Litopenaeus vannamei fast-growth character specialized strain construction method

Abstract

The invention discloses a method for constructing a dynamic specialized strain with a fast growth character of litopenaeus vannamei. The method comprises the following steps: collecting and cultivating a fast-growing population, screening the fast-growing population, three rounds of screening of individuals in the fast-growing population, zero-generation parent cultivation and F1-generation breeding, F1-generation cultivation and F2-generation breeding, F2-generation cultivation and F3-generation breeding, dynamic maintenance of a fast-growing character specialized strain and the like. The prawn strain breeding method does not need family construction, has the characteristics of simplicity, high efficiency and low cost, and lays a technical foundation for large-scale and wide development of prawn rapid growth character breeding.

Description

Technical Field

[0001] The invention belongs to the technical field of aquaculture, and in particular relates to a method for constructing a specialized strain of Penaeus vannamei with fast-growth traits. Background Art

[0002] Penaeus vannamei, also known as whiteleg shrimp, is the largest farmed shrimp species in my country and the world, and has become an important representative of the high-quality protein source for national consumption. Penaeus vannamei farming occupies a very important position in my country's aquaculture, and it is of great significance to promote employment. The seed industry is the "chip" of agriculture, and the Penaeus vannamei seed industry is crucial to supporting the sustainable development of the entire shrimp farming industry. However, on the whole, my country's Penaeus vannamei seed industry lacks technological innovation and weak research and development capabilities for new varieties. Therefore, the Penaeus vannamei seed industry has become one of the bottleneck problems that need to be urgently solved in my country's agricultural field.

[0003] At present, my country has 15 new varieties of Penaeus vannamei, but these new varieties are mainly obtained by the method of building families. In the process of breeding new varieties, a large number of families need to be built generation by generation. The construction of shrimp families, the selection of offspring families, and group mating require a lot of manpower and occupy a lot of breeding facility space, resulting in huge costs for the breeding of new shrimp varieties, which limits the enthusiasm of enterprises to participate in the breeding of new shrimp varieties. In addition, in order to avoid inbreeding, family transmission generally adopts the method of mating between different families. On the one hand, it makes the pedigree of the offspring gradually complicated, and on the other hand, it may also cause the loss of already homozygous traits and genotypes. Based on this, it is also necessary to explore low-cost and efficient breeding methods for new varieties of Penaeus vannamei.

[0004] In the production of commercial pigs and other livestock, it is usually necessary to select and breed specialized strains with outstanding traits, and then conduct strict compatibility tests to form special hybrid combinations to produce high-quality commercial pigs, so that commercial pigs can concentrate the advantages of various strains and have more obvious hybrid advantages. Shrimp belongs to lower invertebrates and has obvious characteristics different from livestock in reproductive biology. Specifically, (1) Shrimp can only produce for one breeding season, while excellent breeding stock of livestock such as pigs can produce for many consecutive years; (2) Shrimp population reproduction follows the R strategy, where a single adult can produce millions of offspring, but only a few offspring have the opportunity to reproduce in the natural environment, while livestock and other higher animal population reproduction follows the K strategy, where a single adult can only produce a few high-quality offspring and maintain population reproduction with a low mortality rate. The above two characteristics determine that the specialized strain breeding method of livestock such as pigs is not suitable for the specialized strain breeding of shrimp. Therefore, it is necessary to develop a unique specialized strain breeding method based on the biological characteristics and breeding trait requirements of shrimp. Summary of the invention

[0005] The purpose of the present invention is to provide a method for constructing a dynamic specialized strain of fast-growing traits of Penaeus vannamei without the need for family construction, which is simple, efficient and low-cost, and lays a technical foundation for large-scale and extensive breeding of fast-growing traits of shrimp.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] A method for constructing a fast-growing trait specialized strain of Penaeus vannamei comprises the following steps:

[0008] (1) Collection and cultivation of fast-growing groups: 10,000 to 20,000 shrimp fry (P6 to P10) of each fast-growing group of Penaeus vannamei from 40 to 60 different sources were collected and cultivated in the same specification seed storage pond in the seed storage workshop for 30 days;

