Artificial breeding method for echinococcal

Abstract

The invention discloses an artificial breeding method for echinococcal snails, which is characterized in that young echinococcal snails are bred in a land-based environment through technical links of parent collection, parent domestication, mating pairing, embryonic development in oocysts, larva culture, filial generation breeding and the like, and a technical guarantee is provided for resource increase and breeding potential evaluation in the future. According to the method, a set of artificial breeding technical system is constructed by combining the physiological habits and breeding characteristics of the echinococcal snails (thousand hand snails) in a natural environment. The method has the characteristics of simple operation and easy popularization. According to the method, the international dispute of the artificial breeding technology of the spinous snails is solved, the domestic blank is filled up, and the field of China is promoted to reach the international leading level.

Description

Technical field:

[0001] The invention relates to the technical field of development and utilization of shellfish germplasm resources in marine agriculture, and in particular to an artificial breeding method for spiny snails. Background technology:

[0002] Chicoreus ramosus, also known as the giant ramosus, belongs to the genus Chicoreus in the subfamily Murexinae of the superfamily Murexidae. This marine gastropod is known for its huge shell, with a body height of 20 to 30 cm, and some individuals even exceeding 30 cm, and a weight of 1000-3000g. It is second only to the Australian conch in size, and is comparable to the crown conch and French conch.

[0003] From the perspective of its origin, the giant hand snail spans multiple ocean regions, from the Red Sea to the east coast of South Africa, the warm waters of the Gulf of Oman to the coral reefs of the Aldabra Atoll, to the vast waters of the central western Pacific including Eastern Polynesia, as well as southern Japan, New Caledonia in Melanesia, and the coastal waters of Queensland in northeastern Australia (Poutiers, 1998, Mostafa et al., 2013, Salas and Chakraborty, 2020). In the South China Sea, there are some natural populations of giant hand snails that live in the intertidal zone of sea reefs; interestingly, they often use rocks, sand and silt as shelter.

[0004] The giant murex is not only an important species in tropical and subtropical marine ecosystems, but also has delicious meat and is expensive, making it one of the main sources of economic benefits in island and reef fisheries. At the same time, due to its exquisite shell design, covered with thick and thorny protrusions, these protrusions have different shapes, similar to leaves or branches, and echo the thousand-hand features on typical murex shells, making it an important handicraft and once occupied an important position in the global shell handicraft market. For example, it is sold in Fiji, Palau, Sabah and other places.

[0005] Given the dual benefits of the thorn snail (Big Thousand Hand Snail) in terms of meat quality (economic benefits) and shells (technological effects), with the increasingly mature diving hunting technology, the global Thousand Hand Snail resources have sharply decreased, some sea areas have become functionally extinct, and the number of Thousand Hand Snails in most sea areas is very rare. For this reason, it is imperative to carry out research and development of artificial breeding technology for thorn snails (Big Thousand Hand Snails). On the one hand, it can increase the amount of thorn snail resources and enhance the diversity and stability of marine ecosystems; on the other hand, it can provide technical support for the utilization of its breeding potential, promote it to become a high-end snail industry alternative species, and maintain the healthy and sustainable development of its shellfish industry.

[0006] However, there is no report on the artificial breeding method of spiny snails so far. Summary of the invention:

[0007] The invention aims to provide a method for artificially breeding spiny snails.

[0008] The present invention is achieved through the following technical solutions:

[0009] A method for artificially breeding spiny snails, the method comprising the following steps:

[0010] a. Parent collection: Parents were collected by diving in the waters of Daya Bay in Shenzhen, Leizhou Peninsula in Zhanjiang, and the archipelago waters of the Xisha Islands in Hainan. Individuals with a shell height of more than 20 cm, 1-3 kg, and strong gastropod adhesion were selected as parents;

[0011] b. Parent transportation and domestication: The parents are airlifted to the culture pond at a low temperature of 4-8℃ and fasted in micro-flow water for 2-3 days; then bivalve mollusks are regularly fed at 6.00-7.00 pm as food, with the feeding amount being 4-6% of the total weight of the parents; leftover bait and feces are cleaned every day to ensure clear and fresh water quality; the water quality conditions of the culture pond are 23-30℃, salinity 28-32ppt, and pH 8.00-8.50;

[0012] c. Mating: After the parents have adapted to the environment, they will mate. The male inserts his penis into the female's spermatheca, releases sperm, and combines with the egg to complete fertilization. There may also be a phenomenon where a female is fertilized by multiple males, after which the female produces an egg sac containing fertilized eggs ( Figure 1 );

