The effect of different level of diet containing kaolin on growth performances and biochemical composition of Caspian kutum (Rutililus frissi kutum, Kamenskii, 1901)

Some supplements like kaolin accelerate growth and survival of animals; hence this additive was trialed on Rutililus frissi kutum. Six-hundred advanced fry fishes with average weight of (0.7 ± 0.062 g) were randomly distributed between 15 tanks of 500 L capacity. Five diets containing 0.5, 1, 1.5, 2 and 2.5 % kaolin with iso-nitrogenous (35%) in triplicate group were considered. With increasing kaolin to 2%, growth and food efficiency were improved and was significant with other treatments (P< 0.05).Treatments 1 and 5 (0.5 and 2.5 percent) with minimum and maximum levels of kaolin were shown unimprovement in growth performances (P<0.05). Carcass chemical compositions of kaolin in different levels were not shown any significant different among treatments; however with increasing kaolin to 2 and 2.5%, total ash contents were increased (P< 0.05).