Effect of Dietary Protein Level on Growth and Body Composition of Juveniles Nile Perch (Lates niloticus, Linnaeus 1758)

Abstract

Nile perch (Lates niloticus, Linnaeus, 1758), is a carnivorous fresh water fish that have good market demand and suitable for aquaculture. The present study was designed to determine the effect of dietary protein level on growth and body composition of juveniles Nile perch. Five experimental diets with increasing levels of protein (30, 35, 40, 45 and 50 g crude protein 100 g^-1 feed) were prepared and fed in duplicate groups of Nile perch (initial weight : 8.67±0.17 g) reared in ten 50 L tank for 8 weeks. Results showed that dietary protein level significantly influenced weight gain, specific growth rate and feed conversion ratio. The WG and SGR increased with increasing the protein level up to 45% content. Feed conversion ratio was lowest in Nile perch fed 45% protein and highest in those fed 30% protein. Fish fed with the 30% protein diet had the lowest survival and those fed 50% protein diet had the highest survival. There was no significant difference (P>0.05) in Moisture among the dietary treatments. Protein and lipid showed linear increase as dietary protein levels increased. Fish fed diet ≥ 45% protein had the highest protein content, followed by fish fed 30 to 40% protein and lowest in the initial fish. Fish fed diet containing 50% protein had the highest lipid carcass content, whereas the lowest lipid content among treatment was observed in the initial fish. Under the experimental conditions applied, juvenile L. niloticus, require 45% dietary protein for optimized growth.