Selection for growth performance of tank-reared Pacific white shrimp, Litopenaeus vannamei

Seven growth-related traits were measured to assess the selection response and genetic parameters of the growth of Pacific white shrimp, Litopenaeus vannamei, which had been domesticated in tanks for more than four generations. Phenotypic and genetic parameters were evaluated and fitted to an animal model. Realized response was measured from the difference between the mean growth rates of selected and control families. Realized heritability was determined from the ratio of the selection responses and selection differentials. The animal model heritability estimate over generations was 0.44 +/- 0.09 for body weight (BW), and ranged from 0.21 +/- 0.08 to 0.37 +/- 0.06 for size traits. Genetic correlations of phenotypic traits were more variable (0.51-0.97), although correlations among various traits were high (> 0.83). Across generations, BW and size traits increased, while selection response and heritability gradually decreased. Selection responses were 12.28%-23.35% for harvest weight and 3.58%-13.53% for size traits. Heritability estimates ranged from 0.34 +/- 0.09 to 0.48 +/- 0.15 for harvest weight and 0.17 +/- 0.01-0.38 +/- 0.11 for size traits. All phenotypic and genetic parameters differed between various treatments. To conclude, the results demonstrated a potential for mass selection of growth traits in L. vannamei. A breeding scheme could use this information to integrate the effectiveness constituent traits into an index to achieve genetic progress.