Effects of Substituting Corn Meal for Corn Cob Meal on Diets Acceptability, Growth Response and Cost of Diets Fed to Catfish (Clarias Gariepinus)

A seventy -day feeding trial was conducted to assess the replacement value of corn cob meal as a dietary replacement for corn meal in diets of Clarias gariepinus. The corn cob was treated with 2% NaOH. The treatment reduced the fibre and increased the protein contents of the corn cob. Six isonitrogenous (40% crude protein) diets were formulated and corn cob meal was included in the diets at 0%, 10%, 20%, 30%, 40%, 50% and 100% inclusion levels designated as diets A, B, C, D, E, F, and G respectively, and diet H (commercial Coppens fish feed). The acceptability of the diets was studied using the time to strike the pellets and the acceptability index. The growth response and cost of diets were estimated. Results indicated that substituting corn meal with corn cob meal in diets fed to C. gariepinus juveniles increased the time taken by fish to strike dietary pellets. The higher the proportion of corn cob meal in the diet, the lower the acceptability of the diet to the fish. The least acceptable diet was diet G. The fish fed diet H recorded better weight gains and specific growth rate followed by the control diet and diet C respectively. There were significant differences between the control diets and the experimental diets (P < 0.05). The cost-benefit analysis showed that catfishes fed the control diets had a comparatively lower cost of diet per unit weight gain than the fish fed the corn cob-based diets. This was closely followed by diet C. This study demonstrated that corn cob meal can be successfully used to replace corn meal in the diets of Clarias gariepinus at inclusion levels of up to 30% but it is efficacious and cost-effective at a 20% inclusion level.