with dimensions of 10m × 5m × 1.2m. Select zeolite powder with a particle size of 0.5 to 1mm and add three times its volume of natural seawater. Let it stand at room temperature for 24 hours for activation treatment. Mix the activated zeolite powder with fine sand at a mass ratio of 3:7 and spread it at the bottom of the remediation tank to a thickness of 10cm. Then, pour seawater into the tank to a depth of 80cm, controlling the water temperature at 20 to 22 degrees Celsius, salinity at 29 to 31‰, dissolved oxygen ≥6mg / L, and pH at 7.8 to 8.2. Place the red whelks, which were determined to have oxidative damage in step S1, into the remediation tank at a density of 15 whelks / square meter. After acclimatization for 24 hours, feeding can begin.

[0081] To prepare a compound plant extract soaking solution, Eucommia ulmoides leaf extract, Ginkgo biloba leaf extract, and curcumin were weighed at a mass ratio of 5:3:2 and added to seawater to form a mixture with a concentration of 0.5 g / L. The mixture was stirred for 30 minutes under dark conditions, allowed to settle for 1 hour, and then filtered to obtain the supernatant, which was the soaking solution. Fresh, live four-cornered clams were selected as the base feed, crushed, and placed in the soaking solution. Air was aerated and the clams were soaked for 2 hours. After soaking, they were rinsed three times with clean seawater to remove any residual soaking solution from the surface. Feeding was completed within 30 minutes.

[0082] Feed three times daily, with an initial feed amount calculated as 5% to 8% of the parent snail's body weight. Every three days constitutes a testing cycle; three parent snails are randomly selected to determine the malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in their hepatopancreatic tissue. The rate of decrease in MDA content and the rate of increase in SOD activity are calculated, with a first rate threshold of 10%, a second rate threshold of 15%, a first preset multiple of 0.8, and a second preset multiple of 1.2.

[0083] When the malondialdehyde (MDA) content decreases by less than 10%, or the superoxide dismutase (SOD) activity increases by less than 15%, adjust the next feeding amount to 8% to 10% of the parent snail's body weight. When the MDA content is less than 0.8 times that of 5.0 nmol / mgprot (i.e., 4.0 nmol / mgprot), or the SOD activity is more than 1.2 times that of 120 U / mgprot (i.e., 144 U / mgprot), adjust the feeding amount to 3% to 5% of the parent snail's body weight. Repeat the above detection and adjustment steps for 20 to 30 days until the MDA content of the parent snails is stably below 5.0 nmol / mgprot and the SOD activity is stably above 120 U / mgprot, thus completing the repair and acclimatization process.

[0084] Step S3 further includes the following sub-steps: Step S3-1: Place parent snails without oxidative damage into a spawning pond lined with egg sac attachment devices for mating and spawning; Step S3-2: Collect the egg sacs attached to the pool wall or attaching device and put them into a perforated hatching basket; Step S3-3: Place the hatching basket in the circulating water hatching system, and use circulating water with added safe disinfectant to rinse the surface of the egg sacs for aeration and hatching under the conditions of hatching water temperature and hatching salinity. Steps S3-4: When the embryos in the egg sac develop to the veil larva stage, the egg sac is subjected to multiple periodic temperature difference stimuli every day to cause the larvae to hatch synchronously. Steps S3-5: Collect the synchronously hatched planktonic larvae, cultivate them at the larval rearing density, feed them planktonic larval stage food, and cultivate them until the metamorphosis stage.

[0085] It should be noted that the egg sac attachor is a special device placed in the spawning pond for the parent snails to attach their egg sacs when laying eggs. It is made of non-toxic PVC and is tubular or plate-shaped with a rough surface treatment to enhance the adhesion of the egg sacs.

[0086] Spawning ponds are cement or fiberglass ponds specifically designed for parent snails to mate and lay eggs. They are equipped with temperature control, salinity control, and micro-flow water functions to provide a suitable reproductive environment for the parent snails.

[0087] A perforated hatching basket is a mesh container used to hold egg sacs. The perforation diameter is 2 to 3 mm, which ensures water flow and prevents egg sacs from falling off, making centralized hatching management easier.

[0088] A circulating water incubation system is an incubation device consisting of a water pump, pipes, a filter, and a temperature control device. It can continuously provide clean, temperature-stable circulating water to ensure a uniform incubation environment for egg sacs.

[0089] Hatching water temperature refers to the water temperature controlled during the hatching of egg sacs, which is set as a constant temperature range suitable for embryonic development according to the species of snail.

