Alternative sources of fish oil (FO) are one of the major problems in aquaculture; therefore, the goal of the present study was to examine insect (black soldier fly larvae) oil (BSLO) as a potential replacer of fish/soy oil in juvenile rainbow trout (initial average weight of 32 ± 0.15 g) feed. Four diets were formulated wherein FO (control diet) was completely replaced with either soybean oil (SO) or BSLO, and an additional BSLO-based diet supplemented with 1.5% bile acid (BSLO + BA) were fed to the fish for 10 weeks. Growth performance of the BSLO fed group was similar (P > 0.05) to that of the FO and SO fed groups, however, the fish fed BSLO + BA diet registered the lowest growth (P < 0.05). Oil sources did not (P > 0.05) affect the major nutrient content of whole-body, however, the fatty acid composition of the muscle and liver was influenced (P < 0.05), with the highest 14:0, 16:0, and total saturated fatty acid detected in BSLO or BSLO + BA fed trout compared to the others (P < 0.001). No significant differences were observed in eicosapentaenoic acid + docosahexaenoic acid (EPA + DHA) or total n-3 polyunsaturated fatty acid (PUFA) content in muscle among the groups, whereas, the highest EPA:DHA and n-3:n-6 ratios were detected in the FO group. Gene expression for fatty acid binding protein (fabp), fatty acid synthase (fas), and Δ5 desaturase in the liver was lower in FO (P < 0.05), while BSLO + BA registered the highest Δ6 expression (P = 0.006). Supplementation of BA in the BSLO diet increased superoxide dismutase (SOD) and catalase (CAT) activities compared to the other groups (P < 0.05). In conclusion, BSLO could serve as a substitute for FO and SO in rainbow trout diet without negatively impacting growth performance, whole-body composition and nutrient retention, and modulate the expression of fatty acid metabolism-related genes in rainbow trout.

鱼油 (FO) 的替代来源是水产养殖中的主要问题之一；因此，本研究的目的是检查昆虫（黑水虻幼虫）油 (BSLO) 作为鱼/豆油幼鱼（初始平均重量为 32 ± 0.15 克）饲料的潜在替代品。配制了四种日粮，其中 FO（对照日粮）完全被大豆油 (SO) 或 BSLO 替代，另外一种基于 BSLO 的日粮补充了 1.5% 胆汁酸 (BSLO + BA)，持续 10 周。BSLO 饲喂组的生长性能 与 FO 和 SO 饲喂组相似（P > 0.05），然而，饲喂 BSLO + BA 饮食的鱼的生长性能最低（P  < 0.05）。油源没有（P > 0.05) 影响全身的主要营养成分，但对肌肉和肝脏的脂肪酸组成有影响（P  < 0.05），其中以 14:0、16:0 和总饱和脂肪酸含量最高与其他人相比，BSLO 或 BSLO + BA 喂养的鳟鱼（P  < 0.001）。组间肌肉中的二十碳五烯酸 + 二十二碳六烯酸 (EPA + DHA) 或总 n-3 多不饱和脂肪酸 (PUFA) 含量没有显着差异，而最高的 EPA:DHA 和 n-3:n-6 比率在 FO 组中检测到。脂肪酸结合蛋白基因表达（FABP），脂肪酸合酶（FAS），以及Δ5去饱和酶在肝中的FO较低（P < 0.05），而 BSLO + BA 记录了最高的 Δ6 表达（P  = 0.006）。与其他组相比，在 BSLO 饮食中补充 BA 增加了超氧化物歧化酶 (SOD) 和过氧化氢酶 (CAT) 的活性（P  < 0.05）。总之，BSLO 可以作为虹鳟鱼饲料中 FO 和 SO 的替代品，而不会对生长性能、全身成分和营养保留产生负面影响，并可以调节虹鳟鱼中脂肪酸代谢相关基因的表达。