Estimation of Additive and Dominance Genetic Variances for Growth and Multiple Stress at Different Ages in Pacific White Shrimp Litopenaeus vannamei

Abstract

This study aimed to estimate the additive and dominance genetic variance in growth and multiple stress‐tolerance traits in 7 week and 15 week Litopenaeus vannamei shrimp. Four different animal models were studied by including all or different subsets of the following effects: additive genetic effects (A), additive genetic and common environmental effects (A+C), additive genetic and dominance effects (A+D), and additive, common environmental, and dominance effects (A+D+C). Variance components were estimated using the Average Information Restricted Maximum Likelihood (AIREML) method. In general, estimates of additive genetic variance were inflated under the simple model (A) and decreased remarkably under the more complex models (A+C, A+D, and A+D+C). The genetic parameters of two‐stage (7 week and 15 week shrimp) growth and multiple stress‐tolerance traits were more suitable for estimation using the A+C model. The additive effects (0.311~0.754) of seven traits in 7 week shrimp were greater than the dominance effects (4.950× 10‐7~0.201), whereas the additive effects of the same seven traits in adult shrimp ranged from 7.712×10‐8 to 0.468 and the dominance effects ranged from 0.074 to 0.577. Except for survival time, carapace length, and carapace width, the additive effects of the other traits were smaller than the corresponding dominance effects. Thus, better genetic improvement of 7 week and 15 week shrimp growth and multiple‐stress tolerance can be obtained with selective breeding than with cross‐breeding, and better genetic improvement of 7 week shrimp growth traits can be obtained with cross‐breeding than with selective breeding. Our study further enriches the database for enhancing growth and stress resistance in L. vannamei and provides reference information for growth improvement and multiple stress‐resistance breeding.