Effect of Dietary Protein: Energy Ratios on Nutrient Digestibility in Labeo rohita Fingerlings

This study investigated the effects of dietary protein to energy (P/E) ratios on the nutrients and minerals digestibility of Labeo rohita fingerlings. Twelve experiment diets containing four protein levels (24, 26, 28, and 30 %) at three dietary energy levels (2400, 2700, and 3000 kcal/kg) with P/E ratios from 80.00 to 125.00 mg / kcal were evaluated. Each diet was randomly assigned to triplicate groups of seventeen fish averaging 6.5 +/- 0.6 g (mean +/- SD) for 10 wk. The chromic oxide in the diets was added as an additional inert marker to determine the digestibility of nutrients. The results from present study were demonstrated that the dietary P/E ratio significantly affects digestibility of protein, lipid and gross energy. In addition, the interactions of protein and energy significantly (p 0.05) affected the digestibility of crude proteins, lipids, gross energy however, no significant (p 0.05) effect was observed in digestibility of dry matter and ash. The increasing dietary P / E ratio significantly increased the digestibility of Na, Ca, P, Cu, Mn, Zn, and Fe. The diet with P / E ratio of 86.67 mg / kcal showed higher digestibility of dry matter (69.38 +/- 1.06), crude protein (88.18 +/- 1.59), lipid (93.43 +/- 0.22) and gross energy (86.50 +/- 0.57) while lower digestibility was observed in D12 (dietary protein 30% and dietary energy 3000 kcal/kg) with P/E ratio 100.00 mg / kcal. In conclusion, P/E ratio of 86.67 mg digestible protein / kcal digestible energy shows the maximum digestibility of nutrients and minerals in Labeo rohita fingerlings.