| EFFECT OF DIETARY PROTEIN AND ENERGY LEVELS ON THE PERFORMANCE OF NILE TILAPIA, OREOCHROMIS NILOTICUS, FRY IN TOLERATING LOW TEMPERATURES OF WINTER SEASON IN EGYPT |
| FAYED, WALIED M.A., Faculty of Agriculture (Saba Basha), Alexandria University, Alexandria, Egypt, email: fayedwal@gmail.com; Sallam, Ghada R.A., email: fayedgha@gmail.com. |
| The effect of dietary protein and energy levels on the performance of Nile tilapia, Oreochromis niloticus, fry was examined throughout the winter season. Six practical diets containing three protein (30, 35, and 40%) and two energy (370 and 470 kcal GE /100 g) levels were formulated for this study. The diets were fed to fry (initial weight 1.03g) to satiation, two times a day, for 6 months. At all protein levels, groups of fry fed low-energy diets (370 kcal GE /100g) revealed poor growth and feed conversion efficiency, accompanied with high mortality rates, compared to those fed high-energy (470 kcal GE /100g) diets. At dietary protein levels from 35 to 40%, fish growth and survival rates were significantly improved by increasing dietary energy from 370 to 470 kcal GE /100g. However, the best growth and feed utilization were obtained with 40% protein and 470 kcal GE /100g diet. Body composition was significantly affected by both dietary protein and energy levels. The body moisture, protein and lipid content were positively correlated (directly proportion) to dietary protein and energy levels. The findings of the present study recommend that O. niloticus fry require 40% protein and 470 kcal GE /100 g for maximum growth and best survival rate when reared in earthen ponds to overcome the low winter season temperatures.
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