Four artificial diets with dietary protein levels of 20%, 30%, 40% and 50% were prepared and their effects on growth, food conversion ratio (FCR) and protein efficiency ratio (PER) were evaluated for the fry (0.838 g) and young (40.0 g) of O. niloticus. For fry, the best growth was obtained with 40% dietary protein, followed by the diets containing 50%, 30% and 20% protein. Food conversion efficiency increased with increasing protein levels in the diet up to 40% protein, then decreased for the diet containing 50% protein.
Maximum growth of young tilapia was obtained using the diet containing 30% protein. Feed conversion efficiency increased from 20% to 30% dietary protein, and thereafter decreased for diets containing 40% and 50% protein.
The protein efficiency ratio for fry and young tilapia decreased with increasing dietary protein levels.