Propagation method of babylonia taiwanensis and babylonia lutosa hybrid fry

Abstract

The invention relates to a breeding method for babylonia taiwanensis and babylonia lutosa hybrid seedlings. The breeding method comprises the following steps that babylonia taiwanensis parent snails and babylonia lutosa parent snails are bred in a mixed mode in the dark, vegetables accounting for 3%-5% of the weight of the babylonia lutosa are fed, mixed biological bait accounting for 10%-15% of the weight of the babylonia lutosa is fed, continuous feeding is conducted till gonads are mature, and feeding is conducted at least once every day; the babylonia taiwanensis parent snails and the babylonia lutosa parent snails are hybridized to obtain oocyst clusters; the oocyst clusters are hatched to form planktonic larvae, the planktonic larvae are metamorphosed into juvenile snails after 15-20 days of cultivation, and then hybrid fries are obtained. The hybrid offspring seeds obtained by the breeding method have excellent metamorphosis rate, fertilization rate and hatching rate, and the average body weight, average shell length and survival rate are also remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of shellfish breeding, and more specifically, relates to a method for breeding hybrid seedlings of Taiwan baby shells and mud baby shells. Background Art

[0002] The baby wind snail, also known as sea pig snail, flower snail, etc., is a mollusk of the family Conchidae in the order Stenoglossata. The main types of baby wind snails farmed in my country are the square-spotted baby wind snail, mud baby wind snail and Taiwan baby wind snail. The square-spotted baby wind snail is also called the ivory conch, and its main production areas are the South China Sea and the East China Sea. The mud baby wind snail is also called the mist flower conch, and is mainly distributed in the coastal areas of Zhejiang, Fujian, and Guangdong, and is more common in Fuzhou and Chaoshan areas. The Taiwan baby wind snail is also called the Taiwan conch, and is mainly distributed in the waters of Taiwan, my country.

[0003] Hybrid breeding is essentially the re-aggregation of genetic resources between different parents. It can quickly break the original genetic conservatism and make the hybrids have greater genetic mobility. It is an important way to increase variation and can quickly and significantly improve the vitality, growth and other excellent traits of hybrid offspring. It is of great significance in the genetic improvement of shellfish. Therefore, hybrid breeding has also become an important direction for genetic improvement research of Babylonia conch.

[0004] Patent publication number CN104798709A discloses a method for breeding hybrid seedlings of Babylonia squared, which uses hybridization of Babylonia squared from Thailand and Babylonia south of Hainan to breed hybrid seedlings with fast growth rate and strong disease resistance. Due to the strong disease resistance, breeding hybrid seedlings reduces breeding diseases and avoids the occurrence of diseases such as "swollen kiss disease" and "shelling disease".

[0005] "Progress in Research on Biology and Genetic Breeding of Babylonia, Fu Jingqiang" disclosed that the genetic distance between Babylonia square-spotted, Babylonia mud and Babylonia Taiwan has reached the level of inter-species. In addition, it also mentioned the use of complete double-row hybridization, using the Wengtian population of Babylonia square-spotted in Hainan and the Rayong population of Thailand as materials for long-distance hybridization between populations. The experimental results showed that: in the larval development stage, the hybrid combination showed super-parent advantage in both metamorphosis rate and metamorphosis time, with super-parent advantage rates of 8.7% and 20.53%, respectively. However, the increase in the metamorphosis rate of the above-mentioned hybrid combination is still difficult to meet the actual needs during seedling and breeding. Summary of the invention

[0006] In response to the above-mentioned existing technical problems, the primary purpose of the present invention is to provide a breeding method for hybrid seedlings of Taiwan baby snails and mud baby snails. Compared with the existing Taiwan baby snails and mud baby snails, the hybrid seedlings of Babylonia rapa cultivated by the breeding method not only have a better metamorphosis rate, but also have significantly improved fertilization rate and hatching rate.

