Family breeding method of blue crab fast-growing strain

Abstract

The invention discloses a family breeding method of blue crab fast-growing strains, which is characterized by comprising the following steps: collecting full-cream crabs from different geographical areas, disinfecting, then adopting a series of measures to promote egg carrying, carrying out multi-stage intensified screening and breeding in different environments after membrane rupture of the eggs, and finally breeding the blue crab fast-growing strains. And calculating indexes such as a good rate, a weight growth rate and a body type growth rate, and setting a weight to determine a comprehensive score so as to select a good family. Constructing a family pairing scheme, separately breeding male and female, mating at a specific time, marking and continuing to breed seedlings. And repeating the breeding process of multiple generations. The method ensures genetic diversity, scientific breeding screening, quantitative evaluation index, targeted pairing and sustainable improvement of the blue crab variety, and provides an efficient breeding approach for the blue crab breeding industry.

Description

Technical Field

[0001] The invention relates to the technical field of blue crab breeding, and more specifically to a family breeding method for blue crab fast-growing strains. Background Art

[0002] Blue crabs are large in size, grow fast, and have delicious meat. They are an excellent marine aquaculture crab. Blue crab farming has the advantages of low investment, quick results, good benefits, and convenient technical management. It has become an emerging marine industry in southern my country. At present, most of the seedlings required for blue crab farming come from wild seedlings and have not yet been genetically improved. During the breeding process, it has been found that the blue crab's resistance to stress, disease resistance, and growth rate have decreased, and the uniformity of product specifications is poor. By breeding new varieties of fast-growing and stress-resistant blue crabs, the impact of diseases and environmental deterioration on blue crab farming can be reduced.

[0003] As an important means of variety improvement, family selection has played a very good role in the variety improvement of aquatic animals. Among them, the family selection work of fish and shrimp has been continuously carried out, and good results have been obtained successively. At present, there are still few family selection methods for blue crabs, and the efficiency of selection is also average. It is difficult to obtain excellent families for a long time, and the investment cost is high but the effect is slow. Therefore, the inventor proposes this application to provide a blue crab family selection method with high efficiency. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a family breeding method for fast-growing strains of blue crabs, which has the advantage of high breeding efficiency and can effectively select excellent families to obtain excellent blue crab varieties.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for family breeding of fast-growing blue crab strains, comprising the following steps:

[0006] 1) Collecting crabs with full roe from different geographical areas, sterilizing and removing diseases from the crabs, and then placing them in a cultivation pond for culture until the end of the egg-carrying stage;

[0007] 2) The crabs with eggs are moved to a barrel for laying. After the eggs break the membrane, the crab seedlings are collected and cultivated to the fifth stage of crab larvae. Then, each family is subjected to an intensive screening with an intensity of 20%. After the screening, the crab seedlings of different families are further cultivated in different earth pits or large pond enclosures;

[0008] 3) After the crabs are grown, the male and female crabs are distinguished and further intensively screened at an intensity of 20% and the breeding is continued;

[0009] 4) Different fluorescent markers are marked on the plastron according to different families. After marking, the blue crabs of different families are cultured in a large pond until they molt, and then an enhanced screening with an intensity of 20% is performed again;

[0010] 5) Counting and ranking the families of the remaining blue crabs after the enhanced screening to obtain the excellent families to be selected;

[0011] 6) Count the number of blue crabs in each family among the selected excellent families and calculate the excellent rate P of the family A , count the weight and length of all blue crabs, calculate the overall average weight and average size, and at the same time count the average weight and average size of blue crabs in each family of the selected excellent families, and calculate the weight growth rate M of the family A and body growth rate C A ;

[0012] 7) Set different weights for the excellent rate, weight growth rate, and body shape growth rate, and calculate the comprehensive score E for each family A , sorted by comprehensive scores, and finally obtained excellent pedigrees;

[0013] 8) Construct a family pairing plan, separate male and female crabs from the same family, and when the female crab is about to molt, select male crabs from the corresponding family and place them in a bucket and shade them from the sun. After the female crab molts, the male crabs will mate autonomously. After mating, wait for the female crab shell to harden and collect it back. After confirming that mating is complete, one crab is cultivated in a single frame with one code, and the subsequent seedling breeding work is continued;

[0014] 9) Repeat steps 2) to 8) to carry out family breeding for multiple generations.

