Effects of dietary hydrolysate supplementation on growth, body composition, hematological responses, and liver histology of juvenile giant trevally (Caranx ignobilis Forsskal, 1775)

Abstract

A feeding study was conducted to investigate how fish protein hydrolysate (FPH) supplementation affected the growth, feed utilisation, body composition and haematology of juvenile giant trevally (Caranx ignobilis Forsskal, 1775). Seven isonitrogenous (52% protein) and isocaloric diets (10% lipid) were formulated, wherein shrimp hydrolysate (SH) and tuna hydrolysate (TH) were used to replace fishmeal at inclusion levels of 0 (control), 30, 60 and 90 g/kg and labelled as control, SH30, SH60, SH90, TH30, TH60, TH90 respectively. Each diet was fed to triplicate groups of juvenile giant trevally for eight weeks. The results showed higher final body weight and specific growth rate in fish fed SH30, SH60, TH30 and TH60 than fed control diet. No difference was observed in feed intake, however, reduced FCR was found in fish fed SH30, SH60, TH30, and TH60, demonstrating these diets improved feed utilisation. TH90 caused deposition of lipid droplet in the hepatocyte, a sign of liver damage. While total MUFA, PUFA, and HUFA in fish were not affected by FPH supplementation. Fish fed TH30 showed lower ∑n‐3 PUFA than the fish fed remaining dietary treatments. The elevated serum protein was seen in fish fed control, SH30, SH60, and TH30, demonstrating that these diets were beneficial for the innate immune response in giant trevally. The results indicated that TH and SH could be incorporated into diets of giant trevally at 30‐60 g/kg, replacing 7‐13% fishmeal with enhanced growth and health benefits.This article is protected by copyright. All rights reserved.