Genetic parameters for growth and survival traits in Litopenaeus vannamei at different ages

The aim of the current study was to estimate the genetic parameters for growth and survival tolerance traits in Litopenaeus vannamei at different ages (weeks 6, 10, 14, and 18). Sixty-five full-sib families (including 30 half-sib families) of L. vannamei, which were produced by 50 sires and 65 dams, were obtained by artificial insemination. There were a total of 6500 tagged shrimps representing 65 full-sib families evaluated for growth and survival traits in this study. The heritability estimates for growth traits were moderate to high (0.24 to 0.46), which suggested that selection for increasing growth traits were feasible, but the heritability of survival traits estimated on the observed scales were also low (0.01 to 0.06). The genetic correlations between growth traits (including body length and weight) within age were all positive and high, which ranged from 0.82 to 0.95 (P < 0.01). A significant correlation between growth traits showed that only selecting one growth trait for better growth and other correlated traits can be improved simultaneously. The genetic correlation between growth and survival traits within age were positive (0.02 to 0.05) at the early life stage and negative (−0.06 to −0.22) at later growth phase, which indicated that selecting for growth traits may not cause a positive correlated response in survival traits. Our results also showed that the uniformity ratio and correlation coefficient of families at adjacent growth stage increasing with age, which suggested that selection applied at early stage may result in only poor response and selection after week 14 can increase selection accuracy and accelerate the breeding process.