[0009] (2) Screening of fast-growing groups: 100 fish are randomly selected from the above 40 to 60 groups and weighed. The average weight is used to represent the growth rate of the group. The 40 to 60 groups are sorted according to growth rate. The top 20 to 30 fast-growing groups are selected, and the rest are eliminated;

[0010] (3) The first round of screening of individuals in the fast-growing groups: 400 shrimps with the largest weight are selected from each of the 20 to 30 fast-growing groups retained above and continue to be cultivated in the seed storage pond;

[0011] (4) Second round of screening of individuals in the fast-growing group: After the shrimp in the above fast-growing group are cultured for 60 days, a second round of screening is carried out, and 200 shrimps with the largest weight and healthy appearance are selected from each group and continue to be cultured in the breeding tank;

[0012] (5) The third round of screening of individuals in the fast-growing group: After the shrimps in the above fast-growing group are cultured for 90 days, the third round of screening is carried out. The 100 shrimps with the largest weight and healthy appearance are selected from each group. A total of 2,000 to 3,000 shrimps are mixed as the basic group and continue to be cultured in the parent culture pond;

[0013] (6) Breeding of zero-generation parents and F1 generation breeding: After the above-mentioned 2,000 to 3,000 fast-growing shrimps are cultured to 10 to 12 months of age, the males and females are separated and cultured in parent ponds at a rate of 400 to 600 per pond, and conventional parent ripening operations and management are performed; the mature female shrimps are promptly removed and placed in male shrimp ponds for natural mating; after mating, the female shrimps are removed and placed in spawning barrels for conventional spawning and hatching operations; all offspring of the same batch of spawning female shrimps are collected in the same nursery pond for conventional shrimp nursery operations, thereby producing F1 generation closed group shrimp fry with fast-growing traits;

[0014] (7) F1 generation cultivation and F2 generation breeding: 16,000 to 24,000 shrimp F1 generation closed group seedlings with fast growth traits (P6 to P10) are taken, and the cultivation is continued for 30 days. The shrimps are filtered and screened using a sieve, and 8,000 to 12,000 shrimps intercepted by the sieve are retained; the cultivation is continued for 60 days, and 4,000 to 6,000 shrimps with large size and healthy appearance are selected; the cultivation is continued for 90 days, and 2,000 to 3,000 shrimps with large size and healthy appearance are selected, and the F1 generation parents are cultivated according to the method in the above step (6), and the F2 generation is bred according to the method in the above step (6);

[0015] (8) F2 generation cultivation and F3 generation breeding: 16,000 to 24,000 F2 generation closed group shrimp fry (P6 to P10) with fast growth traits are taken, and the cultivation is continued for 30 days. The shrimp fry are filtered and screened using a sieve, and 8,000 to 12,000 shrimp individuals retained by the sieve are retained; the cultivation is continued for 60 days, and 4,000 to 6,000 large-sized and healthy-looking individuals are selected; the cultivation is continued for 90 days, and 2,000 to 3,000 large-sized and healthy-looking individuals are selected, and the F2 generation parent cultivation is carried out according to the method in the above step (6), and the F3 generation breeding is carried out according to the method in the above step (6). The F3 generation is the obtained specialized strain of Penaeus vannamei with fast growth traits;

[0016] (9) Dynamic maintenance of specialized strains with fast-growing traits: Starting from the F3 generation, 8 to 12 populations of fast-growing shrimp from different sources are reconstructed according to the methods of steps (1) to (5) above. Twenty-five fast-growing shrimp individuals are selected from each population, totaling 200 to 300 shrimp individuals. These are cultured to the parents and supplemented to the specialized strains containing 1,800 to 2,700 shrimp parents. Conventional breeding operations are then performed. Thereafter, this step is repeated once every two generations to complete the dynamic maintenance of specialized strains with fast-growing traits.

