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 x O. mossambicus) and Nile tilapia (O. niloticus) reared in concrete tanks for 60 days. The juvenile of Nile tilapia, T1 (mean weight 2.08 +/- 0.2 g) and hybrid red tilapia, T2 (mean weight 2.07 +/- 0.16 g) were stocked in concrete tanks (15 x 6 x 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 +/- 0.1g), while the lowest one was recorded in T1 (34.3 +/- 0.2 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/m(3)/60 days and for T1 was found to be 8.58 kg/m(3)/60 days (P<0.05). Water quality parameters (temperature 28.3 +/- 0.14 degrees C, dissolved oxygen 6.4 +/- 0.07 mg/l, pH 6.8 +/- 0.07, ammonia 0.002 +/- 0.00 mg/l, hardness 107.1 +/- 1.4 mg/l and nitrite 0.145 +/- 0.00 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 x O. mossambicus) has potential for aquaculture in Pakistan.