[0015] The present invention is further configured as follows: when calculating the good and good rate, the total number of remaining blue crabs after screening is recorded as S 总 , the number of blue crabs in the corresponding family is S A , then the superiority rate of the blue crab of this family

[0016] The present invention is further configured as follows: when calculating the weight growth rate, the average weight of the whole blue crab is recorded as W 总 , the average weight of the blue crabs in the corresponding family is recorded as W A , then the weight growth rate of the blue crab of this family is

[0017]

[0018] The present invention is further configured as follows: when calculating the body growth rate, the average body size of the entire blue crab is recorded as B 总 The average size of the blue crabs in the corresponding family is recorded as B A , then the body growth rate of the blue crab of this family is

[0019] The present invention is further configured as follows: when calculating the comprehensive score, the weight of the good rate is ω1, the weight of the weight growth rate is ω2, the weight of the body shape growth rate is ω3, and ω1+ω2+ω3=1, the family comprehensive score E A=(ω1P A +ω2M A +ω3C A )×100, where 100 is the adjustment coefficient.

[0020] The present invention is further configured as follows: the weights ω1=0.5; ω2=0.3; ω3=0.2.

[0021] The present invention is further configured as follows: in the step 1), the unilateral eye stalk of the crab is cut off, the temperature and salt level of the culture pond are increased, and the nutrition is enhanced, and the culture pond is cleaned and dried for 30-40 minutes every morning to promote the crab to incubate eggs at the same time.

[0022] The present invention is further configured as follows: the enhanced screening with an intensity of 20% is to determine the growth rate and sort it according to the body weight, and retain the top 20% in the sort.

[0023] The present invention is further configured as follows: in the step 8), pairing is performed in a female-to-male ratio of 2:1 to cultivate half-baby families and full-baby families.

[0024] In summary, the present invention has the following beneficial effects:

[0025] The present invention screens out blue crab families with excellent growth performance through multiple intensive screenings, thereby improving the accuracy and efficiency of breeding; at the same time, all families are screened together during the last intensive screening, which has the advantage of directly excluding poor families during screening, thereby improving the efficiency of family breeding. Furthermore, by counting the excellent families to be selected, and calculating the comprehensive score in combination with the excellent rate, weight growth rate and body growth rate, the final excellent families thus obtained greatly improve the accuracy and efficiency. Compared with the traditional breeding method, the present invention divides families into intensive screenings in advance, and the last integrated screening can directly exclude poor families, which can reduce the number of statistics required in the later stage and improve the breeding efficiency; and the obtained excellent families to be selected are combined with the calculation to obtain the final excellent families, which can improve the accuracy of breeding. DETAILED DESCRIPTION

[0026] The present invention is described in further detail below.

[0027] This embodiment discloses a method for family breeding of a fast-growing strain of blue crab, comprising the following steps:

[0028] 1) Collect crabs with full roe from different geographical areas, disinfect and remove diseases from the crabs, and then place them in the cultivation pond for breeding until the end of the egg-holding stage; collect parents from different blue crab breeding areas to increase the genetic diversity of blue crabs, obtain excellent genes as much as possible, and provide a richer genetic basis for subsequent breeding. Choose healthy, non-disabled crabs with full roe, no barnacles or other attachments on the crab shell surface, preferably weighing 400-750 grams, and use 10-20ppm potassium permanganate or 100-150ppm formaldehyde solution for disinfection, soak the crabs for 20-30 minutes, and then soak the crabs in sodium thiosulfate or vitamin C solution for detoxification to remove the diseases they carry.