[0090] Hatching salinity refers to the salinity of the water body controlled during the hatching of egg sacs to maintain stability and avoid damage to the embryos caused by changes in osmotic pressure.

[0091] Safe disinfectants are disinfectants that have no toxic side effects on conch embryos. They are used to inhibit the growth of harmful microorganisms on the surface of the egg sac and ensure the normal development of the embryo.

[0092] Circulating water flushing refers to the process of continuously circulating water over the surface of the egg sac to remove impurities and metabolic waste, while simultaneously replenishing dissolved oxygen to provide sufficient oxygen for embryonic development.

[0093] Aeration incubation refers to introducing air into the water body during the incubation process to maintain a high dissolved oxygen level and promote water circulation, thus preventing localized oxygen deficiency.

[0094] Periodic temperature difference stimulation refers to the use of alternating heating and cooling to create temperature fluctuations, which stimulates larvae in the egg sac to complete embryonic development and hatch synchronously, thereby increasing the hatching synchronization rate.

[0095] Synchronous hatching refers to the process by which larvae in the same batch of egg sacs break through the gelatinous membrane of the egg sac and hatch within a similar time frame under temperature difference stimulation, which facilitates subsequent centralized cultivation.

[0096] Planktonic larval food refers to microorganisms suitable for planktonic larvae to feed on, mainly unicellular algae such as golden algae, chamomile, and chlorella, which are rich in nutrients and easily digested and absorbed by larvae.

[0097] Larval rearing density refers to the number of planktonic larvae released per unit volume of water. It is set according to the larval size and metabolic intensity to avoid excessive density leading to oxygen deficiency or intensified competition.

[0098] In one specific implementation, this process is applied to the large-scale artificial seedling cultivation of *Rhododendron simsii* in the Yellow Sea, and the specific implementation details are as follows: Prepare a spawning pond with dimensions of 15m × 8m × 1.5m. Evenly lay PVC tubular egg sac attachers in the pond at 50cm intervals, and place a 10cm thick layer of fine sand at the bottom. Place *Rhododendron simsii* snails (without oxidative damage) into the spawning pond at a female-to-male ratio of 1:1.5. Control the water temperature at 24-26°C, salinity at 30-32‰, dissolved oxygen ≥6mg / L, and pH at 7.8-8.2. Feed the snails daily with live oyster meat and Manila clams at 10-15% of their body weight. Maintain a slight water flow in the pond at a velocity of 0.3m / s to simulate the natural marine water flow environment and promote mating and spawning.

[0099] Within 24 hours after the parent snails lay their eggs, gently scrape the egg sacs attached to the pond wall and attaching apparatus with a soft scraper to avoid damaging the gelatinous membrane of the egg sacs. Put the collected egg sacs into perforated PVC hatching baskets, with each basket not exceeding 60% of its volume to prevent the egg sacs from being squeezed.

[0100] The hatching baskets are suspended in the hatching tank of the circulating water hatching system. The water temperature in the hatching tank is controlled at 25 to 27 degrees Celsius, and the salinity is controlled at 30‰. 10 mg / L povidone-iodine is added to the circulating water as a safe disinfectant. The circulating water pump is started to maintain a water flow rate of 0.5 m / s to continuously flush the surface of the egg sacs. At the same time, the aeration device is turned on to aerate the water through air stones, maintaining the dissolved oxygen in the water at 7 to 8 mg / L to ensure oxygen supply for embryonic development.

[0101] On day 12 of incubation (the total incubation period for *Rhodotorula pulveratum* ovipositors is 18 days, during which they develop into vegetative larvae), periodic temperature fluctuation stimulation is applied. Stimulation is performed three times a day, with each stimulation lasting 30 minutes. The specific procedure is as follows: first, the water temperature in the incubation tank is raised to 28 degrees Celsius and maintained for 15 minutes, then rapidly cooled to 25 degrees Celsius and maintained for 15 minutes. This temperature fluctuation stimulates the embryos to develop and mature synchronously.

[0102] On the 18th day of incubation, the larvae begin to hatch. After more than 80% of the larvae have hatched, the planktonic larvae are collected using a 200-mesh sieve and released into the larval rearing tank at a density of 0.1 to 0.3 cells / mL. The water temperature in the rearing tank is controlled at 23 to 25 degrees Celsius, and the salinity at 29 to 31‰. A mixed algal solution of golden algae, chaete algae, and chlorella is fed daily, with an initial feeding density of 50,000 to 80,000 cells / mL, divided into four feedings per day. As the larvae grow, the feeding density is gradually increased to 100,000 to 150,000 cells / mL. During the rearing period, 30% of the water is changed daily to maintain water quality. After 15 to 20 days of rearing, the larvae develop to a shell height of 1000 to 1500 μm, develop eyespots and legs, and enter the metamorphosis stage.