[0017] In step (5), the weight of the basic group of shrimps is ≥15 g.

[0018] In step (6), the weight of the fast-growing shrimp when the males and females are separated is ≥ 40 g.

[0019] In steps (7) and (8), the pore size of the sieve is 8 mm.

[0020] The present invention also provides the application of the construction method in the breeding of Penaeus vannamei, wherein the breeding is to construct a specialized strain of Penaeus vannamei with fast growth traits.

[0021] Compared with the traditional pedigree construction method, the method for constructing a specialized strain of fast-growing shrimp of the present invention has the following advantages and positive effects:

[0022] (1) The process of constructing a specialized strain of fast-growing shrimp according to the present invention does not require any pedigree construction operation, thereby greatly reducing labor intensity and saving a large amount of manpower and cultivation facility space, thereby making the breeding of shrimp simple and easy, and laying a technical foundation for large-scale and extensive breeding of fast-growing shrimp.

[0023] (2) In the past, in order to avoid inbreeding, it was necessary to establish families from different sources and perform complex inter-family mating operations and pedigree records. In the present invention, since fast-growing individuals from 20 to 30 shrimp groups from different sources that have been strictly screened are mixed in equal proportions, the maximum probability of inbreeding is theoretically only 1.25 to 2.5%. Even if there are bad offspring from inbreeding, they will be eliminated in the three rounds of screening of individuals in the fast-growing group due to their inferior traits.

[0024] (3) Due to the limitation of cost and facility space, the number of source parental individuals in each generation of a family is very limited, which will lead to a decrease in the genetic diversity of the offspring. In the present invention, the source of parents in each generation is very wide, and while the traits are gradually purified and the genotypes associated with the traits are gradually homozygous, a high genetic diversity is maintained.

[0025] (4) Starting from the F3 generation, new fast-growing trait groups are reintroduced every two generations to keep specialized strains relatively open and dynamically updated, increase genetic diversity, and reduce the occurrence of genetic decline. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a technical route for constructing dynamic specialized strains of fast-growing traits of Penaeus vannamei. DETAILED DESCRIPTION

[0027] The following examples are provided to further illustrate the present invention, rather than to limit the present invention.

[0028] Example 1

[0029] From 2020 to 2024, the construction and dynamic maintenance of the fast-growing specialized strain FG-1 of Penaeus vannamei will be carried out in the following manner.

[0030] (1) Collection and cultivation of fast-growing groups: In May 2020, 15,000 shrimp fry (P8) of each fast-growing group of Penaeus vannamei from 50 different sources were collected and cultivated in seed preservation ponds of the same specifications in the seed preservation workshop for 30 days.

[0031] (2) Screening of fast-growing groups: 100 fish were randomly selected from the above 50 groups and weighed. The average weight was used to represent the growth rate of the group. The 50 groups were sorted according to growth rate. The top 25 fast-growing groups were retained and the rest were eliminated.

[0032] (3) The first round of screening of individuals in the fast-growing groups: From the 25 fast-growing groups retained above, select the 400 largest shrimps from each group and continue to cultivate them in the seed storage pond.

[0033] (4) Second round of screening of individuals in the fast-growing group: After the shrimp in the above fast-growing group are cultured for 60 days, a second round of screening is carried out. The 200 shrimp with the largest weight and healthy appearance are selected from each group and continue to be cultured in the breeding tank.

[0034] (5) The third round of screening of individuals in the fast-growing group: After the shrimp in the above fast-growing group are cultivated for 90 days, the third round of screening is carried out. The 100 shrimps with the largest weight and healthy appearance are selected from each group. A total of 2,500 shrimps (weight ≥ 15 g) are mixed as the basic group (zero generation) and continue to be cultivated in the parent breeding pond.