[0029] 2) Move the egg-carrying crabs to the spawning bucket. After the eggs break the membrane, collect the crab seedlings and cultivate them to the fifth stage of crab larvae. Then each family is subjected to intensive screening with an intensity of 20%. After screening, crab seedlings of different families are further cultivated in different large pond enclosures; preliminarily select crab seedlings with better growth performance to improve the efficiency and quality of subsequent breeding. At the same time, the large pond enclosure method is used to provide independent growth space for different families.

[0030] 3) After the crabs are bred to the point of buckling, male and female crabs are distinguished and then subjected to 20% intensive screening respectively, and the breeding is continued; at this time, the growth characteristics of male and female crabs are different, and male crabs generally grow faster, so it is necessary to distinguish male and female crabs for screening to ensure a balance in the number of male and female crabs.

[0031] 4) Different fluorescent markers are marked on the plastron according to different families. After marking, the blue crabs of different families are integrated and cultured in a large pond until before reproductive molting, and then an enhanced screening with an intensity of 20% is carried out again; marking is convenient for distinguishing blue crabs of different families, and then they are integrated for screening. During the process, if there are poor families that are all in the exclusion 80%, they can be directly excluded, reducing the subsequent workload, improving efficiency, and effectively and quickly determining the families with better performance.

[0032] 5) Count the families of the remaining blue crabs after the enhanced screening and sort them to obtain the excellent families to be selected; this step counts the families of the remaining blue crab fast-growing strains, especially after the families are integrated and 20% are enhanced. The number of blue crabs belonging to each family is different. For example, family 1 has 10, family 2 has 15, and family 3 may be completely removed by enhanced screening. Therefore, this method can directly screen out 20% of the excellent blue crabs in all families, and can quickly determine the families with better performance, providing key focus for subsequent in-depth analysis and breeding. However, the families at this time are not accurate. Even the families with the largest number do not represent the fastest growth rate, but only represent that their gene expression is more stable. Therefore, the families need to be further optimized.

[0033] 6) Count the number of blue crabs in each family among the selected excellent families and calculate the excellent rate P of the family A, count the weight and length of all blue crabs, calculate the overall average weight and average size, and at the same time count the average weight and average size of blue crabs in each family of the selected excellent families, and calculate the weight growth rate M of the family A and body growth rate C A ; Through this step, among the excellent families to be selected, multiple indicators are used to comprehensively evaluate the advantages and disadvantages of the families, avoiding the limitations of a single indicator and providing a scientific basis for comprehensive evaluation. At the same time, the above indicators can also be flexibly adjusted to select more different indicators, such as the survival rate and disease resistance rate in the family. The survival rate of each family should be the number of blue crabs that died during steps 2) to 4) to obtain the mortality rate, and the survival rate = 1-mortality rate. The disease incidence rate should also be the number of blue crabs that developed diseases during steps 2) to 4) to obtain the disease incidence rate, and the disease resistance rate = 1-disease incidence rate; It should be noted that the subsequent comprehensive score of this method is calculated in a plus-point manner, so all indicators should be positive indicators.

[0034] 7) Set different weights for indicators such as excellent rate, weight growth rate, and body shape growth rate, and calculate the comprehensive score E of each family A , sort by comprehensive scores, and get the final excellent families; in this step, the importance of different indicators can be reasonably weighed according to the focus of breeding goals, and families with excellent comprehensive performance can be accurately selected. When a family with a high excellent rate is needed, its weight is increased. When a family with a fast growth rate is needed, a higher weight is given to the weight growth rate, and the body growth rate indicates that the body size of the family is relatively larger. If you want to obtain better commodity attributes on the market, you need to increase this weight. It should be noted that the body growth rate can not only be viewed independently, but also relatively, that is, when the weight of all blue crabs is the same, the weight needs to be increased.