[0103] Step S4 further includes the following sub-steps: Step S4-1: In an independent biofilm reactor, the target bacterial population, which has been domesticated by specific screening media of Flavobacterium and Rhodobacterium, is used to perform oscillatory adsorption culture on a porous carrier to form an initial biofilm of the target bacterial population on the surface of the carrier. Step S4-2: Biofilm on a porous carrier is cultured using circulating seawater. During the culture period, the microbial community structure on the carrier surface is detected regularly, and the carbon source type and nitrogen source concentration are dynamically adjusted according to the detection results to selectively promote the growth of Flavobacterium and Rhodobacterium. Step S4-3: When the sum of the relative abundance of Flavobacterium and Rhodobacterium is higher than any other genera, and the relative abundance of Vibrio is lower than the preset abundance threshold, stop the culture and determine that the vector is qualified. Step S4-4: Determine the release time based on the development progress of the planktonic larvae, release qualified carriers into the larval rearing pond in batches, and remove the carriers after the larvae have attached to the expected proportion, thus completing the metamorphosis induction.

[0104] Further, in sub-step S4-1, the target bacterial population acclimated to specific selection media of Flavobacterium and Rhodobacterium is obtained through the following steps: Substrate samples were collected from natural marine snail habitats, and native microbial communities were obtained by density gradient centrifugation. The isolated microbial communities were inoculated into immunomagnetic beads containing specific antibodies against Flavobacterium and Rhodobacterium to capture the target bacterial population. The target bacterial population was inoculated into a biofilm reactor and acclimated in a selective medium with cellulose as the sole carbon source and nitrate as the sole nitrogen source to obtain the target bacterial population acclimated by the specific selective medium.

[0105] Furthermore, in sub-step S4-2, the steps of periodically detecting the bacterial community structure on the carrier surface and dynamically adjusting the carbon source type and nitrogen source concentration based on the detection results include: Biofilm samples were collected from the surface of the vector regularly, and genomic DNA was extracted for real-time quantitative PCR detection to quantify the gene copy number of Flavobacterium, Rhodobacterium, and Vibrio. The sum of abundance of Flavobacterium and Rhodobacterium, as well as abundance of Vibrio, were calculated based on the test results. When the sum of the abundance of Flavobacterium and Rhodobacterium is lower than a first preset threshold, cellulose is added to the culture medium and glucose is reduced, so that the percentage increase in the mass concentration of cellulose in the culture medium after addition is greater than the percentage decrease in the mass concentration of glucose in the culture medium after addition. When the abundance of Vibrio spp. is higher than the second preset threshold, nitrate is added to the culture medium and peptone is reduced, so that the percentage increase in the mass concentration of nitrate in the culture medium after addition is greater than the percentage decrease in the mass concentration of peptone in the culture medium after addition.

[0106] Furthermore, in sub-step S4-4, the step of determining the release timing based on the developmental progress of the planktonic larvae includes: Water samples were collected daily from the larval rearing pond to detect the concentration of chemical signaling substances specifically secreted by the larvae before metamorphosis. When the concentration first reaches the activation threshold, the larval population is determined to have entered the sensitive period of metamorphosis, and the first batch of qualified carriers are put into the cultivation pool. Continue to monitor the concentration change. When the concentration reaches its peak and begins to drop to the fall threshold, it is determined that the first batch of larvae has completed attachment. Then, the second batch of qualified carriers is introduced into different areas of the cultivation pool. When the number of juvenile snails attached to the carrier surface reaches the expected value, the carrier is removed from the cultivation tank.

[0107] It should be noted that a biofilm reactor is a specialized device used to cultivate microbial biofilms. It has functions such as temperature control, oxygen control, and oscillation mixing, and can provide a stable environment for the attachment and growth of microbial communities.

[0108] Specific selection media are media specifically designed for the selective culture of Flavobacterium and Rhodobacterium species. They inhibit the growth of other bacteria through a specific combination of carbon and nitrogen sources.

[0109] Porous carriers are porous materials used to support microbial communities. They are made of modified zeolite with a pore size of 50 to 100 μm, have a large specific surface area and strong adsorption capacity, and provide physical support for biofilm formation.

[0110] Oscillating adsorption culture refers to a culture method in which the target bacterial community is brought into full contact with the surface of a porous carrier and adsorbed and colonized under oscillating conditions, so as to quickly form an initial biofilm.

