Effects of silkworm pupae powder on growth performance, muscle fatty acid composition, and intestinal function in mandarin fish (Siniperca chuatsi)

This study examined the effects of dietary silkworm pupae powder (SWP) supplementation on the growth performance, muscle fatty acid composition, and intestinal function in mandarin fish (Siniperca chuatsi) during a 60-day feeding trial. A total of 360 fish (initial body weight 52.44 ± 0.06 g) were distributed randomly into three groups with three replicates per group and 40 fish per replicate. The three groups were fed either the basal diet, supplementation with 1.0 % fermented SWP (T1), or supplementation with 1.0 % fermented induced SWP (T2, induced by Beauveria bassiana). Results showed that fish fed T1 had significantly higher (P < 0.05) condition factor, C16:0, C20:4n-6, C20:5 n3, C22:6n3 C22:5n6, C22:5n-3, and n-3/n-6 levels, but lower (P < 0.05) fat body ratio, C18:1, C18:2n-6 and crude lipid levels than those fish fed basal diet. All fish had similar (P > 0.05) weight gain rate, specific growth rate, feed conversion rate, feed intake, and hepatosomatic index. Fish fed T2 had higher (P < 0.05) trypsin activity than those fish fed basal diet. Compared with the basal diet, fish fed T1 or T2 had higher (P < 0.05) villus length, muscular layer thickness, glutathione peroxidase, alkaline phosphatase, and lysozyme activities, but lower (P < 0.05) triglyceride and total cholesterol levels. Comparative transcriptomic analysis indicated that T1 or T2 enhanced immunity and lipid metabolism ability, as manifested in the up-regulated expression of il12rb1, scdb, tlr2, and FABP7, and the down-regulated expression of EBP and hsd17b7. These findings suggest that dietary supplementation with fermented SWP could enhance the health and quality of mandarin fish, potentially offering a valuable strategy for improving aquaculture productivity.