[0035] 8) Construct a family pairing plan, in which male and female crabs of the same family are cultured separately. Before the female crab is about to molt, the female crab and the male crab of the corresponding family are placed in a bucket and shaded to provide a suitable environment. After the female crab molts, the male crab mates autonomously. After mating is completed, the female crab is collected after its shell hardens. After mating is confirmed, one crab is cultured in a single frame with one code, and subsequent seedling breeding work is continued; that is, the mated female crab is continued to be cultured until it carries eggs and obtains offspring.

[0036] 9) Repeat steps 2) to 8) to collect statistics on the offspring traits to test whether the growth traits have been improved. At the same time, carry out multi-generation family breeding to continuously accumulate genes for excellent traits and gradually optimize the blue crab variety.

[0037] Furthermore, when calculating the good and excellent rate, the specific calculation method is that the total number of remaining blue crabs after screening is recorded as S 总 , the number of blue crabs in the corresponding family is SA , then the superiority rate of the blue crab of this family When calculating the weight growth rate, the average weight of the whole crab is recorded as W 总 , the average weight of the blue crabs in the corresponding family is recorded as W A , then the weight growth rate of the blue crab of this family is When calculating the body growth rate, the average body size of the entire blue crab is recorded as B 总 The average size of the blue crabs in the corresponding family is recorded as B A , then the body growth rate of the blue crab of this family is The above content clarifies the specific calculation methods for the quality rate, weight growth rate and body shape growth rate, provides a quantitative evaluation standard for the breeding process, and makes breeding more scientific and accurate.

[0038] Furthermore, when calculating the comprehensive score, the weight of the good rate is ω1, the weight of the weight growth rate is ω2, the weight of the body shape growth rate is ω3, and ω1+ω2+ω3=1, the family comprehensive score E A =(ω1P A +ω2M A +ω3C A )×100, where 100 is the adjustment coefficient, which is used to amplify the score and make it easier to count the data, and it has no practical meaning. In this embodiment, the following weights are set based on experience: ω1=0.5; ω2=0.3; ω3=0.2. In the actual breeding process, the weights can be flexibly adjusted. The weights in this embodiment are intended to comprehensively consider the growth rate and the quality rate, and obtain a family with stable overall trait performance and a good growth rate. In the actual breeding process, the importance of different traits in breeding can be adjusted according to actual needs, so as to more specifically select excellent families that meet the goals.

[0039] Furthermore, in the step 1), the unilateral eye stalk of the crab is cut off, the temperature and salinity of the culture pond are increased, and the nutrition is fortified. The water in the culture pond is changed and cleaned every morning and the culture pond is dried for 30-40 minutes. The measures taken for the crab include cutting off the unilateral eye stalk, increasing the temperature and salinity of the culture pond, fortifying the nutrition, changing the water, cleaning and drying every day, which can effectively promote the crab to carry eggs at the same time, improve the number and quality of the crabs carrying eggs, and provide a sufficient source of crab seedlings for subsequent breeding.

[0040] Furthermore, the definition of intensive screening was clarified. The intensive screening with an intensity of 20% was to determine the growth rate and sort according to weight, retain the top 20% of the sort, and eliminate the bottom 80% of the blue crabs.

[0041] Furthermore, in step 8), the males and females are paired in a 2:1 ratio to cultivate half-twin families and full-twin families. This enriches the family types, increases genetic diversity, and provides more genetic combinations and options for subsequent breeding. At the same time, this specific pairing method helps to study the effects of different family combinations on offspring traits.

[0042] According to the family selection method of the present invention for the fast-growing strain of blue crab, based on the experience of group selection, the blue crab bred by the family selection method of the present invention can reach a specific growth rate of up to about 2.7% / d, and the yield per mu can reach more than 130 kg, which has strong economic value.