[0111] The initial biofilm refers to the thin film-like bacterial community structure formed by the initial colonization of the target bacterial community on the surface of a porous carrier, which is the basis for subsequent bacterial community proliferation and functional stability.

[0112] Circulating seawater culture refers to using filtered natural seawater as a culture medium, which provides a continuous supply of nutrients to the biofilm and a channel for the removal of metabolic waste through circulation.

[0113] Microbial community structure refers to the composition and relative proportion of various microorganisms in the biofilm on the surface of the carrier, which directly affects the metamorphosis induction effect and the ability to control diseases.

[0114] Dynamic regulation of carbon source types refers to adjusting the proportion of different carbon sources in the culture medium based on the results of bacterial community structure detection, so as to selectively promote the growth of target bacterial communities.

[0115] Dynamic regulation of nitrogen source concentration refers to adjusting the concentration of different nitrogen sources in the culture medium based on the results of bacterial community structure detection, in order to inhibit the proliferation of harmful bacteria and promote the metabolism of target bacterial communities.

[0116] Relative abundance refers to the proportion of gene copy number of a certain bacterial genus to the total number of gene copy number of all detected bacterial gene genera, and is used to quantify the composition of bacterial community structure.

[0117] The preset abundance threshold refers to the preset maximum allowable relative abundance of Vibrio spp.; a value below this threshold indicates that harmful bacteria in the biofilm are effectively controlled.

[0118] A qualified carrier is a porous carrier in which Flavobacterium and Rhodobacterium are dominant in the surface biofilm, Vibrio is below a preset threshold, and it has the functions of inducing metamorphosis and biosafety.

[0119] Developmental progress refers to the degree to which planktonic larvae advance towards the metamorphosis stage in terms of morphology, structure, and physiological function, and is judged by a combination of chemical signaling substance concentration and morphological characteristics.

[0120] The timing of release refers to the point in time when the microbial carrier is introduced based on the developmental progress of the larvae, so as to ensure that the carrier exerts the best metamorphosis induction effect.

[0121] Chemical signaling substances refer to small organic molecules that are specifically secreted by planktonic larvae before they enter the metamorphosis stage. Changes in their concentration can reflect the metamorphosis preparation state of the larval population.

[0122] The trigger threshold is the minimum concentration of a chemical signaling substance that triggers the larval population to enter the sensitive period of metamorphosis.

[0123] The metamorphosis sensitive period refers to the developmental stage in which the larval physiological state is most susceptible to external induction signals and the success rate of metamorphosis is highest.

[0124] The drop-off threshold refers to the critical value at which the concentration of chemical signaling substances decreases after reaching its peak. A value below this threshold indicates that the metamorphosis and attachment process of the first batch of larvae is basically complete.

[0125] The expected ratio refers to the proportion of the number of larvae that are expected to successfully attach to the carrier surface out of the total number of larvae, and is used to determine the degree of completion of metamorphosis induction.

[0126] In one specific implementation, this process is applied to the large-scale artificial seedling cultivation of *Rhododendron simsii* in the Bohai Bay. The specific implementation details are as follows: Sediment samples were collected from the natural habitat of *Rhodotorula buergerianum* in the Bohai Bay, and the native microbial community was isolated using density gradient centrifugation. The isolated microbial community was inoculated into immunomagnetic beads containing specific antibodies against *Flavobacterium* and *Rhodotorula*, and incubated at 4°C for 1 hour to capture the target bacterial population. The target bacterial population was then inoculated into a biofilm reactor and directionally acclimatized for 7 days at 25°C and dissolved oxygen levels of 5–6 mg / L using a selection medium with cellulose as the sole carbon source and nitrate as the sole nitrogen source, to obtain the specifically screened target bacterial population.

[0127] Select modified zeolite porous carriers with a particle size of 3 to 5 mm, place them in a biofilm reactor, add the acclimated bacterial solution of the target flora, and perform oscillation adsorption culture for 48 hours at 25 °C and 120 r / min, so that an initial biofilm is formed on the surface of the carriers. Then switch to circulating seawater for culture, with a seawater salinity of 30‰ and a temperature of 25 °C, and replace 30% of the circulating seawater every day. Collect biofilm samples from the carrier surface every 2 days, extract genomic DNA, and use real-time fluorescence quantitative PCR technology to detect the gene copy numbers of *Flavobacterium*, *Rhodobacter* and *Vibrio*. Set the first preset threshold to 50%, the second preset threshold to 5%, and the preset abundance threshold to 3%.

