Genetic parameters for growth and survival traits in Pacific white shrimp Penaeus (Litopenaeus) vannamei from a nucleus population undergoing a two-stage selection program

A multivariate animal model and multi-generational data from a two-stage selection shrimp breeding program were used to estimate genetic parameters for a genetic nucleus of Penaeus (Litopenaeus) vannamei. A total of 408,648 records from years 2008 to 2010 production cycles provided by a Mexican hatchery were analyzed. The studied traits were survival from 0 to 28 days of age (S1), square root of body weight at 28 days of age (W1^1/2), survival from 65 to 130 days of age (S2), and body weight at 130 days of age (W2). Mean (standard deviation) for W1^1/2 and W2 were estimated as 5.4 mg^1/2 (1.55) and 13.6 g (3.1), respectively, while mean (standard deviation) for S1 and S2 (as proportions) were estimated as 0.20 (0.41) and 0.71 (0.45), respectively. Heritabilities for S1, W1^1/2, S2, and W2 were 0.03 ± 0.01, 0.13 ± 0.03, 0.04 ± 0.01, and 0.21 ± 0.04, respectively. Genetic correlations of S1 with W1^1/2, S2, and W2 were ?0.49 ± 0.21, ?0.29 ± 0. 21, and ?0.40 ± 0.16, respectively. Genetic correlations of W1^1/2 with S2, and W2 were 0.55 ± 0.17, and 0.71 ± 0.12, respectively, and genetic correlation between S2 and W2 was 0.56 ± 0.10. Results show that selection based on W2 has a positive effect on S2, while selection based on W1^1/2, as an early selection criterion, would increase the selection responses for W2 and S2.