EFFECT OF PROTEIN TO ENERGY (P/E) RATIOS ON GROWTH PERFORMANCE, BODY COMPOSITION AND DIGESTIVE ENZYME ACTIVITIES IN ROHU, Labeo rohita FINGERLINGS

A 4 x 3 factorial experiment was performed to determine the effect of protein-to-energy (P/E) ratios for Labeo. rohita(rohu)fingerlings. Twelve experimental diets with four dietary protein (DP) levels (24, 26, 28, and 30 %) and three dietary energy (DE) levels (2400,2700, and 3000 kcal / kg) ranging from 80.00 mg / kcal to 125.00 mg /kcal P / E ratio were formulated. Each diet was randomly assigned to each triplicate group of seventeen fish averaging 6.5 +/- 0.6 g (mean +/- SD) for 10 weeks. The results showed that growth performance was highest in terms of weight gain (WG), feed conversion ratio (FCR), feed intake (FI), protein efficiency ratio (PER), specific growth rate (SGR) and digestive enzyme activities of lipase (0.567 +/- 0.05), protease (1.16 +/- 0.02) and amylase (3.43 +/- 0.02) U/mg were observed in rohu, L. rohita fingerlings fed diet containing 26% protein and 3000 kcal/kg energy, with 86.67 mg /kcal P/ E ratio. The crude protein, lipid and ash contents of fish were significantly (p > 0.05) affected by changing dietary P / E ratios. However, dry matter (DM) and gross energy (GE) contents of the fish did not improve by changing the dietary P / E ratios. In conclusion, the best protein-to-energy ratio to culture L. rohita fingerlings is estimated in 86.67 mg/kcal.