[0128] When the sum of the relative abundances of *Flavobacterium* and *Rhodobacter* is detected to be lower than 50%, add cellulose to the medium to increase the concentration from 1 g / L to 1.5 g / L, and simultaneously reduce the glucose concentration from 0.8 g / L to 0.3 g / L. The 50% increase percentage of cellulose is greater than the 62.5% decrease percentage of glucose; when the relative abundance of *Vibrio* is detected to be higher than 5%, add nitrate to the medium to increase the concentration from 0.5 g / L to 1.0 g / L, and simultaneously reduce the peptone concentration from 0.6 g / L to 0.2 g / L. The 100% increase percentage of nitrate is greater than the 66.7% decrease percentage of peptone. Continue culturing until the sum of the relative abundances of *Flavobacterium* and *Rhodobacter* is higher than that of any other bacterial genus, and the relative abundance of *Vibrio* is lower than 3%, the carrier is judged to be qualified, and the culture is stopped for later use.

[0129] In the *Rapana venosa* planktonic larva culture pond (specification: 10 m×5 m×1.2 m), collect water samples at 9 a.m. every day, and use high-performance liquid chromatography to detect the concentration of the chemical signal substance arachidonic acid in the water body. Set the start threshold to 0.8 μg / L, the drop-back threshold to 0.3 μg / L, and the expected ratio to 70%. When the concentration of arachidonic acid is detected to reach 0.8 μg / L for the first time, uniformly put the first batch of qualified carriers into the culture pond at a density of 50 pieces per cubic meter; continue to monitor the concentration change, when the concentration drops to 0.3 μg / L after reaching a peak of about 2.5 μg / L, put the second batch of qualified carriers into the edge area of the culture pond at a density of 30 pieces per cubic meter. Observe the attachment condition on the carrier surface every day, when the number of attached juvenile snails reaches 70% of the total number of larvae, remove the carriers from the culture pond with a net to complete the metamorphosis induction. At this time, the shell height of the juvenile snails is about 1200 μm, and they already have the ability to live benthically.

[0130] Wherein in step S5, the following sub-steps are further included: Step S5-1, using *Aloidis laevis* or *Ammodytes personatus* as raw materials, perform enzymolysis treatment with compound protease to obtain peptide powder with a molecular weight of less than 1000 Da that can be directly absorbed by juvenile snails as a nitrogen source; Step S5-2: The peptide powder is compounded with kelp polysaccharide, yeast culture and phospholipids to obtain a metabolically regulated starter feed with synergistic effects of immune regulation, intestinal protection and absorption promotion; Step S5-3: The prepared metabolically regulated starter feed is used as the sole food for the juvenile snails to grow them to the size of young snails.

[0131] It should be noted that complex protease hydrolysis refers to a biocatalytic process in which multiple proteases work synergistically on the raw protein to break down large protein molecules into small peptides, thereby improving the efficiency of protein digestion and absorption.

[0132] Peptide powder refers to a mixture of small molecule peptides in powder form obtained through enzymatic hydrolysis and subsequent processing. The molecular weight is less than 1000 Da, which can be directly absorbed by the intestines of juvenile snails without additional digestion and decomposition.

[0133] Nitrogen source refers to the nutrient that provides nitrogen for the growth and development of juvenile snails. It is the core raw material for the formation of biological macromolecules such as proteins and nucleic acids in the body. In this invention, small molecule peptide powder is used as the core nitrogen source.

[0134] Kelp polysaccharides are water-soluble polysaccharides extracted from kelp, which have physiological functions such as enhancing the body's immunity and regulating the balance of intestinal microecology.

[0135] Yeast culture refers to a mixture obtained by fermenting yeast, which contains yeast cells, metabolites and fermentation substrates, and can supplement the vitamins, minerals and prebiotics needed by juvenile snails.

[0136] Phospholipids are lipids containing phosphate groups. They are important components of the cell membranes of juvenile snails and can also promote the absorption of fat-soluble nutrients and protect the intestinal mucosa.

[0137] Compound formulation refers to mixing and blending multiple nutritional ingredients in a specific ratio to allow each component to work synergistically and enhance the overall nutritional efficacy and physiological activity of the feed.

[0138] Metabolic regulation starter feed refers to special starter feed designed for the metabolic characteristics and physiological needs of juvenile snails. It can regulate the metabolic level of juvenile snails, reduce the metabolic burden, and at the same time take into account nutritional supply and physiological regulation functions.

[0139] Immunomodulation refers to the ability of active ingredients in feed to regulate the immune function of juvenile snails and enhance their resistance to environmental stress and pathogens.