[0007] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0008] The present invention claims protection for a method for breeding hybrid seedlings of Babylonia Taiwani and Babylonia Mudalis, comprising the following steps:

[0009] S1. Enhanced cultivation of parent snails: Taiwan Babylonia parent snails and mud Babylonia parent snails are mixed and cultured in the dark, and are fed with vegetables accounting for 3-5% of the body weight of the Babylonia parent snails, and mixed biological bait accounting for 10-15% of the body weight of the Babylonia parent snails, and are continuously fed until the gonads mature, and are fed at least once a day; Taiwan Babylonia parent snails and mud Babylonia parent snails are hybridized to obtain egg capsule clusters;

[0010] S2. Seedling cultivation: The egg capsule clusters hatch to form planktonic larvae. After 15 to 20 days of cultivation, the planktonic larvae metamorphose into juvenile snails, and hybrid seedlings are obtained;

[0011] The mixed biological bait includes, by weight: 10 to 30 parts of clams, 40 to 50 parts of oysters, 5 to 15 parts of sandworms, and 10 to 30 parts of grain worms.

[0012] The present invention firstly mixes the parent snails of Taiwan baby snails and the parent snails of mud baby snails in the dark, so that the baby snails can mate more easily under dark conditions. In the mixed breeding process, vegetables and mixed biological baits are fed to promote the gonadal maturation of the baby snails. The vegetables have the effect of promoting the intestinal tract of the baby snails and are nutritionally balanced; and the mixed biological baits are rich in nutrition and high in protein content, which can accelerate the gonadal maturation of the baby snails and enable the baby snails to lay eggs quickly. The baby snails with mature gonads are hybridized to obtain egg sac clusters, which are hatched and cultivated, and metamorphosed into juvenile snails, that is, hybrid seedlings are obtained.

[0013] The inventors found through research that compared with the existing Taiwan baby snails and mud baby snails, the hybrid baby snails have a better metamorphosis rate, and the fertilization rate and hatching rate are also significantly improved. The fertilization rate of the baby snails is 39% and 23% higher than that of the two existing baby snails, respectively; the hatching rate is 30% and 24% higher; and the metamorphosis rate is 82% and 66% higher.

[0014] Furthermore, the inventors found through research that the average body weight and average shell length of the above-mentioned Dongfeng snail seedlings were significantly improved in the first stage of breeding (intermediate cultivation) and the second stage of breeding (adult snail breeding).

[0015] Specifically, in step S1, male Taiwan Babylonia snails and female mud Babylonia snails can be selected for mixed breeding, or male mud Babylonia snails and female Taiwan Babylonia snails can be selected for mixed breeding. More specifically, male Babylonia snails can be selected from healthy, vigorous, and undamaged Babylonia snails over 3 years old, and female Babylonia snails can be selected from healthy, vigorous, and undamaged Babylonia snails over 2 years old.

[0016] Specifically, in the present invention, the shell surface of the Taiwan Babylonia is light brown, and the pattern is light brown and relatively continuous and irregular; the shell surface of the mud Babylonia is muddy blue-gray, the shell mouth is purple-red, the pattern is unclear, and there is an orange-yellow circle in the center of the operculum. More specifically, the mud Babylonia is the Zhanjiang mud Babylonia.

[0017] Preferably, in step S1, the mixed culture conditions are: ammonia nitrogen concentration ≤ 0.5 mg / L, nitrite concentration ≤ 0.1 mg / L, salinity 28-31, dissolved oxygen ≥ 5 mg / L, calcium ion concentration ≥ 100 mg / L. By adding calcium ions during the mixed culture process, calcium precipitation in the body of the baby snail can be effectively promoted to meet the calcium demand for development and growth.

[0018] Preferably, in step S2, the incubation conditions are: pH 8.3-8.6, dissolved oxygen 5-6 mg / L, water temperature 25-30°C, and seawater specific gravity 1.020-1.014 g / mL.

[0019] Preferably, in step S1, the vegetables are selected from one or more of pakchoi, cabbage, pumpkin, mustard greens, sedge, kale, shepherd's purse, spinach, amaranth, kale, and Chinese cabbage.

[0020] Specifically, Chinese cabbage is an annual or biennial herbaceous plant of the genus Brassica in the family Cruciferae. Its branches are generally hairless; its leaves are obovate, with rounded tips and green outer leaves lying on the ground; its petals are bright yellow and obovate; its fruit is a silique with brown, spherical seeds; its root system is well-developed and grows into a fleshy, fleshy root. Chinese cabbage was originally called song, but because of its bluish-white color, it is also called white cabbage.

