Effect of dietary soy-lecithin on growth and body composition of Indian black tiger shrimp Penaeus monodon (Fabricius, 1798) reared under hyperosmotic stress condition

Abstract

Sixty days feeding trial was conducted to study the effect of dietary soy-lecithin (phosphatidylcholine) as a source of phospholipids on the growth performance of Penaeus monodon (Fabricius, 1798) reared at hyperosmotic stress conditions (40‰) in indoor tanks. Four experimental diets viz., DL-1 (Control), DL-1.5, DL-2 and DL-2.5 were formulated by including soy-lecithin at the rate of 1, 1.5, 2 and 2.5%, respectively. The results revealed that the daily growth coefficient (DGC) significantly (p<0.05) increased from 1.44 to 1.67% day-1 when the inclusion levels were increased from 1 to 2.5%. The relative growth rate (RGR) was significantly (p<0.05) high in the groups fed on DL-2 and DL-2.5 diets than in the groups fed other diets (DL-1 and DL-1.5). Compared to DL-1, all the other diets (DL-1.5, DL-2 and DL-2.5) had increased DGC by 7.81, 11.06 and 15.89% and decreased feed conversion ratio (FCR) by 8.70, 8.83 and 9.56%, respectively. The dietary treatments had no significant difference in survival (75.56-82.22%) and carcass composition except body lipid, which was significantly (p<0.05) high (3.66%) in DL-2 and DL-2.5 fed groups compared to DL-1 and DL-1.5 (3.25-3.42%). Carcass phospholipids increased (p<0.05) from 61.96 to 69.69% with increasing dietary soy-lecithin levels, while triacylglycerides (p>0.05) and cholesterol (p>0.05) were not affected. The inclusion levels of soy-lecithin had no significant influence on the fatty acid composition of P. monodon except for C16:0 and C18:2c, which were high (p<0.05) in the groups fed DL-2 and DL-2.5 diets. Results concluded that soy-lecithin as a source of phospholipids can be more effective at hyperosmotic stress conditions and could be included at >2.5% in the diet of P. monodon.