[0140] Intestinal protection refers to the ability of active ingredients in feed to protect the integrity of the intestinal mucosa of juvenile snails and maintain the normal physiological structure and digestive and absorptive functions of the intestine.

[0141] Synergistic absorption refers to the interaction of various components in the feed, which work together to promote the absorption and utilization of nutrients by juvenile snails in many ways, such as improving digestive efficiency, protecting absorption organs, and regulating the absorption environment.

[0142] The single feed refers to feeding only this metabolically regulating starter feed during the juvenile snail rearing stage, without supplementing it with other feeds, to ensure the stability of nutrient supply and the continuity of the regulatory effect.

[0143] In one specific implementation, this process is applied to the large-scale artificial seedling cultivation of *Rhododendron simsii* in the Bohai Bay. The specific implementation details are as follows: Fresh blue clams and sand eels were selected as raw materials, mixed in a 1:1 mass ratio, and rinsed thoroughly with clean water. The raw materials were then crushed into a paste-like consistency with a particle size of less than 5mm using a crusher. The paste was transferred to an enzymatic hydrolysis reactor, and purified water was added at a material-to-liquid ratio of 1:3. The pH of the reaction system was adjusted to 7.0, and the temperature was set to 50 degrees Celsius. 2% (by mass) of a complex protease, composed of neutral protease, trypsin, and papain in a 2:1:1 mass ratio, was added to the reactor. After thorough mixing, the mixture was enzymatically hydrolyzed at a constant temperature of 50 degrees Celsius for 6 hours. During the hydrolysis process, continuous low-speed stirring was maintained to ensure sufficient contact between the enzyme and the substrate.

[0144] After enzymatic hydrolysis, the reaction system was heated to 95 degrees Celsius and held at that temperature for 15 minutes to inactivate the enzyme. The residue was then removed by filtration using a plate and frame filter press to obtain the enzymatic hydrolysate. The hydrolysate was then transferred to a vacuum concentration tank and concentrated to a solid content of 30% under a vacuum of 0.08 MPa and a temperature of 60 degrees Celsius. It was then dried using a spray dryer with an inlet air temperature of 180 degrees Celsius and an outlet air temperature of 80 degrees Celsius to obtain peptide powder with a molecular weight less than 1000 Da, which was then sealed and stored for later use.

[0145] The prepared peptide powder, kelp polysaccharide, yeast culture, and phospholipids were weighed according to a mass ratio of 70:10:15:5. All raw materials were fed into a high-speed mixer and mixed for 20 minutes at 1500 r / min to ensure uniform mixing. The mixed material was then fed into a granulator and wet granulation was used to prepare granular feed with a particle size of 100 to 200 μm. The feed was then dried in a hot air dryer at 45 degrees Celsius until the moisture content was below 8%, yielding a metabolically regulated starter feed, which was then sealed and stored away from light.

[0146] Juvenile *Rhododendron simsii* that have undergone metamorphosis induction are placed in a rearing pond at a density of 1000 to 1500 snails per square meter. The rearing pond measures 10m × 5m × 1.2m. The water temperature is controlled at 22 to 24 degrees Celsius, salinity at 28 to 30‰, dissolved oxygen at ≥6 mg / L, and pH at 7.8 to 8.2. 30% of the water is changed daily to maintain water quality. The prepared metabolically regulated starter feed is used as the sole food source, fed three times a day at 8:00 AM, 12:00 PM, and 6:00 PM. The initial feed amount is 5% to 8% of the juvenile snail's body weight, and is gradually adjusted according to the snail's feeding behavior and growth rate. When feeding, the feed is evenly scattered into the rearing pond, and slight aeration is activated simultaneously to ensure that the feed is evenly suspended in the water, facilitating feeding by the juvenile snails.

[0147] During the rearing period, observe the growth and feeding status of the juvenile snails daily, and promptly clean up uneaten food and feces from the bottom of the pond to avoid water pollution. Continue rearing for 30 to 40 days until the juvenile snails reach a shell height of 1.0 to 1.5 cm and a weight of 0.5 to 1.0 g, with stable physiological functions and strong activity, reaching the standard size of juvenile *Rhizoctonia solani*. At this time, the juvenile snails can be transferred to adult snail rearing ponds for further cultivation or used for marine aquaculture.

