a random block experiment 4×4 with sixteen diets containing four level of protein (35, 40, 45 and 50%) at four carbohydrate to lipid level (1.7, 1.4, .1 and 0.8 ) were designed to research about the ability of utilization of different levels of protein and carbohydrate to lipid ratios diet for juvenile huso huso ( 5.4 ± 0.2, mean sd )in fourteen weeks. fish fed 2-3% of body weight at each day. ...