A method for improving the stress resistance of fallen seedlings of the Oriental Wind Snail.

Abstract

This invention provides a method for improving the stress resistance of fallen larvae of the Oriental Wind Snail, relating to the field of Oriental Wind Snail farming technology. The farming process is as follows: (1) After cleaning the farming pond and exposing it to the sun, a layer of sieve cloth and sand is laid on the bottom of the pond in sequence, seawater is injected, and compound probiotic liquid is sprinkled; (2) The fallen larvae along with the attached sand are transferred to the farming pond. For the first 15 days after the transfer, they are fed compound feed, and after 15 days, they are fed compound feed and fresh feed; (3) During the farming period, an anti-stress agent is administered every 3 days. This invention guides the fallen larvae of the Oriental Wind Snail to adapt to the farming environment by controlling environmental conditions, reducing the stress impact caused by environmental changes; by using appropriate compound feed and anti-stress agents, the growth and development of the immune organs of the fallen larvae can be effectively promoted, as well as the balance of intestinal flora can be regulated, promoting the digestion and absorption of nutrients, improving metabolic efficiency, enhancing the body's immunity, thereby improving their stress resistance and effectively reducing mortality.

Description

Technical Field

[0001] This invention relates to the field of whelk farming technology, and in particular to a farming method for improving the stress resistance of whelk seedlings that have fallen to the ground. Background Technology

[0002] The East Wind Whelk, also known as the Flower Whelk, Wang Whelk, or Yellow Whelk, is a mollusc belonging to the family Bellacidae in the order Acanthoglossales. Its meat is plump, delicate, and delicious, earning it the reputation of "pearl in the dish." Rich in protein, vitamins, essential amino acids, and trace elements, it is a typical high-protein, low-fat, and high-calcium natural animal-based health food. The East Wind Whelk has become a highly sought-after high-quality marine shellfish in domestic and international markets in recent years. It is now accepted by aquaculture farmers along the southeastern coast of China, and production is gradually reaching a significant scale.

[0003] Fallen snail seedlings refer to juvenile snails that have completed metamorphosis from the vegetal larvae and transitioned from the planktonic stage to the benthic stage. During this stage, due to the incomplete development of the snail's hepatobiliary function, unstable microbial community, change in feeding methods, and changes in the living environment, juvenile snails are very fragile, prone to death, and unlikely to grow into healthy breeding snails.

[0004] Currently, in traditional aquaculture, changes in temperature, salinity, and harmful substances in the aquaculture ponds cause stress reactions in juvenile snails, resulting in decreased feeding, reduced vitality, and simply feeding them algae and formulated feed, which is insufficient to meet their nutritional needs. This can induce endocrine disorders, weaken the immunity of hatchlings, affect their growth, and lead to high mortality rates. Summary of the Invention

[0005] In view of this, the present invention proposes a breeding method to improve the stress resistance of fallen seedlings of the Oriental Wind Snail, thereby promoting the growth of juvenile Oriental Wind Snails and increasing their survival rate.

[0006] The technical solution of this invention is implemented as follows: A method for improving the stress resistance of fallen seedlings of the Oriental Wind Snail includes the following steps: (1) After cleaning the aquaculture pond, expose it to the sun, lay the sieve cloth and sand layer on the bottom of the pond in sequence, pour in seawater, and sprinkle compound probiotic liquid; (2) Transfer the seedlings along with the attached sand to the breeding pond. Feed them with compound feed for the first 15 days after the transfer. After 15 days, feed them with compound feed and fresh bait. The compound feed includes the following ingredients by weight: 30-40 parts fish meal, 12-16 parts corn gluten meal, 2-3 parts Rhizopus spp., 3-5 parts polysaccharide, 0.08-0.12 parts glucuronide, 0.6-1.2 parts compound amino acids, 3-5 parts carboxymethyl cellulose, 5-7 parts sodium alginate, and 3-5 parts gelatin. (3) During the breeding period, administer anti-stress agents once every 3 days.

