EFFECTS OF DIETARY TUNA HEAD HYDROLYSATE INCLUSIONS ON GROWTH, FEED UTILISATION AND BODY COMPOSITION OF POMPANO (Trachinotus blochii)

Abstract

This study evaluated the beneficial effects of tuna head hydrolysate (TH) as alternative protein source to fishmeal in diet on growth rate, feed utilization and body composition of juvenile pompano (Trachinotus blochii). Juveniles (4.15 g/fish) was fed to five isonitrogenous (crude protein 45.0 %, lipid 11.0 %) diets with five TH inclusion levels (0; 30; 60; 90 and 120 g/kg) for 56 days. The results indicated that the specific growth rate (SGR) was significantly higher in fish fed diets containing 60 and 90 g/kg TH than those fed other diets. There were no significant effects of TH inclusion on survival rate, hepatosomatic and viscerasomatic indexes of pompano (P > 0.05). The apparent digestibility coefficient (ADC) of protein was significantly improved in the fish fed 60 g/kg TH inclusion diet. Increasing the inclusion levels of TH up to 120 g/kg had no significant effects on crude lipid, moisture and ash contents of the fish, whereas protein content was significantly reduced in fish fed 120 g/kg TH diet (P < 0.05). The muscle amino acids had no significant difference among treatments. Based on the quadratic regression between TH inclusion levels and SGR, the optimum TH in the diet for maximum growth rate of juvenile pompano was estimated at 74.5 g/kg.