[0013] d. Embryonic development in the egg capsule: After the egg capsule is found, the mother snail is transferred to the hatching pond for egg capsule discharge. After 5-10 days, the egg capsule is discharged. The mother snail protects the eggs until the egg capsule is hatched. The egg capsule is light yellow in color at first, and turns gray-black after 25-28 days, which means that the mid-stage veliger larvae are about to be released ( Figure 2 , Figure 3 ); the offspring in the oocyst went through the stages of fertilized egg, first polar body, second polar body, 2-cell stage, 4-cell stage, 8-cell stage, multi-cell stage, blastocyst stage, gastrula stage, trochophore stage, intramembranous veliger stage, early veliger stage, and mid-veliger stage (Table 1, Figure 4 ); Micro-flow water and micro-gas flow mode were used during the embryonic development in the oocyst, and the whole process was completed under the conditions of water temperature of 27-29°C, salinity of 28-32ppt, and pH 8.00-8.50;

[0014] e. Larval culture: The larvae just released from the egg capsule are mid-stage veliger larvae. Collect the larvae into the larval culture pool and feed them in a micro-aeration and low-feeding mode at a density of 0.2-0.3 / ml. Feed them with unicellular algae such as golden algae and chlorella. The feeding amount depends on the feeding situation. The principle is to ensure that the water quality is clear and transparent before the next feeding. After 25-30 days of culture, they enter the late veliger larvae stage and show behaviors such as veliger atrophy, diving to the bottom of the water body, and crawling with their feet. Figure 4 , Figure 5 ); The entire larval culture process was completed at a water temperature of 26-30°C, a salinity of 28-32ppt, and a pH of 8.10-8.50;

[0015] f. Offspring cultivation: Entering the late stage of the face plate larvae, it gradually transforms into a newly formed juvenile snail. At this time, it has completely lost its face plate, crawls with its feet, and a secondary shell appears; after 9-11 days of development, eyes appear on the antennae, indicating that the transformation into a juvenile snail is complete; after another 10-15 days of development, obvious patterns appear on the secondary shell. Except for the lack of reproductive ability, its appearance is similar to that of an adult, entering the juvenile snail stage; after another 1-2 months of cultivation, 3-5mm seedlings are obtained, and its diet has changed from plant-eating to carnivorous ( Figure 5 ); during the entire offspring cultivation process, micro-flow and micro-aeration culture mode is adopted; the amount of feed is determined according to the feeding situation, and the feeding habit conversion occurs in the juvenile shellfish stage; the water temperature is 25-30℃, the salinity is 29-32ppt, and the pH is 8.06-8.50.

[0016] The parent collection described above can only be carried out by catching in the wild because there is no breeding population and the species currently exists in wild form.

[0017] The purpose of domesticating the parents is to enable them to adapt to the artificial environment so that they can mate, lay eggs, and reproduce under artificial conditions;

[0018] The mating pairing mentioned above mostly occurs at night, and it is also possible for one female to mate with multiple males.

[0019] The embryonic development in the egg capsule is described because this species is different from most other snails in that they develop into early veliger larvae in the egg capsule, but instead they develop directly into mid-stage veliger larvae in the egg capsule.

[0020] The larvae culture presents an intermittent floating mode during the floating period, that is, an alternating mode of floating→sinking→floating→sinking→floating, until the larvae are transformed into young snails, at which time this mode ends.

[0021] In the offspring culture, the young and juvenile snails are crawling and have the property of avoiding light, so they need to be shielded from light; at the same time, an attachment base, such as a corrugated board, a reef, etc., needs to be placed, which can effectively improve the survival rate and growth rate of the offspring.

[0022] The beneficial effects of the present invention are as follows: The present invention cultivates its young snail seedlings in a land-based environment through the technical links of parent collection, parent domestication, mating pairing, embryo development in egg sacs, larval culture, and offspring cultivation, providing technical guarantee for future resource increase and breeding potential assessment. The present invention combines the physiological habits and reproductive characteristics of the spiny snail (Big Thousand Hand Snail) in the natural environment to construct a set of artificial breeding technology system. It has the characteristics of simple operation and easy promotion. The present invention solves the international disputes existing in the artificial breeding technology of spiny snails, fills the domestic gap, and promotes my country to reach the international leading level in this field. Description of the drawings:

[0023] Figure 1 The parent of the spiny snail (Big Hand Snail) and its egg-laying process in Example 1;

[0024] Among them, A, parental mating and spawning; B, parental morphology; CD, spawning; E, egg protection behavior; F, egg sac.