[0007] Furthermore, the sand layer has a thickness of 2-3 cm; the sand layer is composed of sea sand, ceramsite, and zeolite powder in a mass ratio of 7-9:0.4-0.5:1-2; the compound probiotic liquid is sprayed at a rate of 150-200 mL / m³. 3 During the first 15 days after transfer, the amount of compound feed should be 1~1.5g / m³. 3 Fifteen days after transfer, the amount of compound feed should be 2-3 g / m³. 3 The feeding amount of the chilled bait is 1~1.2g / m³. 3 The dosage of the anti-stress agent is 0.3~0.5 g / m³. 3 .

[0008] Furthermore, after seawater is injected, the water temperature is controlled at 25~28℃, the salinity at 26~32‰, and the dissolved oxygen at ≥6mg / L.

[0009] Furthermore, the raw materials of the compound probiotic liquid include: *Pseudomonas aeruginosa*, *Bacillus subtilis*, *Lactobacillus acidophilus*, glucose, and water, wherein the mass ratio of glucose to water is 1-2:10; and the concentration of *Pseudomonas aeruginosa* is 5 × 10⁻⁶. 5 ~1×10 6 CFU / mL; the concentration of Bacillus subtilis is 1.0~2.0×10⁻⁶ CFU / mL. 9 CFU / mL; the concentration of the Lactobacillus acidophilus was 5.0 × 10⁻⁶. 6 ~2.0×10 7 CFU / mL.

[0010] Furthermore, the compound feed comprises the following raw materials in parts by weight: 30-40 parts fish meal, 12-16 parts corn gluten meal, 2-3 parts Rhizopus cylindrica, 3-5 parts polysaccharide, 0.08-0.12 parts glucuronide, 0.6-1.2 parts compound amino acids, 3-5 parts carboxymethyl cellulose, 5-7 parts sodium alginate, and 3-5 parts gelatin.

[0011] Furthermore, the composite amino acids include threonine, glutamic acid, valine, alanine, and glycine in a mass ratio of 0.1~0.2:1~2:0.5~1:3~5:1~2.

[0012] Furthermore, the polysaccharides include Apocynum venetum polysaccharide, Sorbus nigra polysaccharide, and Fucoidan in a mass ratio of 4~8:4~8:2~4.

[0013] Furthermore, the chilled bait is one or more of squid, miscellaneous fish, shrimp meat, and crab meat.

[0014] Furthermore, the anti-stress agent comprises a complex polysaccharide and a traditional Chinese medicine extract in a mass ratio of 2-4:10-12.

[0015] Furthermore, the complex polysaccharide includes Apocynum venetum polysaccharide, Sorbus nigra polysaccharide and Lycium barbarum polysaccharide in a mass ratio of 6~9:3~4:2~5; the traditional Chinese medicine extract includes Morinda officinalis extract, Gynostemma pentaphyllum extract and Curculigo orchioides extract in a mass ratio of 7~10:3~5:3~5.

[0016] Furthermore, flowing water is used during the breeding period, and the water flow and aeration are turned off when feeding compound feed, chilled bait and anti-stress agents.

[0017] Furthermore, the stocking density of seedlings planted on the ground is 1.6~1.8×10⁻⁶. 4 only / m 2 The standard size of the seedlings is 8±1mm.

[0018] Furthermore, the preparation method of the Apocynum venetum polysaccharide is as follows: take the dried whole Apocynum venetum herb, crush it, pass it through a 60-mesh sieve, add water and soak it for 5-6 hours at a material-to-liquid ratio of 1:15-20 g / mL, then place it in an ultrasonic extractor and extract it for 60-70 minutes at 40-60℃ and 500-600W. Filter it, take the extract and centrifuge it (5000r / min, 10min), take the supernatant, concentrate it, add 4 times the volume of 95-98% v / v ethanol and mix it, place it at 4-6℃ for 10-12 hours, centrifuge it again (5000r / min, 10min), take the precipitate and freeze-dry it to obtain Apocynum venetum polysaccharide.