[0148] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for artificially breeding and propagating wild sea snails, used for the artificial domestication and large-scale seed production of wild parent snails captured in sea areas, characterized in that, Includes the following steps: Step S1: Collect wild parent snails and measure oxidative stress indicators in their hepatopancreatic tissue. Based on the comparison of oxidative stress indicators with preset thresholds, determine whether oxidative damage exists. Step S2: Place the parent snails with oxidative damage in a remediation tank with an absorbent substrate, and feed them with feed soaked in compound plant extracts for remediation and acclimatization until the oxidative stress indicators return to normal. Step S3: Mating and laying eggs on parent snails that have no oxidative damage, collecting egg sacs to hatch into planktonic larvae, and cultivating the planktonic larvae to the metamorphosis stage; Step S4: For larvae that have entered the metamorphosis stage, a microbial vector containing Flavobacterium and Rhodobacterium is used for induction, and the vector is dynamically released according to the larval development progress to allow them to attach and metamorphose into juvenile snails. Step S5 involves feeding the metamorphosed juvenile snails with functional starter feed that reduces their metabolic burden, thus cultivating them to juvenile snail size.

2. The method for artificial breeding and propagation of wild sea snails according to claim 1, characterized in that: Step S1 further includes the following sub-steps: Step S1-1: After collecting wild parent snails, random samples are taken in batches, and the hepatopancreas tissue of the sampled individuals is broken and centrifuged to collect the supernatant for testing; Steps S1-2: The malondialdehyde content and superoxide dismutase activity in the supernatant were determined using a kit method as indicators of oxidative stress. Steps S1-3: The measured malondialdehyde content and superoxide dismutase activity are compared with the corresponding preset thresholds. When the malondialdehyde content is higher than the malondialdehyde threshold or the superoxide dismutase activity is lower than the superoxide dismutase threshold, it is determined that the batch of parent snails has oxidative damage.

3. The method for artificial breeding and propagation of wild sea snails according to claim 1, characterized in that: Step S2 further includes the following sub-steps: Step S2-1: Zeolite powder is activated by seawater and then mixed with fine sand. This mixture is laid at the bottom of the remediation tank as an adsorbent substrate. Parent snails with oxidative damage are then placed into the remediation tank. Step S2-2: Mix Eucommia ulmoides leaf extract, Ginkgo biloba leaf extract and curcumin, add to seawater, stir in the dark and let stand, and take the filtrate as the complex plant extract soaking solution after solid-liquid separation. Steps S2-3: Place the bait in the soaking solution and aerate it. After removing it, rinse it with clean water to remove any surface residue. Feed the bait within 30 minutes. Steps S2-4: Feed the snails multiple times a day, with the amount being 5% to 8% of their body weight. Regularly measure oxidative stress indicators and adjust the feeding amount according to the trend of indicator changes until the indicators return to normal.

4. The method for artificial breeding and propagation of wild sea snails according to claim 3, characterized in that, In sub-steps S2-4, the step of periodically measuring oxidative stress indicators and adjusting the feeding amount according to the trend of indicator changes until the indicators return to normal includes: Oxidative stress indicators were measured periodically, and the rate of change of malondialdehyde content and superoxide dismutase activity compared with the previous measurement was calculated. When the rate of decrease in malondialdehyde content is less than the preset first rate threshold, or the rate of increase in superoxide dismutase activity is less than the preset second rate threshold, the feeding amount will be increased to 8% to 10% of the parent snail's body weight. When the malondialdehyde content is lower than the first preset multiple of the malondialdehyde threshold, or the superoxide dismutase activity is higher than the second preset multiple of the superoxide dismutase threshold, the feeding amount should be reduced to 3% to 5% of the parent snail's body weight. Repeat the above steps until the malondialdehyde content is below the malondialdehyde threshold and the superoxide dismutase activity is above the superoxide dismutase threshold.

5. The method for artificial breeding and propagation of wild sea snails according to claim 1, characterized in that: Step S3 further includes the following sub-steps: Step S3-1: Place parent snails without oxidative damage into a spawning pond lined with egg sac attachment devices for mating and spawning; Step S3-2: Collect the egg sacs attached to the pool wall or attaching device and put them into a perforated hatching basket; Step S3-3: Place the hatching basket in the circulating water hatching system, and use circulating water with added safe disinfectant to rinse the surface of the egg sacs for aeration and hatching under the conditions of hatching water temperature and hatching salinity. Steps S3-4: When the embryos in the egg sac develop to the veil larva stage, the egg sac is subjected to multiple periodic temperature difference stimuli every day to cause the larvae to hatch synchronously. Steps S3-5: Collect the synchronously hatched planktonic larvae, cultivate them at the larval rearing density, feed them planktonic larval stage food, and cultivate them until the metamorphosis stage.

