Effects of Black Soldier Fly (Hermatia Illucens Burchell, 1822) Larvae Based Diets on Growth Performance, Carcass Composition and Economic Efficiency of African Catfish (Clarias Gariepinus Linnaeus, 1758)

The aquaculture industry is often considered as the future solution to the dwindling wild fish capture. The expansion of aquaculture faces a significant obstacle in the form of inadequate fish output due to lack of affordable quality feeds. In sub-Saharan Africa, fish feed protein ingredients are among the most expensive and often unavailable of all feed ingredients. Fishmeal is the primary source of protein for fish feeds in Kenya’s aquaculture industry; however, it is expensive and is sometimes tainted, which leads to a reduction in the industry’s overall productivity. Due to this issue, there is a pressing need to investigate alternative protein sources that are less costly and more readily available, such as the Black soldier fly larvae meal. A 12-week feeding experiment was done to evaluate effects of replacing fishmeal with black soldier fly larvae meal on growth performance, carcass composition and economic efficiency of African Catfish (Clarias gariepinus). Five isonitrogenous (40% crude protein) and isolipidic (8% ether extracts) feeds were formulated to replace 0% (control), 25%, 50%, 75% and 100% fishmeal with black soldier fly larvae meal. A Randomized Complete Block Design was used and 600 fingerlings (0.46±0.02g) were randomly selected and stocked at a density of 40 fingerlings in 15 circular plastic tanks in triplicates. Fish were fed twice a day at 6% body weight. Results showed that the treatment diets significantly (p<0.05) affected the growth performance indices, feed intake and utilisation indices, and carcass composition of the fish. Furthermore, 25% fishmeal could be replaced by black soldier fly larvae meal without significantly reducing feed intake, feed utilisation efficiency indices and growth indexes. There was no evidence of significant variations in water quality between treatments (p>0.05). A decreased concentration of crude protein, ash, nitrogen free extracts in carcass composition of fingerlings with a corresponding increase in dietary black soldier fly larvae meal inclusion, was observed. Increasing inclusion levels of black soldier fly larvae and decreasing levels of fishmeal, increased concentration of ether extracts and fibre contents of the body composition. Results also showed that feeding the African catfish fingerlings with black soldier fly larvae-based diets reduced significantly (p>0.05) the incidence cost compared to those fed on black soldier fly larvae 0%. From the results black soldier fly larvae 0% had the highest incidence cost (KES 99.99) while black soldier fly larvae 100% (KES 59.93) had the lowest incident cost. Black soldier fly larvae-based diets significantly increased (p<0.05) the profit index compared to those fed on black soldier fly larvae 0% and black soldier fly larvae 100% and 25% had the highest profit index of (KES 5.06) and (KES 4.28) respectively. The present experiment recommended partially replacement of fishmeal up to 25% in order to improve feed utilization, growth performance, carcass composition, and the profit index and further field trials.