Optimal lipid : carbohydrate and protein : energy ratios in semi-purified diets for juvenile black tiger shrimp Penaeus monodon Fabricius

This study aimed at determining the optimal lipid:carbohydrate and protein: energy ratios for growth and survival of juvenile Penaeus monodon Fabricius , Two experiments were performed using completely randomized designs in sem i-closed recirculating water systems. Juveniles of 0.4-0.8 g in weight and 4.0-5.5 cm in length stocked at a density of 80 individuals m(-2) were fed semi-purified diets. The first experiment determined optimal lipid:carbohyd rate using isonitrogenous (35%) and isocaloric (330 kcal 100 g(-1)) diets w ith five lipid:carbohydrate ratios: 4:39, 7:32, 9:25, 14:18 and 16:12 (% wt /wt). The lipid:carbohydrate ratio of 7: 32 gave the highest growth rate (P <0.05), while survival rates of shrimp in all other diet groups were simila r but less. Thus, optimal lipid:carbohydrate ratio for the juvenile tiger s hrimp was approximate to 1:4.6. In the second experiment, optimal protein:e nergy (P:E) ratio was studied using five protein levels (25%, 30%, 35%, 40% and 45%) with a fixed lipid:carbohydrate ratio of 1:4.6. Nine diets contai ning energy content (203-459 kcal 100 g(-1)) with protein:energy ratio (63- 171 mg protein kcal(-1)) were formulated, Shrimp fed the diet containing 33 -44% protein and an energy content of 223-371 kcal 100 g(-1) had a signific antly higher growth rate than those fed the other diets (P < 0.05), A regre ssion analysis indicated that an optimal P:E ratio for optimal growth and s urvival of juvenile tiger shrimp was 150 and 146 mg protein kcal(-1) respec tively. This diet contained 33-44% protein and had optimal energy of 263-33 1 kcal 100 g(-1).