[0021] Preferably, in step S1, the mixed biological bait further contains lecithin powder. More specifically, the amount of lecithin powder added is 100-200 mg / kg.

[0022] Preferably, in step S1, the Taiwania taiwanensis and the mudia taiwanensis are mixed and cultured in a male-female ratio of 1:1 to 2.

[0023] Preferably, in step S2, the density of the egg cyst cluster incubation is 0.1 to 0.3 catties / m 3 .

[0024] Preferably, in step S2, during the cultivation period, mixed algae are fed every 2 to 3 times; allicin is fed every 2 to 3 days, and vitamins are added every day.

[0025] Further preferably, the mixed algae includes one or more of Isochrysis Zhanjiangensis, Platymonas, and Thalassiosira. In some specific embodiments, the cell concentration ratio of Isochrysis Zhanjiangensis, Platymonas, and Thalassiosira is 2-6:3-4:3-4, and the cell concentration of the mixed algae is 40,000-80,000 cells / mL. In some specific embodiments, the mixed algae is fed 2-3 times a day.

[0026] More preferably, the feeding amount of allicin is 0.1-0.25 g / m 3 .

[0027] More preferably, the vitamins may be vitamins commonly used in the cultivation of Babylonia snails in the art, such as vitamin E. More specifically, the vitamin feeding amount is 0.1-0.2 g / m 3 .

[0028] Preferably, when the shell length of the planktonic larvae reaches about 1000 microns, shrimp flakes and yeast are added to the bait for feeding. More specifically, the feeding amount of the shrimp flakes is 0.2-0.5 g / m 3 The feeding amount of the yeast is 0.1-0.3 g / m 3 .

[0029] Preferably, in step S2, water flows for 24 hours during the incubation period, and the daily water flow is 100-200% of the volume of the incubation container.

[0030] Further preferably, the water is slowly added and replaced once every 1 to 3 hours in a slight overflow manner after hatching, and the planktonic larvae are ensured not to be adsorbed on the water replacement net bag when adding and replacing the water. The amount of water replaced each time is 20 to 30% of the volume of the hatching bucket.

[0031] Preferably, in step S2, the hybrid seedlings are cultured into adult snails and then mixed, and then cultured using the methods of step S1 and step S2.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention provides a method for propagating hybrid seedlings of Taiwan Babylonia and mud Babylonia. The hybrid seedlings of Babylonia obtained by the above method have excellent metamorphosis rate, fertilization rate and hatching rate, which are significantly higher than those of common Taiwan Babylonia and mud Babylonia. The present invention forms Babylonia seedlings by hybridization cultivation, enriches the germplasm types of Babylonia, and ensures the healthy, green and sustainable development of the Babylonia industry. DETAILED DESCRIPTION

[0034] The present invention is further described below with reference to specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0035] Example 1: Propagation method of hybrid seedlings of Taiwan Babylonia taiwanensis and Zhanjiang mud Babylonia truncatula

[0036] (1) Selection of parent snails: For male snails, choose Taiwan snails that are over 3 years old, healthy, vigorous, and undamaged; for female snails, choose Zhanjiang mud snails that are over 2 years old, healthy, vigorous, and undamaged;

[0037] (2) Pairing: Identify males and females based on their genital pores and copulation organs, and place the snails in a dark breeding box at a ratio of 1:1 between males and females. Control the water parameters as follows: ammonia nitrogen concentration ≤ 0.5 mg / L, nitrite concentration ≤ 0.1 mg / L, salinity 28-31, dissolved oxygen ≥ 5 mg / L, and calcium ion concentration ≥ 100 mg / L;

[0038] (3) Enhanced cultivation of parent snails: Feed once a day, first feed pakchoi accounting for 3% of the snail's body weight, then feed mixed biological bait accounting for 10% of the snail's body weight (by weight, the mixed biological bait includes: 10 parts of clams, 40 parts of oysters, 10 parts of sandworms, and 20 parts of grain worms), and the feeding amount is based on a small amount of surplus. In addition, the mixed biological bait is mixed with 150 mg / kg of lecithin powder and continuously fed until the gonads mature. The entire pond is drained once a day and dried in the shade for 20 minutes.