6. The method for artificial breeding and propagation of wild sea snails according to claim 1, characterized in that: Step S4 further includes the following sub-steps: Step S4-1: In an independent biofilm reactor, the target bacterial population, which has been domesticated by specific screening media of Flavobacterium and Rhodobacterium, is used to perform oscillatory adsorption culture on a porous carrier to form an initial biofilm of the target bacterial population on the surface of the carrier. Step S4-2: Biofilm on a porous carrier is cultured using circulating seawater. During the culture period, the microbial community structure on the carrier surface is detected regularly, and the carbon source type and nitrogen source concentration are dynamically adjusted according to the detection results to selectively promote the growth of Flavobacterium and Rhodobacterium. Step S4-3: When the sum of the relative abundance of Flavobacterium and Rhodobacterium is higher than any other genera, and the relative abundance of Vibrio is lower than the preset abundance threshold, stop the culture and determine that the vector is qualified. Step S4-4: Determine the release time based on the development progress of the planktonic larvae, release qualified carriers into the larval rearing pond in batches, and remove the carriers after the larvae have attached to the expected proportion, thus completing the metamorphosis induction.

7. The method for artificial breeding and propagation of wild sea snails according to claim 6, characterized in that, In sub-step S4-1, the target bacterial population acclimated to the Flavobacterium and Rhodobacterium specific selection media is obtained through the following steps: Substrate samples were collected from natural marine snail habitats, and native microbial communities were obtained by density gradient centrifugation. The isolated microbial communities were inoculated into immunomagnetic beads containing specific antibodies against Flavobacterium and Rhodobacterium to capture the target bacterial population. The target bacterial population was inoculated into a biofilm reactor and acclimated in a selective medium with cellulose as the sole carbon source and nitrate as the sole nitrogen source to obtain the target bacterial population acclimated by the specific selective medium.

8. The method for artificial breeding and propagation of wild sea snails according to claim 6, characterized in that, In sub-step S4-2, the step of periodically detecting the bacterial community structure on the carrier surface and dynamically adjusting the carbon source type and nitrogen source concentration based on the detection results includes: Biofilm samples were collected from the surface of the vector regularly, and genomic DNA was extracted for real-time quantitative PCR detection to quantify the gene copy number of Flavobacterium, Rhodobacterium, and Vibrio. The sum of abundance of Flavobacterium and Rhodobacterium, as well as abundance of Vibrio, were calculated based on the test results. When the sum of the abundance of Flavobacterium and Rhodobacterium is lower than a first preset threshold, cellulose is added to the culture medium and glucose is reduced, so that the percentage increase in the mass concentration of cellulose in the culture medium after addition is greater than the percentage decrease in the mass concentration of glucose in the culture medium after addition. When the abundance of Vibrio spp. is higher than the second preset threshold, nitrate is added to the culture medium and peptone is reduced, so that the percentage increase in the mass concentration of nitrate in the culture medium after addition is greater than the percentage decrease in the mass concentration of peptone in the culture medium after addition.

9. The method for artificial breeding and propagation of wild sea snails according to claim 6, characterized in that, In sub-step S4-4, the step of determining the release timing based on the developmental progress of the planktonic larvae includes: Water samples were collected daily from the larval rearing pond to detect the concentration of chemical signaling substances specifically secreted by the larvae before metamorphosis. When the concentration first reaches the activation threshold, the larval population is determined to have entered the sensitive period of metamorphosis, and the first batch of qualified carriers are put into the cultivation pool. Continue to monitor the concentration change. When the concentration reaches its peak and begins to drop to the fall threshold, it is determined that the first batch of larvae has completed attachment. Then, the second batch of qualified carriers is introduced into different areas of the cultivation pool. When the number of juvenile snails attached to the carrier surface reaches the expected value, the carrier is removed from the cultivation tank.

10. The method for artificial breeding and propagation of wild sea snails according to claim 1, characterized in that: Step S5 further includes the following sub-steps: Step S5-1: Using blue clam or sand eel as raw material, the mixture is hydrolyzed by compound protease to obtain peptide powder with a molecular weight of less than 1000 Da that can be directly absorbed by juvenile snails as a nitrogen source. Step S5-2: The peptide powder is compounded with kelp polysaccharide, yeast culture and phospholipids to obtain a metabolically regulated starter feed with synergistic effects of immune regulation, intestinal protection and absorption promotion; Step S5-3: The prepared metabolically regulated starter feed is used as the sole food for the juvenile snails to grow them to the size of young snails.

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