ABSTRACT

 A study was undertaken to assess the effect of two feed sources on growth, body composition and grow-out economics of Heterobranchus longifihis. Three isonitrogenous diets of 42% crude protein were used. Diets 1 and 2 were two different brands of commercially available feed while diet 3 was a farm-made feed compounded from locally available materials (blood meal, soybean and maize using cassava flour as binder). Groups of five H. longijIlis were stocked into 70- litre plastic bowls and were fed the diets. The diets were assigned in triplicate in a completely randomized design to the groups of fish. In treatment 1, fish were fed diet I (one of the commercial diets), in treatment 2, fish were fed diet 2 (the second commercially available diet) and in treatment 3, fish were fed the farm-made feed. The diets were fed at the rate of 1% fresh body weight thrice daily. The experiment lasted for 154 days (22 weeks). Water was monitored for ammonia and nitrite levels. Water was changed every 3 days as suggested by the results of the ammonia and nitrite test. Dissolved oxygen, pH and temperature were also taken. The fish were weighed every two weeks for determination of weight gain, specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER), feed conversion efficiency (FCE) and final weight. Growth and feed performance indices were analyzed for significant differences between the treatments using the ANOVA and T- test. The economic indices taken were: economic conversion ratio (ECR), economic weight gain (EWG) and the cost: benefit. After the 154 days feeding period, it was found that the commercially available feed sources had the best growth performance than the farm-made feed. Treatment 2 had the best FCR, FCE, and PER which are not significantly different from treatment 1 (p > 0.05) but significantly different from treatment 3 (p <0.05). Treatment 1 had the best final weight, weight gain, percentage weight gain and SGR which were also not significantly different from treatment 2 (p >0.05), but significantly different from treatment 3 (p < 0.05). Treatment 2 had the best ECR which is significantly different (p < 0.05) from all the other treatments and EWG which are not significantly different from treatment 1 (p > 0.05) but significantly different from treatment 3 (p < 0.05) and treatment 3 had the least. The cost: benefit was 1:1.40, 1:1.45 and 1:0.61 for treatment 1, 2 and treatment 3 respectively for total cost and 1:1.32, 1:1.35 and 1:0.56 for treatment 1, 2 and 3 of the variable cost. The result of the experiment shows that treatment 2 had the best growth performance and cost: benefit ratio. Nevertheless, treatment 3 had a low feed cost and production cost, suggesting that mixed feeding using commercially available feed and farm-made feeds may present the best option for grow-out of the species given the prevailing socio-economic situation that determines selling price.