Genetic Parameters for Growth-Related Traits and Survival in Pacific White Shrimp, Litopenaeus vannamei under Conditions of High Ammonia- N Concentrations

Özet

Based on restricted maximum likelihood (REML) method under animal model, the genetic parameters in Litopenaeusvannamei for growth-related traits on body weight (BW, g), body length (BL, cm), abdominal segment length (ASL, cm),carapace length (CL, cm), and survival (SU) under conditions of 96 hours of ammonia exposure at 14 and 21 weeks of agewere estimated, respectively. The heritability estimates for growth-related traits at different growth stages were moderate,ranging from 0.24±0.09 to 0.30±0.06 for 14-week-old shrimp and 0.26±0.07 to 0.31±0.06 for 21-week-old shrimp,respectively. The heritability estimates for survival under conditions of high Ammonia-N concentrations were 0.13±0.11 for14-week-old shrimp and 0.17±0.08 for 21-week-old shrimp, respectively. Genetic correlations between growth-related traitswithin age cohorts were generally high (ranging from 0.74±0.06 to 0.89±0.16), but for growth-related traits between ageswere low (ranging from 0.14±0.05 to 0.46±0.09); genetic correlations between growth-related traits and survival underconditions of high Ammonia-N concentrations were all positive (ranging from 0.25±0.03 to 0.32±0.05). Our results suggestthat selection to improve any single body trait would likely produce correlated responses in the other traits examined and thatselecting for growth will cause a positive correlated response in terms of Ammonia-N tolerance; estimates of geneticparameters for Ammonia-N tolerance should be calculated at a later age.