Abstract:This study was conducted to evaluate the effects of replacement of fish meal (FM) by defatted black soldier fly larvae meal (DBSFLM) on growth, body composition, serum biochemical parameters, and antioxidant capacity of juvenile large yellow croakers (). Six isonitrogenous (45% crude protein) and isolipidic (10% crude lipid) diets were formulated by replacing 0, 20%, 40%, 60%, 80%, and 100% of FM protein with DBSFLM (named as G0, G20, G40, G60, G80, and G100, respectively). A total of 2160 juvenile large yellow croakers with an initial body weight of (50.08±3.31) g were randomly divided into six groups with three replicates, and 120 individuals for each replicate. Fish were reared in an indoor cement tank (2 m×1 m×1 m) and were hand-fed each diet to apparent satiation twice daily for 7 weeks. The results showed that survival rate of G100 was significantly lower than the other experimental groups (<0.05). Weight gain rates, specific growth rate, and protein efficiency ratio in the G40 group were all significantly higher than those in the other groups (<0.05). The muscle crude protein content decreased as the DBSFLM replacement level was increased, particularly when the replacement level exceeded 40% (<0.05). Crude lipid and crude ash content significantly increased when replacement level reached over 60% (<0.05). The activity of serum ALT and AST significantly increased, and serum TG and cholesterol levels significantly decreased with the increase of the replacement level (<0.05). Total antioxidant capacity (T-AOC) of fish liver in the G20 group and superoxide dismutase activity (SOD) in the G40 group were the highest among all groups. The lowest liver malondialdehyde (MDA) content was found in the G40 group. The catalase (CAT) activity decreased and was significantly lower when replacement level exceeded 40% (<0.05). In conclusion, up to 40% of DBSFLM may successfully replace FM in diets for juvenile large yellow croakers, without adverse effects on growth performance, body composition, and health status.