Growth performance and body composition of Oreochromis niloticus reared at different water temperatures

We evaluated the growth performance and body composition of Oreochromis niloticus reared at different water temperatures (23, 26, 29 and 32 degrees C) and fed a standard diet twice daily of about 3% of their body weight for a period of 58 days. The total weight gain and specific growth rate of fish differed significantly (P < 0.05) at different water temperatures and increased with the increase in temperature up to 29 degrees C, after which no significant increase was observed. The values for the feed conversion ratio (FCR) decreased with the increase in water temperature indicating a better utilization of feed per unit live weight gain. The differences were however non-significant at 29 and 32 degrees C. Differences were also observed in the body composition of fish. Fat and ash contents decreased and moisture content increased as the water temperature increased, whereas the crude protein and gross energy contents of fish were not affected (P > 0.05). Our results suggest that the optimum temperature for Oreochromis niloticus lies somewhere near 29 degrees C.