Analysis Of Animal Models And Estimation Of Genetic Parameters In Fenneropenaeus Chinensis Breeding

Brood stock was collected from both domesticated breeds ("Huang Hai 1" and "Jikang-98") and wild populations in China and South Korea to establish a base population of Fenneropenaeus chinensis with a broad genetic variation. The families were successfully produced using oriented mating and artificial insemination. The crossbreeding of F. chinensis and genetic parameters estimates were carried out. The results indicated that obvious genetic improvement was gained in F. chinensis. Therefore, the multi-traits selection was necessary for shrimp genetic breeding program. The results would provide theoretic basis for indirect and early breeding for F. chinensis. The following is the results in detail.1.Technical operation of selective breeding for F. chinensisTechnical operation of Selective breeding for F. chinensis is established.1) Composite of base population:base population was collected from both domesticated breeds ("Huang Hai 1" and "Jikang-98") and wild populations in China and South Korea to establish a base population of F. chinensis with a broad genetic variation.2) Over-wintered and ripened of spawners:the percentage of spawning females are increased by Eyestalk ablation.3) Oriented mating and Artificial insemination: F. chinensis families were produced by carrying out oriented mating so as to select the offsprings in selective breeding of F. chinensis. We used 4 different methods of artificial insemination (AI), namely the entire spermatophores transplantation, the fractional spermatophores transplantation, the sperm duct transplantation and the seminal fluid transplantation.4) Larvae rearing and post-larval nursing:larvae rearing of standardized technical operation for F. chinensis.5) Post-larvae tagging:family coding using elastomers:all families, which are cultured in the controlled environment, are challenged with White Spot Syndrome Virus (WSSV).6) Post-larval rearing.7) Individual tagging:at harvest, all breeding candidates from the genetically superior families are individually tagged using unique eye-tags.8) Testing of growth, survival and WSSV-challenge:tagged test animals from different families were tested with growth, survival and WSSV-challenge in a common test environment. The growth, pond survival and WSSV-resistance and pond survival were measured including all recorded data.2.Establishment of families and their growth and development for F. chinensisF. chinensis families were produced by carrying out 4 different methods of artificial insemination (AI).155 cases of artificial insemination experiment were totally applied,108 spawners succeeded in spawning and hatching the larvae, with 69.7% of the ratio. And then on basis of the experiment,101 full-sib families that included 29 half-sib families of F. chinensis were established. The larval growth and development were studied, such as fertilization rate, hatching rate, survival rate and growth were compared. There were no significant differences among four different experimental groups (RS (♀)×RS (♂),QD(♀)×RS(♂),KC (♀)×RS (♂) and KC (♀)×QD (♂)). In addition, there were no significant differences between other families that were studied in the experiment at early life history stage of F. chinensis. During growout, analyses of variance for growth indicated there was most significant difference (P<0.01) among families.3. The effects of different diets and stocking density on the growth and survival rate of post-larval nursing of families of F. chinensisUnder the identical genetic ground, we studied the effect of different diets and stocking density on the growth and survival rate of juvenile shrimp F. chinensis in small water bodies. Groups of juvenile shrimps F. chinensis were cultured using three diets of artificial pellets, frozen fresh fish and living Artemia sp. at four stocking densities (50,100,150,200 shrimps per tank, respectively). The results showed that the diets and the stocking density had great effects on growth and survival rate of juvenile shrimps F. chinensis. Analyses of variance for growth of juvenile shrimps F. chinensis indicated there were significant differences among different diets, densities, diets and densities (P<0.01). The growth of juvenile shrimps F. chinensis fed on Artemia sp. was the fastest in growth. The behavior and the weight gain of shrimps were affected by stocking density. The results showed that shrimps held at the higher density showed lower weight gain than those at lower densities. The variation in shrimp weight gain was greatest in the highest density group. The results showed that the four different diets and stocking density had a significant effect on survival rates over the experimental period. Shrimps held at different stocking density showed with increase of stocking density the survival rates of fish was suppressed. However, different diets had different effect on survival rates from 58.1% up to 85.2%. The group of juvenile shrimps F. chinensis fed on Artemia sp. with stocking density (50 shrimps per tank) had the highest survival rate of 85.2%. The group of juvenile shrimps F. chinensis fed on artificial pellets had not significant effect on survival rates at four different stocking densities. The group of juvenile shrimps F. chinensis fed on frozen fresh fish had significant effect on survival rates.4. Studies on hybridization among the different populations of shrimp F. chinensisF. chinensis were collected from two different