Processed knife fish Chitala ornata (Gray, 1831) meal as fishmeal replacement in diets improves performance of juvenile nile tilapia Oreochromis niloticus (Linnaeus, 1758)

A 60-day feeding trial was conducted to assess the effects of Knife fish (Chitala ornata) meal (KFM) as fishmeal replacement in diets of Nile tilapia (Oreochromis niloticus) juveniles. Iso-nitrogenous and isolipidic diets were used which is composed of a control diet and four basal diets with 25, 50, 75 and 100% KFM inclusions. With a stocking density of 15 fish per tank, O. niloticus juveniles were distributed randomly in fifteen 30-L rectangular tanks for the evaluation of growth performance, feed utilization, blood chemistry, fish body and carcass composition. KFM diets generally enhanced the growth performance and feed utilization while having no adverse effects on the body composition and blood chemistry of Nile tilapia juveniles. Statistical treatment of the data affirmed the significant improvement on the weight gain, growth rate, Feed Conversion Ratio (FCR), Protein Efficiency Ratio (PER) and major blood serum parameters for KFM fed fish. Cost analysis was also conducted to determine the economic efficiency of KFM diets. Cost analysis exhibited increasing feed cost up to 75% KFM fed fish due to increasing feed intake and higher production costs of KFM diets. The incidence cost of 75% KFM fed fish was also the highest among the treatments as well as on its profit index. Higher costs for the production of the 75% KFM diets can be compensated by higher profit index and fish weight gain. With all these findings, it can be suggested that 75% KFM diet is the optimal level of fishmeal replacement to achieve better growth performance in Nile tilapia juveniles