[0039] (4) Judgment of sexual maturity of parent snails: Patrol and observe the behavior of parent snails several times a day in the morning, noon and evening. If tail-chasing occurs, it means that gonadal maturity has been reached.

[0040] (5) Seedling cultivation: Egg sac clusters were obtained by hybridizing the parent snail of the Taiwan baby snail and the parent snail of the mud baby snail. The collected egg sac clusters were placed in an incubation bucket for incubation. The incubation density of the egg sac clusters was 0.1 catties / m 3 The hatching conditions are as follows: pH 8.3-8.6, dissolved oxygen 5-6 mg / L, water temperature 25-30℃, seawater specific gravity 1.020-1.014 g / mL, fertilized eggs gradually develop into face disc larvae in the egg capsule, and hatching means the larvae break the membrane and become planktonic larvae. The water flows for 24 hours during the hatching period, and the daily water flow is 150% of the volume of the hatching bucket. After hatching, the water is slowly added and changed once every 1-3 hours in a slight overflow manner. When adding and changing water, ensure that the larvae are not adsorbed on the water change net bag. The amount of water changed each time is 20% of the volume of the hatching bucket. Feed 2-3 times a day, with Zhanjiang Isochrysis, Platymonas, and Thalassiosira as bait. The cell concentration ratio of the three algae is 2:3:3, and the algae cell concentration is 60,000 cells / ml. Feed when the water body is microalgae, and feed once every 2 days with 0.1g / m 3 Allicin, add 0.1g / m per day 3 Vitamin E: When the shell length of the planktonic larvae reaches about 1000 microns, 0.3g / m3 of vitamin E should be added to the bait. 3 Shrimp chips and 0.2g / m 3Yeast. After 16 days of cultivation, the larvae metamorphose into crawling young snails, which are hybrid seedlings.

[0041] Example 2: Propagation method of hybrid seedlings of Babylonia Taiwana and Babylonia Zhanjiangensis

[0042] The difference between this embodiment and embodiment 1 is that the male babylonia snails are selected from the Zhanjiang mud babylonia snails, and the female babylonia snails are selected from the Taiwan babylonia snails.

[0043] Example 3: Cultivation of hybrid seedlings

[0044] Hollow bricks are evenly laid on the bottom of the breeding pond, and the sieve plate is placed on the hollow bricks. The sleeve is inserted into the fixed hole of the sieve plate frame, so that one end of the sleeve is on the top and the other end is under the bottom of the sieve plate frame. A layer of 80-mesh silk cloth is laid on the sieve plate frame to prevent sand from flowing to the bottom layer through the sieve plate frame. A 4-cm thick sand layer (sand particle size is 0.8-1.5mm) is evenly laid on the silk cloth to divide the breeding water into two layers. A PVC sprinkler pipe is hung above the breeding pond to spray water, with a flow rate of 5m 3 / h, the water replacement volume in 24 hours is 3-5 times the original water volume. Two PVC air pipes with a hole diameter of 1.5cm are laid on the bottom substrate of the pool. A hole with a hole diameter of 0.1mm is drilled on the upper side of the pipe wall for air filling. Continuous air filling for 24 hours makes the dissolved oxygen content in the pool water about 5mg / L.

[0045] In the first stage of cultivation, the hybrid seedlings bred in Example 1 with a shell length of about 1 mm are selected, and 15,000 young snails are placed per square meter for intermediate cultivation. During this period, 100 grams of oyster meat is fed per kilogram of Dongfeng snails, and the feeding is once a day for a period of 1 month. After the intermediate cultivation is completed, the young snails with uniform shell length of about 1 cm are screened out in the corresponding breeding pond with a sieve basket and placed in each 16 square meter breeding pond at 1,250 per square, and the second stage of adult snail cultivation is started. Feed once every 2 days, and feed 130 grams of Balang fish per kilogram of Dongfeng snails for a period of 8 months.

[0046] At the end of the two stages, 200 snails were randomly caught in each pond for weighing and other body measurement tests to compare their growth at different stages.

