Abstract
Black soldier fly (Hermetia illucens) larvae are a promising source of insect lipids, characterized by rapid fatty acid accumulation and a high lauric acid content. This study investigated the effects of dietary black soldier fly oil (BSFO) on muscle quality in largemouth bass (Micropterus salmoides). Experimental diets were formulated to be isonitrogenous, isolipidic, and isophosphoric, with 1.0% and 2.0% BSFO partially replacing soybean oil. A control group received 2.3% soybean oil without BSFO or glycerol monolaurate (GML), while positive controls were supplemented with 0.35% and 0.7% GML. Fish (initial weight: 25.08 ± 0.12 g) were cultured in pond cages for 56 days, and three replicates were established for each treatment group. Muscle quality and nutritional traits were evaluated, including proximate composition, fatty acid profiles, texture properties, fiber diameter, hydroxyproline content, antioxidant capacity, and expression of genes related to myogenesis, atrophy, apoptosis, and mTOR signaling. Compared with the control, the 2.0% BSFO group showed a significant increase in muscle hydroxyproline content (p 0.05), but n-3/n-6 polyunsaturated fatty acid (PUFA) ratios and highly unsaturated fatty acid (HUFA) levels were significantly elevated (p 0.05); mTOR signaling pathway-related genes (s6k1 and akt1) were significantly upregulated in the 2.0% BSFO group (p