[0019] Furthermore, the preparation method of the black chokeberry polysaccharide is as follows: the dried black chokeberry fruit is crushed, passed through a 60-mesh sieve, and soaked in water at a material-to-liquid ratio of 1:2~5 g / mL for 5~8 hours. Then, it is placed in an ultrasonic extractor and extracted at 40~60℃ and 300~400W for 60~70 minutes. After filtration, the extract is centrifuged (6000r / min, 10 minutes). The supernatant is concentrated and then mixed with 4 times the volume of 95~98% v / v ethanol. The mixture is placed at 4~6℃ for 10~12 hours and centrifuged again (6000r / min, 10 minutes). The precipitate is freeze-dried to obtain black chokeberry polysaccharide.

[0020] Furthermore, the preparation method of the wolfberry polysaccharide is as follows: take dried wolfberry fruit, crush it through a 60-mesh sieve to obtain powder, reflux extract it with 2 times the volume of petroleum ether for 4-5 hours, take it out and dry it to obtain defatted wolfberry powder, add water to the defatted wolfberry powder at a material-to-liquid ratio of 1:30-40 g / mL and soak it for 1-2 hours, then place it in an ultrasonic extractor and extract it at 40-60℃ and 200-300W for 60-70 minutes, filter it, take the extract and centrifuge it (4000r / min, 10min), take the supernatant, concentrate it, add 4 times the volume of 95-98% v / v ethanol and mix it, place it at 4-6℃ for 10-12 hours, centrifuge it again (46000r / min, 10min), take the precipitate and freeze dry it to obtain wolfberry polysaccharide.

[0021] Furthermore, the preparation method of the Morinda officinalis extract is as follows: the dried Morinda officinalis is pulverized, and the Morinda officinalis powder and 95-98% v / v ethanol are mixed at a material-to-liquid ratio of 1:3-4 g / mL. The mixture is then ultrasonically extracted at 50-60℃ for 30-40 min, cooled and filtered, and the filtrate is collected. The residue is subjected to the same ultrasonic extraction twice more. All filtrates are combined, concentrated under reduced pressure, and dried to obtain the Morinda officinalis extract.

[0022] Furthermore, the preparation method of the Gynostemma pentaphyllum extract is as follows: the dried whole herb of Gynostemma pentaphyllum is pulverized, and the powder is mixed with 50-60% v / v ethanol at a material-to-liquid ratio of 1:15-20 g / mL and soaked for 4-5 hours. Then, the mixture is stirred and refluxed at 60-65℃ for 2-3 hours, and the reflux extraction is repeated 2-3 times. All extracts are combined, concentrated under reduced pressure, and dried to obtain the Gynostemma pentaphyllum extract.

[0023] Furthermore, the preparation method of the Curculigo extract is as follows: the dried Curculigo rhizome is pulverized, and the Gynostemma pentaphyllum powder and 70-80% v / v ethanol are mixed and soaked for 4-5 hours according to the material-to-liquid ratio of 1:20-25 g / mL. Then, the mixture is stirred and refluxed at 80-85℃ for 2-2.5 hours, and refluxed for a total of 2-3 times. All extracts are combined, concentrated under reduced pressure, and dried to obtain the Gynostemma pentaphyllum extract.

[0024] Compared with the prior art, the beneficial effects of the present invention are: This invention guides the seedlings of the Oriental Wind Snail to gradually adapt to the breeding environment by controlling environmental conditions, reducing the stress impact caused by sudden environmental changes. Furthermore, by using appropriate compound feed and anti-stress agents, it can effectively promote the growth and development of the seedlings' immune organs, regulate the balance of intestinal flora, promote the digestion and absorption of nutrients, improve metabolic efficiency, enhance the body's immunity, thereby improving their stress resistance and effectively reducing mortality.

[0025] In the breeding process, the present invention can create a healthy and clean water environment with beneficial bacteria by spraying compound bacterial solution, and can provide rich nutrition for the seedlings, which is conducive to the growth of juvenile snails.