[0047] Example 4: Cultivation of hybrid seedlings

[0048] The difference between this embodiment and embodiment 3 is that the hybrid seedlings in embodiment 2 with a shell length of about 1 mm are selected.

[0049] Comparative Example 1

[0050] The difference between this comparative example and Example 1 is that both the male and female babylonia snails are Babylonia Taiwanica.

[0051] Comparative Example 2

[0052] The difference between this comparative example and Example 1 is that both the male and female babylonia snails are selected from the Zhanjiang mud babylonia snails.

[0053] Comparative Example 3

[0054] The difference between this comparative example and Example 3 is that the Taiwan baby snail seedlings in Comparative Example 1 are used to replace the hybrid seedlings in Example 1.

[0055] Comparative Example 4

[0056] The difference between this comparative example and Example 3 is that the hybrid seedlings in Example 1 are replaced by the Zhanjiang mud snail seedlings in Comparative Example 2.

[0057] Comparative Example 5

[0058] The difference between this comparative example and Example 1 is that in step (3), pakchoi is not used for feeding.

[0059] Comparative Example 6

[0060] The difference between this comparative example and Example 1 is that in step (3), the common bait for Dongfeng snails, namely, balanga, is used for feeding.

[0061] Comparative Example 7

[0062] The difference between this comparative example and Example 3 is that the hybrid seedlings of Example 1 are replaced by the seedlings bred in Comparative Example 5.

[0063] Comparative Example 8

[0064] The difference between this comparative example and Example 3 is that the hybrid seedlings of Example 1 are replaced by the seedlings bred in Comparative Example 6.

[0065] Test Example 1

[0066] Samples were taken at two breeding stages in Examples 3-4, Comparative Examples 3-4 and Comparative Examples 7-8 to measure indicators. The test indicators were average body weight, average shell length and survival rate. The calculation method of the test indicators was as follows. The breeding results are shown in Table 1.

[0067] Average body weight = total weight of 200 snails / 200*100%.

[0068] Average shell length = total length of 200 shells / 200*100%.

[0069] Survival rate = number of snails harvested / number of seedlings released*100%.

[0070] Table 1

[0071] Group Example 3 Example 4 Comparative Example 3 Comparative Example 4 Comparative Example 7 Comparative Example 8 Average body weight in the first stage / g 0.35 0.33 0.24 0.17 0.30 0.28 Average shell length in the first stage / mm 1.25 1.24 0.94 1.01 1.13 1.06 Stage 1 survival rate % 88.7 87.9 70.4 75.4 83.4 82.5 Average body weight in the second phase / g 8.19 8.12 6.65 6.94 7.82 7.63 Average shell length in the second stage / mm 36.6 36.2 30.3 30.8 33.3 32.1 Stage II survival rate % 86.3 86.0 77.5 72.2 81.8 80.4

[0072] As can be seen from Table 1, by comparing the growth indicators of the three species of Babylonia snails in the two breeding stages, it can be found that the average weight, average shell height and survival rate of the hybrid seedlings are significantly higher than those of the common Taiwan Babylonia snail and Zhanjiang mud Babylonia snail.

[0073] Test Example 2

[0074] Sampling was performed to measure indices at the seedling raising stage in Examples 1-2, Comparative Examples 1-2 and Comparative Examples 5-6.

[0075] The fertilization rate and hatching rate of the above hybridization, as well as the metamorphosis rate of the planktonic larvae after culture, were calculated as follows, and the specific test results are shown in Table 2.

[0076] The fertilization rate is the average of 10 randomly selected egg capsules. The hatching rate is the average of the number of larvae counted by randomly slugging 500 ml of water with a measuring cylinder three times in each pond. The metamorphosis rate is the ratio of the number of successfully metamorphosed juvenile snails to the number of hatched larvae. The calculation formulas for the fertilization rate, hatching rate and metamorphosis rate are as follows. The breeding results are shown in Table 2 below.

[0077] Fertilization rate = number of fertilized eggs / (number of fertilized eggs + number of unfertilized eggs)*100%.

[0078] Hatching rate = number of hatched larvae / number of fertilized eggs*100%.