geographic areas in Rushan Bay of China and the South Coast of the Korean Peninsula. Intra-and intercross populations were produced between Rushan (RS) and Korean (KN) selected populations. Descendants of 3 groups were produced using hybrid duplex. All descendants of the above group were selected for the research on the growth trait and viability at the end of fourth month. The results indicated that growth trait and viability of two intercross populations showed a range of heterosis, ranging from 3.586% to 13.892%, and that KN♀×RS♂has a stronger heterosis than KN♀×RS♂. The result of ANOVA indicated that there was significant difference (P<0.05) on BL, BW of hybrids of Rushan (RS) and Korean (KN) selected populations with their parental populations while Sur was not significantly different (P>0.05). The multiple comparisons of LSD test indicated that the two intercross populations were significantly different (P<0.05) from their parents in BL. The results of hybrid duplex indicated that RS♀×(KN'×RS')♂had a better growth and viability than (KN'×RS')♀×RS♂and (RS'×KN')♀×RS♂, (KN'×RS')♀×RS♂had a better growth and viability than (RS'×KN')♀×RS♂. The result of ANOVA indicated that the descendants of all populations and cross combinations were significantly different in BL and Sur. The multiple comparisons of LSD test indicated that there was significantly difference between RS♀×(KN×RS)♂and (RS×KN)♀×RS♂(P<0.05) in BL and Sur. In addition, among descendants of intra-, intercross populations and hybrids duplex RS♀×(KN×RS)♂had a best growth and viability.5. Analysis of Animal Models and Estimation of Genetic Parameters of growth in juvenile F. chinensisBased on the data of 1387 animals from 21 half-sib groups of Fenneropenaeus chinensis, breeding value of body weight of all individuals were estimated using four kinds of animal (A,AB,AF,AFB) models of BLUP (Best linear unbiased prediction). These models were composing of different combinations which included average body weight when tagging family (covariate) or full-sib group effect (uncorrelated random effect) or these two factors. Results implied that these two factors were very import for estimating breeding value of body weight. The accuracy of breeding value estimated by ABF model was higher than other models. The heritability estimated of 145d body weight by ABF model was 0.14±0.076. For body weight selection, the efficency of breeding value selection is increased by 50% and 80.59% in family selection and individual selection, compared to phenotypic value selection.6. Estimation of genetic parameters of body weight, survival rate and resistance to WSSV in shrimp F. chinensisThe breeding values of three traits about the body weight of 170 days, the survival time for resistance to White Spot Syndrome Virus (WSSV) and the survival rate were estimated using single trait animal model, and the correlation analyses between the phenotypic value and the breeding value among traits was performed at family level. The results indicated that the estimated heritability of three traits were 0.22±0.16,0.14±0.12 and 0.03±0.021, respectively, and the breeding value of each trait was calculated basing on these values. At family level, the correlation analyses of trait phenotypic value showed that the correlation coefficient between the average body weight of 170 days and the resistance to WSSV is positive and significant (r=0.35, P<0.05), and the correlation coefficients among other traits were very small, and the differences were not distinct. The correlation coefficients of family breeding value between three traits were all small, among which the correlation coefficient between body weight of 170 days and resistance to WSSV was highest (0.038), and the correlations between body weight of 170 days and tank survival, between the survival time of resistance to WSSV and pond survival were negative (r=-0.24, r=-0.027), respectively, and their differences were not distinct. Estimated breeding values for the above traits were combined in a multi-trait selection index to estimate a total breeding value of the breeding candidates. The next generation of families were Selected to produced based on Selection index values.7.Genetic gain for selection of F. chinensis applying BLUP methodIn order to evaluate genetic gain of BLUP (best linear unbiased prediction) for Fennropenaeus chinensis, the experiment on growth comparison of breeding generation of F. chinensis was carried out. Groups of the experiment on growth comparison consisted of three breeding sires of families of the high breeding value as the experimental group and three middling breeding value as the control group. The offspring of six families were stocked into separate larvae-culture tanks for rearing until tagging. The six families produced were tagged with a unique family code by injecting different colors of "Visible Implant Fluorescent Elastomers" (VIE). The animals had an average body weight of 1.0 grams at tagging. The breeding candidates were stocked in the tanks and harvested after 18 weeks. The expecting genetic gain of the growth trait was estimated to be 0.78g,11.68% increased to average value 6.68g. The test results show that the average body weight of the offspring of high breeding value families was 21.56g, the average body weight of the offspring of the middling breeding value families was 19.03g, the phenotypic gain of the body weight was 13.28%. The results indicated that obvious genetic improvement was gained by BLUP breeding value estimation.