Author: Yusuf, Ismaila Abayomi

Fifteen weeks (105 days) feeding trials were conducted on growth response and economic benefit of replacing fishmeal with cattle hoof meal (CHM) in the diets of African catfish (Clarias gariepinus) juveniles. The objectives of the research were to determine the growth performance, feed utilization, apparent digestibility, carcass composition and cost effectiveness of C. gariepinus fed with varying substitution levels of fish meal with cattle hoof meal. Five isonitrogenous diets containing 42% crude protein were formulated in which CHM replaced fishmeal at 0, 25, 50, 75 and 100% coded as D2, D3, D4, D5 and D6 respectively. A commercial feed (D1) was used as reference diet. Two hapa partitioned into six treatments of three replicates each embedded in a concrete pond of 5m by 3m by 2m was used for the experiment. The fish were fed at 3% body weight three times daily between the hour of 6.00 and 7.00am, 2.00 and 3.00pm, and 10.00 and 11.00pm. The feeding ration was adjusted every three weeks after weighing. The mean physico chemical parameters of the water in the experimental tank were within the acceptable range for optimum growth of C. gariepinus. Cattle hoof meal contained 58.06% crude protein, 2.75% crude fibre, 3.25% crude lipid, 0.08% phosphorus, 0.09% potassium, 0.24% calcium and 19.59% sulphur. Some essential amino acids recorded were leucine (7.15g/100g), lysine (4.29 g/100g), methionine (2.19 g/100g) and tryptophan (0.81g/100g). Feeding trials indicated that all fish consumed the experimental diets actively. The fish fed the control diet with no cattle hoof meal (D2) had lower weight gain compared to the fish fed 25% CHM. The fish fed 50% CHM, 75% CHM and 100% CHM showed a decreasing weight gain (148.60g, 143.73g and 129.00g respectively) as the substitution level of the CHM meal increased. The fish fed with 25% cattle hoof meal (D3) had the best growth performance and feed utilization proficiency (SGR 2.58, RGR 1403, PER 1.67 and FCR 1.47) among the fish fed the formulated diets (D2, D3, D4, D5 and D6). There was no significant difference (p˃0.05) in the survival value of fish fed with all the experimental diets. The apparent digestibility coefficient of the feed fed to Clarias gariepinus decreased with increasing level of substitution of fish meal with CHM. Carcass composition of the fish revealed that all the fish fed the experimental diets had higher carcass protein, lipid and ash contents but lower nitrogen free extract content than the initial fish sample. The fish fed D3 had the best Net profit (₦46.53) followed by D6 (₦45.63), D1 (₦42.54), D5 (₦41.61), D4 (₦31.49) and D2 (₦20.59) in decreasing order. This experiment revealed that CHM can replace fishmeal at a lower cost and efficient diets for Clarias gariepinus. The best result was produced at the substitution level of 25% inclusion of CHM. It is recommended that CHM be included in the feed of Clarias gariepinus at 25% for optimum growth performance and reduced cost of production. Field experiment especially the semi intensive system in earthen ponds is suggested. Further studies with CHM using other cultured species are highly recommended