Effects of black soldier fly oil rich in n-3 HUFA on growth performance, metabolism and health response of juvenile mirror carp (Cyprinus carpio var. specularis)

Abstract

In the present study, we aimed to assess the effect of dietary black soldier fly oil (BSFO) enriched with n-3 highly unsaturated fatty acids (HUFA) on growth performance, lipid metabolism, inflammation and related gene expression in juvenile mirror carp (Cyprinus carpio var. Specularis). Triplicate cages of juvenile mirror carp were fed one of five isonitrogenous and isolipidic diets for 8 weeks. The control diet contained 25 g kg−1 soybean oil (SO), which was 25%, 50%, 75% or 100% replaced with an n-3HUFA enriched BSFO. This enrichment was done by growing the insects on a by-product of microalgae oil production. The growth and nutrient utilization as well as many health parameters of the fish were significantly improved when fed a 50% or higher replacement of SO with the n-3 HUFA enriched BSFO. A replacement level at 50% or above led to a decreased intra-peritoneal fat index and adipocyte size, accompanied by relevant changes in gene expression. The same replacement levels also led to an improvement in the serum biochemical profile of the fish and showed indications of enhancing immune status. Gene expression results of the liver and head kidney indicates a less inflammatory state in fish fed more than a 50% replacement of SO with BSFO. Overall, this study showed that a 50–100% replacement of SO with this n-3 enriched BSFO positively influences the performance and health status of juvenile mirror carp.