[0035] (6) Zero-generation parent cultivation and F1 generation breeding: After the above-mentioned 2,500 fast-growing shrimps are cultivated to 11 months of age (weight ≥ 40g), the males and females are separated and 500 males / pond are cultured in parent ponds respectively, and routine parent ripening operations and management are carried out. In April 2021, the mature female shrimps will be removed in time and placed in the male shrimp pond for natural mating. After mating, the female shrimps will be removed and placed in the spawning bucket for routine spawning and hatching operations. All offspring of the same batch of spawning female shrimps are collected in the same nursery pond for routine shrimp nursery operations to produce F1 generation closed group shrimp fry with fast-growing traits.

[0036] (7) F1 generation cultivation and F2 generation breeding: In May 2021, 20,000 F1 generation closed group shrimp seedlings with fast growth traits (P8) were taken; continued cultivation for 30 days, filtered and screened with a sieve with a pore size of 8 mm, and 10,000 shrimp individuals intercepted by the sieve were retained, and continued cultivation for 60 days, and 5,000 large-sized and healthy-looking individuals were selected; continued cultivation for 90 days, and 2,500 large-sized and healthy-looking individuals were selected, and F1 generation parent cultivation was carried out according to the method in the above step (6). In April 2022, F2 generation breeding was carried out according to the method in the above step (6).

[0037] (8) F2 generation cultivation and F3 generation breeding: In May 2022, 20,000 F2 generation closed group shrimp seedlings with fast growth traits (P8) were taken; continued cultivation for 30 days, filtered and screened with a sieve with a pore size of 8 mm, and 10,000 shrimp individuals retained by the sieve were retained; continued cultivation for 60 days, and 5,000 large-sized and healthy-looking individuals were selected; continued cultivation for 90 days, and 2,500 large-sized and healthy-looking individuals were selected, and F2 generation parent cultivation was carried out according to the method in the above step (6). In April 2023, the F3 generation was bred according to the breeding method in the above step (6), and the F3 generation obtained the specialized strain FG-1 of Penaeus vannamei with fast growth traits.

[0038] (9) Dynamic maintenance of specialized strains with fast growth traits: In May 2023, starting from the F3 generation, 10 populations of fast-growing shrimp from different sources were reconstructed according to the methods of steps (1) to (5) above. 25 fast-growing shrimp individuals were selected from each population (a total of 250 shrimp individuals) and cultivated to the parents. In April 2024, they were added to the specialized strain FG-1 containing 2250 shrimp parents, and then conventional breeding operations were carried out to complete the dynamic maintenance of the specialized strain FG-1 with fast growth traits.

[0039] Example 2

[0040] From 2021 to 2024, the fast-growth specialized strain FG-2 of Penaeus vannamei will be constructed in the following manner.

[0041] (1) Collection and cultivation of fast-growing groups: In May 2021, 20,000 shrimp fry (P10) of each fast-growing group of Penaeus vannamei from 60 different sources were collected and cultivated in seed preservation ponds of the same specifications in the seed preservation workshop for 30 days.

[0042] (2) Screening of fast-growing groups: 100 fish were randomly selected from the above 60 groups and weighed. The average weight was used to represent the growth rate. The 60 groups were sorted according to growth rate. The top 30 fast-growing groups were retained and the rest were eliminated.

[0043] (3) The first round of screening of individuals in the fast-growing groups: From the 30 fast-growing groups retained above, select the 400 largest shrimps from each group and continue to cultivate them in the seed storage pond.

[0044] (4) Second round of screening of individuals in the fast-growing group: After the shrimp in the above fast-growing group are cultured for 60 days, a second round of screening is carried out. The 200 shrimp with the largest weight and healthy appearance are selected from each group and continue to be cultured in the breeding tank.

[0045] (5) The third round of screening of individuals in the fast-growing group: After the shrimp in the above fast-growing group are cultivated for 90 days, the third round of screening is carried out. The 100 shrimps with the largest weight and healthy appearance (weight ≥ 15g) are selected from each group. A total of 3,000 shrimps are mixed as the basic group (zero generation) and continue to be cultivated in the parent breeding pond.