[0025] Figure 2 The color, shape, size of the oocyst and the eggs inside it;

[0026] Among them, A, oocyst; B, light yellow is normal oocyst, blue-black is necrotic oocyst; C, unfertilized egg; D, fertilized egg.

[0027] Figure 3 It is the color change of the egg sac during the hatching process;

[0028] Among them, A, newly laid oocyst; B, 5-7 day oocyst; C, 12-15 day oocyst; D, 15-20 day oocyst (mature oocyst).

[0029] Figure 4 This is the life history of the early stage of the spiny snail (Big Thousand Hand Snail);

[0030] Among them, A, fertilized egg; B, 2 cells; C, 4 cells; D, multi-cell stage; E, blastocyst stage; F, gastrula stage; G, trochophore larvae, H, intramembranous veliger larvae; I, early veliger larvae; L, mid-stage veliger larvae; M, late-stage veliger larvae; N, about to form a juvenile snail; O, juvenile snail; P, just formed a juvenile snail; Q, juvenile snail.

[0031] Figure 5 It is the development of offspring after the release of the oocyst;

[0032] Among them, A, mid-stage veliger larva; B, late-stage veliger larva; C, juvenile snail; D, young snail. Specific implementation method:

[0033] The following is a further description of the present invention, rather than a limitation of the present invention.

[0034] Embodiment 1:

[0035] a. Parent collection: On March 9, 2024, 9 spiny snails (Big Thousand Hand Snails) were collected by diving in the waters of Daya Bay, Shenzhen. The shell height was 20-30cm and the total weight was 1.0-2.0kg / piece. The individuals were fresh and vigorous, and their ventral feet had a strong ability to grasp the bottom wall;

[0036] b. Parent domestication: The parents were transported to the breeding pond of the Daya Bay Marine Biological Comprehensive Experimental Station of the Chinese Academy of Sciences at a low temperature of 4-8℃ and fasted for 2 days in micro-flow water; then they were fed with Manila clams as food at 6:00 pm; the feeding amount was 5% of the total weight of the parents, and the leftover bait and feces were cleaned every day to ensure clear and fresh water quality; the seawater quality conditions were water temperature 23-27℃, salinity 28-30ppt, pH 8.00-8.30;

[0037] c. Mating: After the parents adapted to the environment, they mated on June 3, 2024. The male inserted his penis into the female's spermatheca, released sperm, and combined with the egg to complete fertilization. It was also found that one female was fertilized by three males, and then the female produced an egg sac containing fertilized eggs ( Figure 1 );

[0038] d. Embryonic development in the egg sac: After the egg sac is found, the mother snail is transferred to the hatching pond for egg sac discharge. The egg sac is attached to the wall of the pond and arranged neatly. After 7 days, the egg sac discharge behavior is completed, and a total of 620 egg sacs are discharged. Each egg sac contains 500-600 fertilized eggs. The mother snail has the behavior of protecting the eggs until the egg sac is hatched. The egg sac is light yellow at first, and turns gray-black after about 28 days, which means that the mid-stage veliger larvae are about to be released ( Figure 2 , Figure 3 ); the offspring in the oocyst went through the stages of fertilized egg, first polar body, second polar body, 2-cell stage, 4-cell stage, 8-cell stage, multi-cell stage, blastocyst stage, gastrula stage, trochophore stage, intramembranous veliger stage, early veliger stage, and mid-veliger stage (Table 1, Figure 4 ); The embryonic development stage in the oocyst is carried out in a micro-flow and micro-aeration mode, and the whole process is completed under the conditions of water temperature 27-29°C, salinity 28-32ppt, and pH 8.10-8.40;

[0039] e. Larval culture: The larvae just released from the egg capsule are mid-stage veliger larvae, with a shell height of 660-670μm; the larvae are collected in a 1.5 cubic meter larval culture pool using a scoop net, and are raised in a micro-aeration and low-feeding mode at a density of 0.2 / ml; they are fed with two types of unicellular algae, golden algae and chlorella, and the feeding amount is determined according to the feeding situation. The principle is to ensure that the water quality is clear and transparent before the next feeding; after 30 days of culture, the shell height is 720-730μm, entering the late veliger larvae stage, showing behaviors such as veliger atrophy, diving to the bottom of the water body, and crawling with feet ( Figure 4 , Figure 5 ), and put corrugated board as the seedling attachment base. The whole cultivation process is completed at a water temperature of 27-30℃, a salinity of 29-32ppt, and a pH of 8.10-8.40;