[0026] The compound feed of this invention combines polysaccharides composed of specific Apocynum venetum polysaccharides, Sorbus nigra polysaccharides, and Fucoidan with raw materials such as Rhodotorula buergerianum and glucuronide. On the one hand, it can regulate the intestinal flora of juvenile snails and activate related enzymes to protect the liver and increase the immunity of juvenile snails. On the other hand, it can also enhance the activity of digestive enzymes and promote their absorption and utilization of nutrients, thereby comprehensively improving the stress resistance of juvenile snail seedlings during the breeding process, effectively reducing mortality and promoting their growth and development. Detailed Implementation

[0027] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.

[0028] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.

[0029] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0030] The Rhodotorula rubra var. CCTCC AY 207027 was derived from the China Center for Type Culture Collection.

[0031] *Pseudomonas aeruginosa* MCCC 1G00113 was obtained from the China Marine Microbial Culture Collection Center; *Bacillus subtilis* was obtained from Beihai Qiangxing Biotechnology Co., Ltd., with an effective viable count ≥100 billion / gram; *Lactobacillus acidophilus* was obtained from Shandong Xinzhuoyuan Biotechnology Co., Ltd., with an effective viable count ≥10 billion / gram.

[0032] Example 1 A method for improving the stress resistance of fallen seedlings of the Oriental Wind Snail includes the following steps: (1) After cleaning the aquaculture pond, expose it to the sun. Then, lay a sieve cloth and a 2cm thick sand layer on the bottom of the pond. The sand layer consists of sea sand, ceramsite, and zeolite powder in a mass ratio of 7:0.4:1. Then, inject seawater, control the water temperature at 25℃, the salinity at 26‰, and the dissolved oxygen at ≥6mg / L. The concentration of seawater is 150mL / m 3 The amount of compound probiotic solution is sprayed; the raw materials of the compound probiotic solution include: *Pseudomonas aeruginosa*, *Bacillus subtilis*, *Lactobacillus acidophilus*, glucose, and water; wherein, the mass ratio of glucose to water is 1:10, and the concentration of *Pseudomonas aeruginosa* is 5 × 10⁻⁶. 5 The concentration of Bacillus subtilis was 1.0 × 10⁻⁶ CFU / mL. 9The concentration of Lactobacillus acidophilus was 5.0 × 10 CFU / mL. 6 CFU / mL; (2) Transfer the seedlings along with the attached sand to the aquaculture pond. Do not feed them any feed within 48 hours of the transfer. Start feeding them compound feed 24 hours after the transfer. For the first 15 days after the transfer, feed them 1g / m³ of compound feed. 3 Feed the animal with formulated feed twice a day (9:00 AM and 5:00 PM). After 15 days of transplanting, feed at a rate of 2g / m³. 3 Feed the animal with formulated feed twice a day (at 9:00 AM and 5:00 PM), at a rate of 1 g / m³. 3 Feed the fish with fresh frozen bait once a day (at 5 PM); check feeding status 1 hour after feeding, and clean up any uneaten bait promptly; the formulated feed includes the following ingredients by weight: 30 parts fish meal, 12 parts corn gluten meal, 2 parts Rhizopus spp. yeast, 3 parts polysaccharide, 0.08 parts glucuronide lactone, 0.62 parts compound amino acids, 3 parts carboxymethyl cellulose, 5 parts sodium alginate, and 3 parts gelatin; among which, the compound amino acids include threonine, glutamic acid, valine, alanine, and glycine in a mass ratio of 0.1:1:0.5:3:1, the polysaccharides include Apocynum venetum polysaccharide, Sorbus niger polysaccharide, and fucoidan in a mass ratio of 4:4:2, and the fresh frozen bait is squid; (3) During the breeding period, administer 0.3g / m every 3 days. 3 The dosage of the anti-stress preparation is administered once; the anti-stress preparation includes a complex polysaccharide and a traditional Chinese medicine extract in a mass ratio of 2:10. The complex polysaccharide includes Apocynum venetum polysaccharide, Sorbus nigra polysaccharide and Lycium barbarum polysaccharide in a mass ratio of 6:3:2. The traditional Chinese medicine extract includes Morinda officinalis extract, Gynostemma pentaphyllum extract and Curculigo orchioides extract in a mass ratio of 7:3:3.

