Efficacy of reduced protein diets and the effects of indispensable amino acid supplements for Nile tilapia Oreochromis niloticus

•The study was conducted to evaluate the performance of Nile tilapia fed graded levels of protein with or without IAA supplemented in practical diet.•Ideal protein concept can be applied in formulating the diets for Nile tilapia to optimize AA profile of the diets.•Well-balanced IAA profile can be used to reduce the intact protein levels of feed (32 to 27.2 %) without causing impaired growth of fish.