Determination of Optimum Calcium and Phosphorous Ratio for the Production of African Catfish Clarias gariepinus   (Burchell, 1822)

Optimum calcium-phosphorus (Ca/P) ratio for the growth of African catfish was investigated over a 70-day period with a basal diet formulated and supplemented with Ca/P ratios of (0:0, 1:0.5, 1:1, 2:1.5, 3:1 and 3.5: 1.5) respectively. The results showed that the mean weight gain and specific growth rate increased from the fish fed the control diet up to the fish fed diet with Ca/P ratio of 2:1.5, and then declined consistently to the fish fed diet with Ca/P ratio of 3.5:1.5. Addition of Ca and P in the diets significantly increased the carcass ash, while feeding the fish with the control diet supposed to be imbalance in Ca/P ratio elevated the carcass fat and moisture. The increase in carcass ash consequently resulted in increase (P<0.05) in carcass minerals (Ca, Mg, P, Zn and Fe) in relation to fish fed the control diet. In conclusion, the study suggests Ca/P ratio of 2:1.5 (1.33:1) as the optimum for the production of African catfish.

Keywords
African catfish; Ca/P ratio; growth performance; nutrient digestibility