[0033] Example 2 A method for improving the stress resistance of fallen seedlings of the Oriental Wind Snail includes the following steps: (1) After cleaning the aquaculture pond, expose it to the sun. Then, lay a sieve cloth and a 3cm thick sand layer on the bottom of the pond. The sand layer consists of sea sand, ceramsite, and zeolite powder in a mass ratio of 9:0.5:2. Then, inject seawater and control the water temperature to 28℃, salinity to 32‰, and dissolved oxygen ≥6mg / L. The concentration of seawater should be 200mL / m 3 The amount of compound probiotic solution sprayed is as follows: The raw materials of the compound probiotic solution include: *Pseudomonas aeruginosa*, *Bacillus subtilis*, *Lactobacillus acidophilus*, glucose, and water. The mass ratio of glucose to water is 2:10, and the concentration of *Pseudomonas aeruginosa* is 1×10⁻⁶. 6 The concentration of Bacillus subtilis was 2.0 × 10⁻⁶ CFU / mL. 9 The concentration of Lactobacillus acidophilus was 2.0 × 10 CFU / mL. 7 CFU / mL; (2) Transfer the seedlings along with the attached sand to the aquaculture pond. Do not feed them any feed within 48 hours of the transfer. Start feeding them compound feed 24 hours after the transfer. For the first 15 days after the transfer, feed them 1.5g / m³ of compound feed. 3 Feed the animal with formulated feed twice a day (at 9:00 AM and 5:00 PM). After 15 days of transplanting, feed at a rate of 3g / m³. 3 Feed the animal with formulated feed twice a day (at 9:00 AM and 5:00 PM), at a rate of 1.2 g / m³. 3 Feed the animals with fresh, chilled bait once a day (at 5 PM); check their feeding status one hour after feeding and remove any uneaten bait promptly; the formulated feed includes the following ingredients by weight: 40 parts fish meal, 16 parts corn gluten meal, 3 parts Rhizopus spp. yeast, 5 parts polysaccharide, 0.12 parts glucuronide lactone, 1.2 parts compound amino acids, 5 parts carboxymethyl cellulose, 7 parts sodium alginate, and 5 parts gelatin; among which, the compound amino acids include threonine, glutamic acid, valine, alanine, and glycine in a mass ratio of 0.2:2:1:5:2, the polysaccharides include Apocynum venetum polysaccharide, Sorbus niger polysaccharide, and fucoidan in a mass ratio of 8:8:4, and the fresh, chilled bait is a mixture of miscellaneous fish and shrimp meat in a mass ratio of 1:1; (3) During the breeding period, administer 0.5g / m every 3 days. 3 The dosage of the anti-stress preparation is administered once; the anti-stress preparation includes a complex polysaccharide and a traditional Chinese medicine extract in a mass ratio of 4:12. The complex polysaccharide includes Apocynum venetum polysaccharide, Sorbus nigra polysaccharide and Lycium barbarum polysaccharide in a mass ratio of 9:4:5. The traditional Chinese medicine extract includes Morinda officinalis extract, Gynostemma pentaphyllum extract and Curculigo orchioides extract in a mass ratio of 10:5:5.

