Influence of black soldier fly (Hermetia illucens) larvae oil on growth performance, body composition, tissue fatty acid composition and lipid deposition in juvenile Jian carp (Cyprinus carpio var. Jian)

Black soldier fly larvae oil (BSO) is a potential fat source in aquaculture feeds, which is high in lauric acid (21.4%–49.3%). In order to investigate the effects of dietary BSO on growth performance, fatty acid composition and lipid deposition in juvenile Jian carp (Cyprinus carpio var. Jian), five experimental diets were formulated by substitution of 0%, 25%, 50%, 75% and 100% soybean oil (SO) with BSO. Total 300 Jian carp (10.67±0.80g) were divided randomly into 5 groups (triplicate per group) and was fed with the diets above respectively). After 59days feeding growth, fatty acid composition and lipid deposition was determined. The results showed that growth, nutritive utilization and serum biochemical parameters of fish in five groups were not different (P>0.05). Fatty acid composition in the intraperitoneal fat tissue, muscle and hepatopancreas was closely correlated with diets. While, the 22:6n-3 content of treated groups was significantly higher than that of the control group (P<0.05) in the muscle. Intraperitoneal fat index and the size of adipocyte in intraperitoneal fat decreased in higher BSO intake compared with SO group (P<0.05). Relative gene expression of PPARα significantly increased (P<0.05), while PPARγ and FAS was not significantly affected by dietary BSO level (P>0.05). The Bcl-2/Bax ratios were not different among five groups (P>0.05). These results suggested that the growth of Jian carp was not affected by dietary BSO, while it decreased lipid deposition in the intraperitoneal fat tissue of Jian carp by higher gene expression of PPARα.Previous studies on nutrition of fish have highlighted the importance of fish oil. However, with the worldwide decreasing supplies as well as the escalating prices of this ingredient, alternative resources were sought and nutritionally evaluated. Plant or vegetable oils are now introduced in fish diets, but these sources have limitations, such as palatability and production issues. In the recent years, insects have received wide attention as a potential source of lipid, especially black soldier fly. Black soldier fly grow and reproduce easily, have high feed conversion efficiency and can be reared on biowastes. Insects often accumulate fat, especially during their immature stages. The lipid content of non-defatted black soldier fly larvae is highly (26%–35%). This study was designed to explore the possibility that black soldier fly larvae oil as a lipid resource in aquafeeds, and to determine its effect on growth performance, feed utilization efficiency, major nutrients composition, fatty acid composition and lipid deposition.