Can shrimp hydrolysate improve the efficacy of meat and bone meal diet in juvenile giant trevally Caranx ignobilis?

Abstract

A six-treatment study in a 3 × 2 factorial design was conducted to investigate whether dietary supplementation of shrimp hydrolysate (SH) improves the efficacy of meat and bone meal (MBM) replacing fishmeal protein in juvenile giant trevally Caranx ignobilis. A fishmeal-based diet (MBM0) was used as a control; two low fishmeal diets were prepared by replacing 25% (MBM25) and 50% (MBM50) of fishmeal protein with MBM; and another three treatments by supplementing MBM0, MBM25, and MBM50 with 45-g/kg SH supplementation (MBM0SH, MBM25SH, MBM50SH) were produced. The results showed that fish fed MBM25 and MBM50 caused lower growth and feed utilization than MBM0, whereas no differences were observed among fish fed MBM25SH, MBM50SH, and MBM0. Increasing dietary MBM levels resulted in decreased lipids in fish muscles and increased ash contents, while SH supplementation improved the muscle lipid levels. Substituting fishmeal with MBM increased monounsaturated fatty acids (MUFA) and decreased polyunsaturated fatty acids (PUFA), n-3 polyunsaturated fatty acid (n-3 PUFA), n-3 highly unsaturated fatty acids (n-3 HUFA), and n-3/n-6 HUFA, whereas SH supplementation enhanced n-3 PUFA, n-3 HUFA, and n-3/n-6 HUFA. The goblet cell density in the intestine increased in fish fed diets supplemented with SH. The study suggested that dietary supplementation of 45-g/kg SH increased the efficacy of substituting MBM protein for 50% of fishmeal protein without compromising the growth of juvenile giant trevally.