Influence of Duration of Water Aeration on Growth indices and Mortality rates of Heteroclarias Hybrid under Laboratory Conditions in Minna, Nigeria

Abstract

Study was carried out to determine the influence of water aeration duration ; 0.00(control), 6.00, 12.00, 24.00 hours on growth indices and mortality rate of Heteroclarias freshwater hybrid fingerlings under laboratory condition for a period of 12 weeks. Commercial diet of Crude protein (56%),Fat(15%),Crude fibre (0.4%), Ash (10.9%), Preservatives (E280), Antioxidants (E324 and E321), Vitamin A (22.50 μ/kg), Vitamin D3 (2.50 μ/kg), Vitamin E (200.00 mg/kg), Vitamin C stable (300.00 mg/kg), Phosphorus (1.8%), Calcium (2.6%) and Sodium (0.7%), respectively was fed twice daily to satiation. Growth indices and physiochemical parameters were determined weekly while the mortality rates were recorded daily. Results showed that the fingerlings cultured in 6.00 hours of aeration were significantly (P<0.05) higher in final body weight (29.82±9.34 g), weight gain (28.42 g), percentage weight gain (2030.00%) and specific growth rate (3.6% day). Mortality rates of the fingerlings cultured in 24.00hours of aeration were significantly (P<0.05) highest (70.00 + 19.38%). Water temperature (22.37±0.610C) of the fingerlings exposed to 24.00 hours of aeration was significantly (P<0.05) reduced when compared with those of 12.00-0.00 hours. Dissolved oxygen concentration (4.00±0.47 mg/L) and Biochemical oxygen demand concentration (0.95±0.54 mg/L) in control were also significantly reduced (P<0.05) when compared with those of higher treatments. Ammonia concentration (range = 0.26±0.05 to 0.28±0.05 mg/L) and water pH (7.29±0.34 to 7.58±0.49) indicated no significant differences (P>0.05) in all the treatments. The findings of this study indicated that growth indices and survival rates of Heteroclarias fish hybrid can be enhanced by using 6 hours of aeration per day