Evolution of genetic variability for growth-out survival rate in a selected population of Pacific white shrimp Penaeus (Litopenaeus) vannamei

Abstract Text: Data from 164,023 offspring from 698 sires and 945 dams were used to estimate changes in the genetic variability for grow-out survival rate from 65 to 130 days of age (SR) in the 2004-2010 production cycles (7 generations), from a population of Pacific white shrimp selected for growth rate and SR. Estimation of variance components was performed using linear animal models with ASReml software. The fixed effect was year-pond combinations. Random effects were additive genetic, full-sib common environmental effects, and residual. Variances were considered as heterogeneous across years using full pedigree information. Also, within-year analyses were performed with similar models, but using only the pedigree information from that year. Estimates of trends for additive genetic variance, heritability and additive genetic coefficient of variation across years showed significant departures from linearity, suggesting the absence of a decline in the genetic variability.

Keywords: genetic variability, survival rate, shrimp