Different protein levels and animal protein in diets on the initial development of the African catfish (<em>Clarias gariepinus</em>, Burchell, 1822)

Abstract

The influence of protein contents on initial growth of the African catfish, Clarias gariepinus (Burchell, 1822) was evaluated. Twelve pelleted diets with four levels of crude protein (20, 26, 32 and 38%) and three proportions of protein from animal sources (zero, one quarter and half of total protein level) were used. Experiment was carried out in 36 aquariums in which fingerlings were fed ad libitum twice a day, during two experimental phases consisting of 45 and 30 days. Results revealed that C. gariepinus fingerlings were relatively high-demanding with regard to source and level of crude protein in the diet. Survival rate and performance only improved with an increase in protein level, or rather, when protein of animal origin in diets was highest (50%). Best average values in weigh gain, food intake, food conversion efficiency, protein efficiency rate and specific growth rate, obtained with diets containing 50% of protein from animal origin, occurred with an increase of crude protein to 38%. On the other hand, this diet favored higher heterogeneous development, dominance and a decrease in the survival rate during the initial growth phase.