Selective Breeding of Pacific White Shrimp (Litopenaeus vannamei) for Growth and Resistance to Taura Syndrome Virus

From 1995 to 1998, the Oceanic Institute operated a breeding program for Pacific white shrimp, Litopenaeus vannamei, based on a selection index weighted equally for growth and resistance to Taura Syndrome Virus (TSV). In 1998, two separate breeding lines were established. One line was selected 100% for growth (Growth line) and a second line was selected on an index weighted 70% for TSV resistance and 30% for growth (TSV line). After one generation of selection, select shrimp from the Growth line were 21% larger than unselected control shrimp (24.2 vs. 20.0 g). The half-sib heritability (h(2)) estimate for growth was 0.84 +/- 0.43(s.e.) and realized h(2) was 1.0 +/- 0.12. Females were 12.7% larger than males. Shrimp tails accounted for 65.1% of total body weight and males had a significantly higher percent tail than females (65.7% vs. 64.5%; P \u3c 0.001). Half-sib h(2) for percent tail was 0.15 +/- 0.12. In the TSV line, there was an 18.4% increase in survival to TSV between select and control shrimp after one generation of selection (46.4% vs. 39.2%). Realized h(2) for TSV resistance was 0.28 +/- 0.14 and h(2) on the underlying scale was 0.30 +/- 0.13. However, select shrimp in the TSV line were 4.6% smaller than control shrimp (22.6 vs. 23.7 g) and there was a negative genetic correlation between mean family growth and mean family survival to TSV [-0.46 +/- 0.18(s.e.)]. Percent females per family ranged from 39.7% to 69.2% and averaged 51 % female, but h(2) for sex ratio was zero, indicating that it is not feasible to select for a higher percentage of females. Significant improvements in growth and TSV resistance can be made in L. vannamei through selective breeding; however, the negative genetic correlation between growth and TSV resistance must be considered when developing breeding plans. (C) 2002 Elsevier Science B.V. All rights reserved