[0034] Example 3 A method for improving the stress resistance of fallen seedlings of the Oriental Wind Snail includes the following steps: (1) After cleaning the aquaculture pond, expose it to the sun. Then, lay a sieve cloth and a 3cm thick sand layer on the bottom of the pond. The sand layer consists of sea sand, ceramsite, and zeolite powder in a mass ratio of 8:0.5:1.5. Then, inject seawater and control the water temperature to 28℃, salinity to 30‰, and dissolved oxygen ≥6mg / L. The concentration of seawater should be 180mL / m 3 The amount of compound probiotic solution sprayed is as follows: The raw materials of the compound probiotic solution include: *Pseudomonas aeruginosa*, *Bacillus subtilis*, *Lactobacillus acidophilus*, glucose, and water. The mass ratio of glucose to water is 2:10, and the concentration of *Pseudomonas aeruginosa* is 1×10⁻⁶. 6 The concentration of Bacillus subtilis was 2.0 × 10⁻⁶ CFU / mL. 9 CFU / mL, the concentration of Lactobacillus acidophilus is 1.0 × 10⁻⁶. 7 CFU / mL; (2) Transfer the seedlings along with the attached sand to the aquaculture pond. Do not feed them any feed within 48 hours of transfer. Start feeding them compound feed 24 hours after transfer. For the first 15 days after transfer, feed them 1.4 g / m³. 3 Feed the animal with formulated feed twice a day (at 9:00 AM and 5:00 PM). After 15 days of transplantation, increase the feed dosage to 2.5 g / m³. 3 Feed the animal with formulated feed twice a day (at 9:00 AM and 5:00 PM), at a rate of 1.2 g / m³. 3 Feed the animals with fresh, chilled bait once a day (at 5 PM); check their feeding status one hour after feeding and remove any uneaten bait promptly; the formulated feed includes the following ingredients by weight: 36 parts fish meal, 15 parts corn gluten meal, 2 parts Rhizopus spp. yeast, 5 parts polysaccharide, 0.1 parts glucuronide lactone, 1.2 parts compound amino acids, 4 parts carboxymethyl cellulose, 6 parts sodium alginate, and 4 parts gelatin; among which, the compound amino acids include threonine, glutamic acid, valine, alanine, and glycine in a mass ratio of 0.2:1.5:0.8:4:2, the polysaccharides include Apocynum venetum polysaccharide, Sorbus niger polysaccharide, and fucoidan in a mass ratio of 6:5:3, and the fresh, chilled bait is shrimp meat and crab meat in a mass ratio of 1:1; (3) During the breeding period, administer 0.4g / m every 3 days. 3 The dosage of the anti-stress preparation is administered once; the anti-stress preparation includes a complex polysaccharide and a traditional Chinese medicine extract in a mass ratio of 3:12. The complex polysaccharide includes Apocynum venetum polysaccharide, Sorbus nigra polysaccharide and Lycium barbarum polysaccharide in a mass ratio of 8:4:4. The traditional Chinese medicine extract includes Morinda officinalis extract, Gynostemma pentaphyllum extract and Curculigo orchioides extract in a mass ratio of 8:3:5.

[0035] Comparative Example 1 The difference between this comparative example and Example 3 is that the compound feed does not contain polysaccharides. The compound feed of this comparative example includes the following ingredients in parts by weight: 36 parts fish meal, 15 parts corn gluten meal, 2 parts Rhizopus spp., 0.1 parts glucuronide, 1.2 parts compound amino acids, 4 parts carboxymethyl cellulose, 6 parts sodium alginate, and 4 parts gelatin.

[0036] Comparative Example 2 This comparative example differs from Example 3 in that the polysaccharide in the compound feed is only fucoidan. Everything else remains unchanged.

[0037] Comparative Example 3 The difference between this comparative example and Example 3 is that the raw material composition of the compound feed was changed. The compound feed of this comparative example includes the following raw materials in parts by weight: 24 parts fish meal, 38 parts corn gluten meal, 2 parts Rhizopus spp., 1 part polysaccharide, 0 parts glucuronide, 0.3 parts compound amino acids, 1 part carboxymethyl cellulose, 1 part sodium alginate, and 6 parts gelatin.

[0038] Comparative Example 4 This comparative example differs from Example 3 in that no anti-stress agent was administered.

[0039] Comparative Example 5 The difference between this comparative example and Example 3 is that the anti-stress preparation contains only traditional Chinese medicine extracts.

[0040] Comparative Example 6 Compared with Example 3, the difference in this comparative example is that the anti-stress preparation contains only Lycium barbarum polysaccharide and Morinda officinalis extract, with a mass ratio of Lycium barbarum polysaccharide to Morinda officinalis extract of 1:4.