[0040] f. Offspring cultivation: When it enters the late stage of the face disc larvae in step e, it gradually transforms into a newly formed young snail with a shell height of about 950μm. At this time, it has completely lost its face disc and crawls with its feet, and a secondary shell appears; after 10 days of development, eyes appear on the antennae, indicating that the transformation into a young snail is complete, and the shell height is about 1100μm; after another 10 days of development, obvious patterns appear on the secondary shell. Except for the lack of reproductive ability, its appearance is similar to that of an adult, and it has entered the young snail stage, with an initial size of about 1200μm; after 2 months of cultivation, 3236 3-5mm seedlings were obtained, and its diet has changed from plant to carnivorous ( Figure 5 ). During the entire offspring cultivation process, a micro-flow water and micro-aeration culture mode is adopted; the amount of feed is determined according to the feeding situation, and the feeding habit conversion occurs in the juvenile shellfish stage; the water temperature is 25-30℃, the salinity is 29-32ppt, and the pH is 8.13-8.50.

[0041] Table 1 Developmental stages, size and time of the early life cycle of the spiny snail (Echinochloa sphenanthera)

[0042]

[0043]

[0044] Example 2

[0045] a. Parent collection: On June 1, 2024, 12 spiny snails (Big Thousand Hand Snails) were collected by diving in the waters of Xuwen, Zhanjiang. The shell height was 20-30cm and the total weight was 1.0-3.0kg / piece. The individuals were fresh and vigorous, and their ventral feet had a strong ability to grasp and suck the bottom wall;

[0046] b. Parent domestication: The parents were airlifted to the breeding pond of the Daya Bay Marine Biological Comprehensive Experimental Station of the Chinese Academy of Sciences at a low temperature of 4-8℃ and fasted for 3 days in micro-flow water; then they were fed with Manila clams as food at 7:00 pm; the feeding amount was 5% of the total weight of the parents, and the leftover bait and feces were cleaned up every day to ensure clear and fresh water quality; the seawater quality conditions were water temperature 27-28℃, salinity 29-32ppt, pH 8.10-8.50;

[0047] c. Mating: After the parents adapted to the environment, they mated on June 25, 2024. The male inserted his penis into the spermatheca of the female, released sperm, and combined with the eggs to complete fertilization. It was also found that one female fertilized with four males, and then the female produced an egg sac containing fertilized eggs.

[0048] d. Embryonic development in the egg capsule: After the egg capsule is found, the mother snail is transferred to the hatching pond for egg capsule discharge. The egg capsules are neatly arranged on the wall of the pond. After 5 days, the egg capsule discharge behavior is completed, and a total of 816 egg capsules are discharged, each egg capsule contains 400-600 fertilized eggs; the mother snail has the behavior of protecting the eggs until the hatching in the egg capsule is completed; the egg capsule is light yellow in color at first, and after about 25 days, it turns gray-black, which means that the mid-stage veliger larvae are about to be released; the offspring in the egg capsule go through the stages of fertilized egg, first polar body, second polar body, 2-cell stage, 4-cell stage, 8-cell stage, multi-cell stage, blastocyst stage, gastrula stage, trochophore stage, intramembranous veliger larvae stage, early veliger larvae stage, and mid-stage veliger larvae stage; the embryonic development stage in the egg capsule is carried out in a micro-flow and micro-air mode, and the whole process is completed under the conditions of water temperature of 27-29℃, salinity of 28-32ppt, and pH 8.10-8.50;

[0049] e. Larval culture: The larvae just released from the egg capsule are mid-stage veliger larvae, with a shell height of 660-670μm. Use a scoop net to collect the larvae into a 2.0 cubic meter larval culture pool, and feed them at a density of 0.2 / ml in a micro-aeration and low-feeding mode. Feed them with two types of unicellular algae, golden algae and chlorella. The feeding amount depends on the feeding situation. The principle is to ensure that the water quality is clear and transparent before the next feeding. After 25 days of culture, the shell height is 720-730μm, entering the late veliger larvae stage, showing behaviors such as veliger atrophy, diving into the bottom of the water body, and crawling with feet. Cleaned and disinfected reefs are placed as the attachment base for seedling collection. The entire culture process is completed at a water temperature of 27-30℃, a salinity of 30-32ppt, and a pH of 8.10-8.50.