[0046] (6) Zero-generation parent cultivation and F1 generation breeding: After the above 3,000 fast-growing shrimps are cultivated to 11 months of age (weight ≥ 40g), the males and females are separated and 500 males / pond are cultured in parent ponds respectively, and routine parent ripening operations and management are carried out. In April 2022, the mature female shrimps will be removed in time and placed in the male shrimp pond for natural mating. After mating, the female shrimps will be removed and placed in the spawning bucket for routine spawning and hatching operations. All offspring of the same batch of spawning female shrimps are collected in the same nursery pond for routine shrimp nursery operations to produce F1 generation closed group shrimp fry with fast-growing traits.

[0047] (7) F1 generation cultivation and F2 generation breeding: In May 2022, 24,000 F1 generation closed group shrimp seedlings with fast growth traits (P10) were obtained; the cultivation was continued for 30 days, and the shrimp were filtered and screened using a sieve with a pore size of 8 mm, and 12,000 shrimp individuals intercepted by the sieve were retained, and the cultivation was continued for 60 days, and 6,000 large-sized and healthy-looking individuals were selected; the cultivation was continued for 90 days, and 3,000 large-sized and healthy-looking individuals were selected, and the F1 generation parent cultivation was carried out according to the method in the above step (6). In April 2023, the F2 generation was bred according to the method in the above step (6).

[0048] (8) F2 generation cultivation and F3 generation breeding: In May 2023, 24,000 F2 generation closed group shrimp seedlings with fast growth traits (P10) were taken; continued cultivation for 30 days, filtered and screened with a sieve with a pore size of 8 mm, and 12,000 shrimp individuals retained by the sieve were retained; continued cultivation for 60 days, and 6,000 large-sized and healthy-looking individuals were selected; continued cultivation for 90 days, and 3,000 large-sized and healthy-looking individuals were selected, and F2 generation parent cultivation was carried out according to the method in the above step (6). In April 2024, the F3 generation was bred according to the breeding method in the above step (6), and the F3 generation obtained the specialized strain FG-2 of Penaeus vannamei with fast growth traits.

[0049] Example 3

[0050] Comparison of growth traits between the specialized strain FG-2 and the common strain of Penaeus vannamei.

[0051] In May 2024, the growth rate of the fast-growing specialized strain FG-2 and the HQ fast-growing shrimp seedlings purchased from the market were compared. 200 shrimp seedlings of the FG-2 strain and HQ strain (both with a body length of 0.8-1 cm) were taken, and both were cultured in a breeding barrel containing 600L of seawater. The breeding cycle was 60 days, and both were subjected to normal breeding management. After 60 days, 50 shrimps were randomly taken from each strain for weight weighing. The statistical results are shown in Table 1.

[0052] Table 1 Comparison of growth rates of fast-growing specialized strain FG-2 and conventional HQ fast-growing varieties (60 days, n=50)

[0053]

[0054] As can be seen from Table 1, after 60 days of breeding, the average body weight of the fast-growing specialized strain FG-2 reached 11.0g, and the average daily weight gain reached 183.3mg / d. The growth rate was 11.1% higher than that of the control HQ fast-growing variety, reflecting the growth rate advantage of the fast-growing specialized strain FG-2.

