Growth and immune parameters in white shrimp Litopenaeus vannamei reared at different salinities

Abstract

Growth and immune parameters were examined in white shrimp Litopenaeus vannamei juveniles (0.42 ± 0.01 g) individually caged and reared at salinities of 2.5 per mille, 5 per mille, 10 per mille, 15 per mille, 25 per mille, and 35 per mille for 24 weeks. Survival rates were 20%, 40%, 77%, 83%, 90%, and 90%, respectively. The weights and lengths of shrimp reared at 25 per mille and 35 per mille for 24 weeks were significantly higher than in shrimp reared at 2.5per mille and 5per mille, and specific growth rates (SGR) of shrimp reared at 25per mille were significantly higher than in shrimp reared at 2.5per mille, 5per mille, 10per mille, and 15per mille. Shrimp reared at 15per mille, 25per mille, and 35per mille had more hyaline cells, granular cells, total hemocyte count,phenoloxidase (PO) activity, respiratory burst, superoxide dismutase activity, and lysozyme activity compared to shrimp reared at 2.5per mille, 5per mille, and 10per mille. In conclusion, juvenile shrimp should be maintained in salinities above 10per mille to avoid reductions in immunity.白蝦(0.42 ± 0.01 g)分別飼養於鹽度千分之2.5、千分之5、千分之10、千分之15、千分之25及千分之35，經24週後，檢測成長與免疫因子。活存率分別為20%、40%、77%、83%、90%及90%。飼養於鹽度千分之25與千分之35的白蝦，經24週後，其體重與體長明顯高於飼養在鹽度千分之2.5及千分之5。飼養於鹽度千分之25的白蝦，其特定成長率(SGR)明顯高於飼養在鹽度千分之2.5、千分之5、千分之10及千分之15。白蝦飼養於鹽度千分之15、千分之25及千分之35，其透明球、顆粒球、總血球、酚氧化酵素活性、呼吸爆、超氧歧化酵素活性及溶菌酵素活性皆高於白蝦飼養於鹽度千分之2.5、千分之5及千分之10的水中。因此，白蝦應飼養於鹽度千分之10以上的環境，以避免其免疫力的下降。