[0050] f. Offspring cultivation: When it enters the late stage of the velar larvae, it gradually transforms into a newly formed juvenile snail, with a shell height of about 950μm. At this time, the velar has been completely lost, and it crawls with its feet, and a secondary shell appears; after 10 days of development, eyes appear on the antennae, which means that it has completed the transformation into a juvenile snail, and the shell height is about 1100μm at this time; after another 12 days of development, obvious patterns appear on the secondary shell. Except for the lack of reproductive ability, its appearance is similar to that of an adult, and it has entered the juvenile snail stage, with an initial size of about 1200μm; after 1 month of cultivation, 6537 3-5mm seedlings were obtained, and its diet has changed from plant to carnivorous. During the entire offspring cultivation process, micro-flow water and micro-aeration cultivation mode is adopted; the amount of bait is determined according to the feeding situation, and the diet conversion occurs in the juvenile shell stage; the water temperature is 26-30℃, the salinity is 29-32ppt, and the pH is 8.10-8.50.

Claims

1. A method for artificial breeding of spiny snails, characterized in that: The method comprises the following steps: a. Parent collection: Parents were collected by diving in the waters of Daya Bay in Shenzhen, Leizhou Peninsula in Zhanjiang, and the archipelago waters of the Xisha Islands in Hainan. Individuals with a shell height of more than 20 cm, 1-3 kg, and strong gastropod adhesion were selected as parents; b. Parent transportation and domestication: The parents are airlifted to the culture pond at a low temperature of 4-8℃ and fasted in micro-flow water for 2-3 days; then bivalve mollusks are regularly fed at 6.00-7.00 pm as food, with the feeding amount being 4-6% of the total weight of the parents; leftover bait and feces are cleaned every day to ensure clear and fresh water quality; the water quality conditions of the culture pond are 23-30℃, salinity 28-32ppt, and pH 8.00-8.50; c. Mating: After the parents have adapted to the environment, they will mate. The male inserts his penis into the female's spermatheca, releases sperm, and combines with the egg to complete fertilization. There may also be a phenomenon where a female is fertilized by multiple males, after which the female produces an egg sac containing fertilized eggs. d. Embryonic development in the egg capsule: After the egg capsule is found, the mother snail is transferred to the hatching pond for egg capsule discharge. After 5-10 days, the egg capsule is produced. The mother snail has the behavior of protecting the eggs until the hatching in the egg capsule is completed. The egg capsule is light yellow in color at first, and after 25-28 days, it turns gray-black, which means that the mid-stage veliger larvae are about to be released. The offspring in the egg capsule go through the stages of fertilized egg, first polar body, second polar body, 2-cell stage, 4-cell stage, 8-cell stage, multi-cell stage, blastocyst stage, gastrula stage, trochophore stage, intramembranous veliger larvae stage, early veliger larvae stage, and mid-stage veliger larvae stage. Micro-flow and micro-aeration mode are used during the embryonic development in the egg capsule. The whole process is completed under the conditions of water temperature of 27-29℃, salinity of 28-32ppt, and pH 8.00-8.

50. e. Larval culture: The larvae just released from the egg capsule are mid-stage veliger larvae. Collect the larvae into the larval culture pool and feed them in a micro-aeration and low-feeding mode at a density of 0.2-0.3 pcs / ml. Feed them with golden algae and chlorella. The feeding amount depends on the feeding situation. The principle is to ensure that the water quality is clear and transparent before the next feeding. After 25-30 days of culture, they enter the late veliger larvae stage, showing veliger atrophy, diving to the bottom of the water body, and crawling with their feet. The whole larval culture process is completed at a water temperature of 26-30℃, a salinity of 28-32ppt, and a pH of 8.10-8.

50. f. Offspring cultivation: When entering the late stage of velar larvae, they gradually transform into newly formed juvenile snails, at which time they have completely lost their velar larvae, crawl with their feet, and a secondary shell appears; after 9-11 days of development, eyes appear on the antennae, indicating that the transformation into juvenile snails is complete; after another 10-15 days of development, obvious patterns appear on the secondary shell, and its appearance is similar to that of an adult, entering the juvenile snail stage; after another 1-2 months of cultivation, 3-5mm seedlings are obtained, and their diet has changed from herbivorous to carnivorous; during the entire offspring cultivation process, micro-flow water and micro-aeration culture modes are used; the amount of bait is determined according to the feeding situation, and the diet conversion occurs in the juvenile shell stage; the water temperature is 25-30℃, the salinity is 29-32ppt, and the pH is 8.06-8.

50.

2. The method according to claim 1, characterized in that The progeny culture needs to be shaded and a substrate needs to be placed.

3. The method according to claim 1, characterized in that: The attachment base is a corrugated board or a reef.

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