Growth and physiological indices of hybrid grouper (Epinephelus fuscoguttatus × Epinephelus lanceolatus) fed with black soldier fly larvae meal

Abstract Having fish meal (FM) as the principal protein source in aquafeed is no longer sustainable and economically viable. The market demand for hybrid grouper is on the rise, hence the need for a sustainable alternative protein source in their diets that will help farmers profitably meet the rising demand. This study was conducted to determine the appropriate inclusion levels and effect of black soldier fly larvae meal (BSFLM) on the growth performance, feed utilization, somatic and physiological indices of juvenile hybrid grouper ( Epinephelus fuscoguttatus ߻ × Epinephelus lanceolatus ߼) sized about 115.8 ± 2.19 g for 90 days feeding trial. Four isonitrogenous diets were formulated as 0 (control), 15, 30 and 50% BSFLM protein as a replacement for FM protein. Results have shown that hybrid grouper are able to accept BSFLM replacement with no significant difference noticed in terms of feed intake, survival, feed conversion ratio and protein efficiency rate compared to FM. However, higher weight gain and specific growth rate were found in fish that received BSFLM 30 . Adversely, the lowest performances were observed in fish fed with BSFLM 50 . As for muscle proximate compositions, overall fish fed with BSFLM contained higher protein but low lipid content. The hematocrit and plasma osmolality were not significantly affected by dietary BSFLM. Based on the results obtained, this study concluded that the optimum BSFLM inclusion level for juvenile hybrid grouper is between 21-24% for optimum performances.