Evaluating the Inclusion of Black Soldier Fly Larvae in the Practical Diets of African Catfish (Clarias gariepinus)

Abstract

Catfish (Clarias gariepinus) is one of the best candidate aquaculture species. Feed is crucial in fish culture, especially in the early stages. Aquaculture production in Africa is marginal mainly due to inefficiencies in the production systems ascribed to a lack of high-quality fish feed, particularly in sub-Saharan countries like Ethiopia. The major fish feed protein ingredient in fish farming in Ethiopia especially in south west Ethiopia is (BM) that is often times consumes for preparation and results in risk of disease. This problem has necessitated a need for exploring alternative less expensive and easily available protein sources such as black soldier fly larvae (BSFL). This study aimed at evaluating the growth rate, feed utilization, survival and proximate compositions of the African catfish (Clarias gariepinus) reared on diets containing BSFL meal in a formulated fish diet at different rates of substitution. Treatment diets were formulated for BSFL meal to substitute formulated basal diet at the rates of 0% (C), 25% (D1), 50% (D2), and 75% (D3). All diets were formulated to meet the nutritional requirements of catfish. The catfish were stocked in eight tanks each measuring 2 by 0.5 meters and each tank held eight pieces of catfish. The experiment was conducted in a completely randomized design with each treatment in duplicates. The performance of the African catfish was determined by recording the weights, lengths and mortality biweekly for two months. Analysis of variance was carried to determine the effects of the treatment diets on the weight gain and carcasses characteristics. Water quality parameters including dissolved oxygen, temperature, and conductivity measured were within the optimum levels recommended for rearing the African catfish. Catfish consuming diets with 50% and 75% BSF larvae meal had the highest growth rates of 0.54g/day and 0.51g/day respectively. However, the growth rates of the African catfish fed on diets with 0% and 25 % BSFL meal were not significantly different (P>0.05). Carcasses of African catfish fed treatment diets with BSFL meal had significantly (P<0.05) higher amounts of crude protein (CP) especially for D2 and D3. Analysis of the carcasses showed that an increase in BSFL meal led to an increase in the crude fat content of the carcasses. The inclusion of BSFL meal did not negatively affect the nutritive composition and carcass quality of the African catfish. Substitution of BSFL meal for formulated basal diet in the treatment diets didn’t negatively affect the survival rates of the catfish. The study recommends the use of BSFL meal at substitution rates of 50% and 75% for better survival and enhanced growth performance of African catfish as well enhanced quality of its carcass.