[0079] Metamorphosis rate = number of metamorphosed juvenile snails / number of hatched larvae*100%.

[0080] Table 2

[0081] Characteristics Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 5 Comparative Example 6 Fertilization rate% 94.1 92.7 66.7 75.2 85.5 81.3 Hatching rate% 92.3 95.4 73.3 76.8 79.9 78.1 Abnormality rate% 85.9 87.5 48.1 52.6 77.0 74.2

[0082] As shown in Table 2, compared with the existing Taiwan baby snails and mud baby snails, the hybrid baby snails have a better metamorphosis rate, and the fertilization rate and hatching rate are also significantly improved. The fertilization rate of baby snails is at least 39% and 23% higher than that of the two existing baby snails, respectively; the hatching rate is at least 30% and 24% higher; and the metamorphosis rate is at least 82% and 66% higher.

[0083] The foregoing examples are merely illustrative and are used to explain some features of the method of the present invention. The appended claims are intended to require the widest possible range that can be imagined, and the embodiments presented herein are demonstrated by the applicant's actual test results. Therefore, the applicant's intention is that the appended claims are not limited by the selection of examples that illustrate the features of the present invention. Some numerical ranges used in the claims also include sub-ranges therein, and changes in these ranges should also be interpreted as being covered by the appended claims where possible.

Claims

1. A method for breeding hybrid seedlings of Babylonia Taiwana and Babylonia Muscicapidae, characterized in that: The following steps are involved: S1. Enhanced cultivation of parent snails: Taiwan Babylonia parent snails and mud Babylonia parent snails are mixed and cultured in the dark, and are fed with vegetables accounting for 3-5% of the body weight of the Babylonia parent snails, and mixed biological bait accounting for 10-15% of the body weight of the Babylonia parent snails, and are continuously fed until the gonads mature, and are fed at least once a day; Taiwan Babylonia parent snails and mud Babylonia parent snails are hybridized to obtain egg capsule clusters; S2. Seedling cultivation: The egg capsule clusters hatch to form planktonic larvae. After 15 to 20 days of cultivation, the planktonic larvae metamorphose into juvenile snails, and hybrid seedlings are obtained; The mixed biological bait includes, by weight: 10 to 30 parts of clams, 40 to 50 parts of oysters, 5 to 15 parts of sandworms, and 10 to 30 parts of grain worms.

2. The breeding method according to claim 1, characterized in that: In step S1, the conditions for mixed farming are: ammonia nitrogen concentration ≤ 0.5 mg / L, nitrite concentration ≤ 0.1 mg / L, salinity 28-31, dissolved oxygen ≥ 5 mg / L, and calcium ion concentration ≥ 100 mg / L.

3. The breeding method according to claim 1, characterized in that: In step S2, the incubation conditions are: pH 8.3-8.6, dissolved oxygen 5-6 mg / L, water temperature 25-30° C., and seawater specific gravity 1.020-1.014 g / mL.

4. The breeding method according to claim 1, characterized in that: In step S1, the vegetables are selected from one or more of Chinese cabbage, cabbage, pumpkin, mustard greens, black cabbage, sedge, kale, shepherd's purse, spinach, amaranth, kale, and Chinese cabbage.

5. The breeding method according to claim 1, characterized in that: In the step S1, the mixed biological bait further contains lecithin powder.

6. The breeding method according to claim 1, characterized in that: In the step S1, the Taiwan baby snails and the mud baby snails are mixed and cultured in a male-female ratio of 1:1-2.

7. The breeding method according to claim 1, characterized in that: In step S2, the density of the egg cyst cluster hatching is 0.1-0.3 catties / m 3 .

8. The breeding method according to claim 1, characterized in that: In step S2, during the cultivation period, mixed algae are fed every 2 to 3 times; allicin is fed every 2 to 3 days, and vitamins are added every day.

9. The breeding method according to claim 1, characterized in that: In step S2, when the shell length of the planktonic larvae reaches about 1000 microns, shrimp flakes and yeast are added to the bait for feeding.

10. The breeding method according to any one of claims 1 to 9, characterized in that: The mud snail is the Zhanjiang mud snail.