Comparison of growth, feed conversion and body composition of juvenile hybrid red tilapia (Oreochromis niloticus x O. Mossambicus) and nile tilapia (O. Niloticus) reared in concrete tanks

The objective of this study was to compare growth, feed consumption and body composition of hybrid red tilapia (Oreochromis niloticus O. mossambicus) and Nile tilapia (O. niloticus) reared in concrete tanks for 60 days. The juvenile of Nile tilapia, T1 (mean weight 2.08\ub10.2 g) and hybrid red tilapia, T2 (mean weight 2.07\ub10.16 g) were stocked in concrete tanks (15 6 3 ft). They were fed with four isoenergetic (20.3 kJ g-1) diets containing 35% protein at a daily ration of 5% body weight with two replications. The highest weight gain was found in T2 (44.2\ub10.1g), while the lowest one was recorded in T1 (34.3\ub10.2 g). Specific growth rate (SGR) and feed conversion ratio (FCR) were not significantly different among treatments (P<0.01). Survival remained 100% in T2, while 94% was observed in T1. Condition factor was found to be significantly different among the groups (P<0.01). The hepatosomatic index (HSI) was greater in T2 that of T1. Production of T2 was 11.05 kg/m3/60 days and for T1 was found to be 8.58 kg/m3/60 days (P<0.05). Water quality parameters (temperature 28.3\ub10.14C, dissolved oxygen 6.4\ub10.07 mg/l, pH 6.8\ub10.07, ammonia 0.002\ub10.00 mg/l, hardness 107.1\ub11.4 mg/l and nitrite 0.145\ub10.00 mg/l) were recorded throughout the study period. The values of biochemical constituents including fatty acids of the fish in T1 and T2 did not show prominent changes (P<0.05), though little variations were noted in the values of individual fatty acids. Based on the biological and chemical data, it is suggested that hybrid red tilapia, T2 (O. niloticus O. mossambicus) has potential for aquaculture in Pakistan