[0043] 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 design concept of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for family breeding of a fast-growing strain of blue crab, characterized in that: The following steps are involved: 1) Collecting crabs with full roe from different geographical areas, sterilizing and removing diseases from the crabs, and then placing them in a cultivation pond for culture until the end of the egg-carrying stage; 2) Move the egg-carrying crabs to the spawning bucket, collect the crab seedlings after the eggs break the membrane, and cultivate them to the fifth stage of crab larvae, then each family is subjected to intensive screening with an intensity of 20%, and the crab seedlings of different families after screening are further cultivated in different large ponds and enclosures; 3) After the crabs are grown, the male and female crabs are distinguished and further intensively screened at an intensity of 20% and the breeding is continued; 4) Different marks are placed on the plastron according to different families. After marking, the blue crabs of different families are cultured in a large pond until they molt, and then an enhanced screening with an intensity of 20% is performed again; 5) Counting and ranking the families of the remaining blue crabs after the enhanced screening to obtain the excellent families to be selected; 6) Count the number of blue crabs in each family among the selected excellent families and calculate the excellent rate P of the family A , count the weight and length of all blue crabs, calculate the overall average weight and average size, and at the same time count the average weight and average size of blue crabs in each family of the selected excellent families, and calculate the weight growth rate M of the family A and body growth rate C A ; 7) Set different weights for the excellent rate, weight growth rate, and body shape growth rate, and calculate the comprehensive score E for each family A , sorted by comprehensive scores, and finally obtained excellent pedigrees; 8) Construct a family pairing plan, separate male and female crabs from the same family, and when the female crab is about to molt, select male crabs from the corresponding family and place them in a bucket and shade them from the sun. After the female crab molts, the male crabs will mate autonomously. After mating, wait for the female crab shell to harden and collect it back. After confirming that mating is complete, one crab is cultivated in a single frame with one code, and the subsequent seedling breeding work is continued; 9) Repeat steps 2) to 8) to carry out family breeding for multiple generations.

2. The method for family breeding of a fast-growing strain of blue crab according to claim 1, characterized in that: When calculating the good and excellent rate, the total number of blue crabs remaining after screening is recorded as Stotal, and the number of blue crabs in the corresponding family is S A , then the superiority rate of the blue crab of this family 3. The method for family breeding of a fast-growing strain of blue crab according to claim 1, characterized in that: When calculating the weight growth rate, the average weight of the whole crab is recorded as Wtotal, and the average weight of the crabs in the corresponding family is recorded as W A , then the weight growth rate of the blue crab of this family is 4. The method for family breeding of a fast-growing strain of blue crab according to claim 1, characterized in that: When calculating the body growth rate, the average body size of the whole blue crab is recorded as Btotal, and the average body size of the blue crabs of the corresponding family is recorded as B A , then the body growth rate of the blue crab of this family is 5. The method for family breeding of a fast-growing strain of blue crab according to claim 1, characterized in that: When calculating the comprehensive score, the weight of the good rate is ω1, the weight of the weight growth rate is ω2, the weight of the body shape growth rate is ω3, and ω1+ω2+ω3=1. The family comprehensive score E A =(ω1P A +ω2M A +ω3C A )×100, where 100 is the adjustment coefficient.

6. The method for family breeding of a fast-growing strain of blue crab according to claim 5, characterized in that: The weights ω1=0.5; ω2=0.3; ω3=0.

2.

7. The method for family breeding of a fast-growing strain of blue crab according to claim 1, characterized in that: In the step 1), the eye stalk of the crab is cut off on one side, the temperature and salt level of the culture pond are increased, and the nutrition is fortified. The water is changed and cleaned in the culture pond every morning and the pond is dried for 30-40 minutes to promote the crab to incubate eggs at the same time.

8. The method for family breeding of a fast-growing strain of blue crab according to claim 1, characterized in that: The 20% intensity enhanced screening is to determine the growth rate and sort according to body weight, and retain the top 20% in the sort.

9. The method for family breeding of a fast-growing strain of blue crab according to claim 1, characterized in that: In the step 8), the males and females are paired in a 2:1 ratio to cultivate half-birth families and full-birth families.

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