Current Journal of Applied Science and Technology

Feeding experiment was conducted for 45 days to evaluate the effects of salinity on the feeding efficiencies, growth performances and survival rate of 11^th strain of tilapia, Oreochromis niloticus (GIFU) in laboratory condition. Three rectangular glass tanks were used for the experiment with different level of salinity (0 as control; 8ppt and 10ppt (ppt means parts per thousand, g/l) as treatment 1 and treatment 2 respectively) using two replicates for each level of salinity. Seventy-five fingerlings were stocked in the tanks. The investigation was conducted at one feeding rate (3% of body weight) which has given twice a day in a 1 X 2 factorial experiment. Average food conversion ratios (FCR) were 2.66 ± 0.04, 1.76 ± 0.04 and 1.69 ± 0.07 in controls, T₁, and T₂ respectively. Average protein efficiency ratios (PER) were 0.63 ± 0.04, 1.31 ± 0.01 and 1.68 ± 0.02 in control, T₁, and T₂ respectively. The feed efficiency (FE) were 35.22 ± 1.54, 32.45 ± 1.22, and 31.54 ± 1.85 in control, T₁ and T₂ and specific growth rate (SGR) were 0.42 ± 0.03 %/d in control, 0.99 ± 0.03 %/d in T₁ and 1.34 ± 0.09 %/d in T₂ respectively. The net weight gain of fish in T₂ (39.12 ± 0.17 g) and T₁ (31.1 ± 0.02 g) were significantly higher than that of control (30.00 ± 0.21 g). The net length gain of fish in T₂ (12.12 ± 0.03 cm) and T₁ (10.5 ± 0.02 cm) were significantly higher than that of control (9.5 ± 0.04 cm). The survival rates were 85%, 100% and 100% in C, T₁ and T₂ respectively. The proximate composition of fishes, water quality parameter, feeding efficiencies and growth performances were better in T₂ than that of T₁ and C. The best growth was found from T₂ (salinity 10 ppt) and lower growth was found from control (salinity 0 ppt) in case of GIFU. The present study revealed that GIFU can tolerate a wide range of salinity and shown better growth and survival rate.