[0055] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for constructing a fast-growing trait specialized strain of Penaeus vannamei, characterized in that: The following steps are involved: (1) Collection and cultivation of fast-growing groups: 10,000 to 20,000 shrimp fry of each fast-growing group of Penaeus vannamei from 40 to 60 different sources were collected and cultivated in the same specification seed storage pond in the seed storage workshop for 30 days; (2) Screening of fast-growing groups: 100 fish are randomly selected from the above 40 to 60 groups and weighed. The average weight is used to represent the growth rate of the group. The 40 to 60 groups are sorted according to growth rate. The top 20 to 30 fast-growing groups are selected, and the rest are eliminated; (3) The first round of screening of individuals in the fast-growing population: 400 of the largest shrimps are selected from the 20 to 30 fast-growing populations retained above and continue to be cultivated in the seed storage pond; (4) Second round of screening of individuals in the fast-growing group: After the shrimp in the above fast-growing group are cultured for 60 days, a second round of screening is carried out, and 200 shrimps with the largest weight and healthy appearance are selected from each group and continue to be cultured in the breeding tank; (5) The third round of screening of individuals in the fast-growing group: After the shrimps in the above fast-growing group are cultured for 90 days, the third round of screening is carried out. The 100 shrimps with the largest weight and healthy appearance are selected from each group. A total of 2,000 to 3,000 shrimps are mixed as the basic group and continue to be cultured in the parent culture pond; (6) Breeding of zero-generation parents and F1 generation breeding: After the above-mentioned 2,000 to 3,000 fast-growing shrimps are cultured to 10 to 12 months of age, the males and females are separated and cultured in parent ponds at a rate of 400 to 600 per pond, and conventional parent ripening operations and management are performed; the mature female shrimps are promptly removed and placed in male shrimp ponds for natural mating; after mating, the female shrimps are removed and placed in spawning barrels for conventional spawning and hatching operations; all offspring of the same batch of spawning female shrimps are collected in the same nursery pond for conventional shrimp nursery operations, thereby producing F1 generation closed group shrimp fry with fast-growing traits; (7) F1 generation cultivation and F2 generation breeding: 16,000 to 24,000 F1 generation closed group shrimp seedlings with fast growth traits are taken, and the cultivation is continued for 30 days. The shrimps are filtered and screened using a sieve, and 8,000 to 12,000 shrimps intercepted by the sieve are retained; the cultivation is continued for 60 days, and 4,000 to 6,000 shrimps with large size and healthy appearance are selected; the cultivation is continued for 90 days, and 2,000 to 3,000 shrimps with large size and healthy appearance are selected, and the F1 generation parents are cultivated according to the method in the above step (6), and the F2 generation is bred according to the method in the above step (6); (8) F2 generation cultivation and F3 generation breeding: 16,000 to 24,000 F2 generation closed group shrimp fry with fast growth traits are taken, and the cultivation is continued for 30 days. The shrimp fry are filtered and screened by a sieve, and 8,000 to 12,000 shrimp individuals intercepted by the sieve are retained; the cultivation is continued for 60 days, and 4,000 to 6,000 large-sized and healthy-looking individuals are selected; the cultivation is continued for 90 days, and 2,000 to 3,000 large-sized and healthy-looking individuals are selected, and the F2 generation parents are cultivated according to the method in the above step (6), and the F3 generation is bred according to the method in the above step (6). The F3 generation is the obtained specialized strain of Penaeus vannamei with fast growth traits; (9) Dynamic maintenance of specialized strains with fast-growing traits: Starting from the F3 generation, 8 to 12 populations of fast-growing shrimp from different sources are reconstructed according to the methods of steps (1) to (5) above. Twenty-five fast-growing shrimp individuals are selected from each population, totaling 200 to 300 shrimp individuals. These are cultured to the parents and supplemented to the specialized strains containing 1,800 to 2,700 shrimp parents. Conventional breeding operations are then performed. Thereafter, this step is repeated once every two generations to complete the dynamic maintenance of specialized strains with fast-growing traits.

2. The method for constructing a fast-growing trait specialized strain of Penaeus vannamei according to claim 1, characterized in that: In step (5), the weight of the basic group of shrimps is ≥15 g.

3. The method for constructing a specialized strain of Penaeus vannamei fast-growth traits according to claim 1, characterized in that: In step (6), the weight of the fast-growing shrimp when the males and females are separated is ≥ 40 g.

4. The method for constructing a fast-growing trait specialized strain of Penaeus vannamei according to claim 1, characterized in that: In steps (7) and (8), the pore size of the sieve is 8 mm.

5. Application of the construction method according to any one of claims 1 to 4 in breeding of Penaeus vannamei.

6. The use according to claim 5, characterized in that: The breeding is to construct a specialized strain of Penaeus vannamei with fast growth traits.

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