[0041] Aquaculture trial situation Undamaged, healthy juvenile snails with a shell height of approximately 8 mm (species: *Bellamya squarrosa*) were selected as the culture species and cultured using the methods described in the above-mentioned embodiments and comparative examples. 500 juvenile snails were raised in each embodiment and comparative example.

[0042] Before the breeding experiment, 30 samples were randomly selected from each example and comparative group to measure shell height and body weight, and the initial shell height (mm) and initial snail body weight (g) were calculated. After 30 days of breeding according to the above method, the mortality rate of juvenile snails in each group was counted, and the survival rate was calculated. 30 juvenile snails were randomly selected from each group to measure the final shell height (mm) and final snail body weight (g), and the shell height growth rate and weight gain rate were calculated. The average value of the calculation results was taken. Then, the juvenile snails were flash-frozen in liquid nitrogen and stored in an ultra-low temperature freezer at -80°C for testing. Before testing, samples were thawed from an ultra-low temperature freezer, and then the visceral mass was removed, washed with physiological saline, and weighed. Under ice bath conditions, physiological saline was added to the visceral mass at a weight-to-volume ratio of 1 g:9 mL to prepare a tissue homogenate. The homogenate was then centrifuged (4℃, 3000 rpm for 10 min). The supernatant was collected, and the activities of amylase (AMS), lipase (LPS), and trypsin (TRYP), as well as the contents of superoxide dismutase (SOD) and catalase (CAT), were determined according to the kit instructions. The results are shown in Tables 1 and 2 below.

[0043] Shell height growth rate = 100 × (Ht - H0) / H0, where H0 is the initial shell mass in mm; Ht is the final shell mass in mm.

[0044] Weight gain rate % = 100 × (Wt - W0) / W0, where W0 is the initial screw mass in g; Wt is the final screw mass in g.

[0045] Survival rate % = 100 × (N2 / N1), where N1 is the initial number of screws and N2 is the final number of screws.

[0046] Table 1

[0047] As shown in Table 1, compared with Comparative Examples 1-6, Examples 1-3 of the present invention, through the combined use of specific compound feed and anti-stress agents, can effectively promote the growth and development of immune organs in seedlings, regulate the balance of intestinal flora, promote the digestion and absorption of nutrients, improve metabolic efficiency, enhance the body's immunity, effectively reduce mortality, and promote growth and development.

[0048] Table 2

[0049] As shown in Table 2, compared with Comparative Examples 1-6, Examples 1-3 of the present invention, by adding polysaccharides composed of Apocynum venetum polysaccharide, Sorbus nigra polysaccharide and Fucoidan in a mass ratio of 4-8:4-8:2-4, and an anti-stress preparation composed of a complex polysaccharide and traditional Chinese medicine extracts in a mass ratio of 2-4:10-12, can to a certain extent improve the intestinal flora balance of juvenile Rosa rotundifolia, increase the activity of amylase, lipase and trypsin, thereby increasing the digestion, absorption and metabolism of nutrients by juvenile snails, thus promoting the growth and development of juvenile snails. Furthermore, it can increase the activity of enzymes such as superoxide dismutase and catalase, reduce oxidative damage to the body, enhance the body's immunity, and enable juvenile Rosa rotundifolia to gradually adapt to the external environment and improve their anti-stress ability.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for improving the stress resistance of *Bellamya aegyptiaca* seedlings after they have fallen to the ground, characterized in that... Includes the following steps: (1) After cleaning the aquaculture pond, expose it to the sun, lay the sieve cloth and sand layer on the bottom of the pond in sequence, pour in seawater, and sprinkle compound probiotic liquid; (2) Transfer the seedlings along with the attached sand to the breeding pond. Feed them with compound feed for the first 15 days after the transfer. After 15 days, feed them with compound feed and fresh bait. The compound feed includes the following ingredients by weight: 30-40 parts fish meal, 12-16 parts corn gluten meal, 2-3 parts Rhizopus spp., 3-5 parts polysaccharide, 0.08-0.12 parts glucuronide, 0.6-1.2 parts compound amino acids, 3-5 parts carboxymethyl cellulose, 5-7 parts sodium alginate, and 3-5 parts gelatin. (3) During the breeding period, administer anti-stress agents once every 3 days.

2. The method for improving the stress resistance of *Bellamya aegyptiaca* seedlings according to claim 1, characterized in that, The sand layer is 2-3 cm thick; the sand layer is composed of sea sand, ceramsite, and zeolite powder in a mass ratio of 7-9:0.4-0.5:1-2; the compound probiotic liquid is sprayed at a rate of 150-200 mL / m³. 3 During the first 15 days after transfer, the amount of compound feed should be 1~1.5g / m³. 3 ; 15 days after transfer, the amount of compound feed should be 2-3g / m³. 3 The feeding amount of the chilled bait is 1~1.2g / m³. 3 The dosage of the anti-stress agent is 0.3~0.5 g / m³. 3 .

3. The method for improving the stress resistance of *Bellamya aegyptiaca* seedlings according to claim 1, characterized in that, After seawater is injected, the water temperature is controlled at 25~28℃, the salinity at 26~32‰, and the dissolved oxygen at ≥6mg / L.

4. The method for improving the stress resistance of *Bellamya aegyptiaca* seedlings according to claim 1, characterized in that, The raw materials of the compound probiotic liquid include: *Pseudomonas aeruginosa*, *Bacillus subtilis*, *Lactobacillus acidophilus*, glucose, and water, wherein the mass ratio of glucose to water is 1-2:10; and the concentration of *Pseudomonas aeruginosa* is 5 × 10⁻⁶. 5 ~1×10 6 CFU / mL; the concentration of Bacillus subtilis is 1.0~2.0×10⁻⁶ CFU / mL. 9 CFU / mL; the concentration of the Lactobacillus acidophilus was 5.0 × 10⁻⁶. 6 ~2.0×10 7 CFU / mL.

5. The method for improving the stress resistance of *Bellamya aegyptiaca* seedlings according to claim 1, characterized in that, The compound feed comprises the following raw materials in parts by weight: 36 parts fish meal, 15 parts corn gluten meal, 2 parts Rhizopus spp., 5 parts polysaccharide, 0.1 parts glucuronide, 1.2 parts compound amino acids, 4 parts carboxymethyl cellulose, 6 parts sodium alginate, and 4 parts gelatin.

6. The method for improving the stress resistance of *Bellamya aegyptiaca* seedlings according to claim 5, characterized in that, The complex amino acids include threonine, glutamic acid, valine, alanine, and glycine in a mass ratio of 0.1~0.2:1~2:0.5~1:3~5:1~2.

7. The method for improving the stress resistance of *Bellamya aegyptiaca* seedlings according to claim 5, characterized in that, The polysaccharides include Apocynum venetum polysaccharide, Sorbus nigra polysaccharide, and Fucoidan in a mass ratio of 4~8:4~8:2~4.

8. The method for improving the stress resistance of *Bellamya aegyptiaca* seedlings according to claim 1, characterized in that, The chilled bait is one or more of squid, miscellaneous fish, shrimp meat, and crab meat.

9. The method for improving the stress resistance of *Bellamya aegyptiaca* seedlings according to claim 1, characterized in that, The anti-stress preparation comprises a complex polysaccharide and a traditional Chinese medicine extract in a mass ratio of 2-4:10-12.

10. The method for improving the stress resistance of *Bellamya aegyptiaca* seedlings according to claim 1, characterized in that, The complex polysaccharide includes Apocynum venetum polysaccharide, Sorbus nigra polysaccharide and Lycium barbarum polysaccharide in a mass ratio of 6~9:3~4:2~5; the traditional Chinese medicine extract includes Morinda officinalis extract, Gynostemma pentaphyllum extract and Curculigo orchioides extract in a mass ratio of 7~10:3~5:3~5.

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