عنوان مقاله [English]
نویسندگان [English]چکیده [English]
A feeding experiment was conducted in a flow through water system to investigate effects of different dietary protein levels (isocaloric diets) on growth performance and survival of juvenile crayfish (Astacus leptodactylus). Four purified experimental diets with various levels of protein (25,30, and 40%) were formulated and fed to 120 crayfish for 90 days in the individual compartment. The diets which contained 35-40% dietary protein produced the highest values in weight gain (WG), specific growth rate (SGR), and feed utilization (ANPU). Survival of crayfish was not effected by dietary protein levels. The crayfish that were fed on the diet containing 35% protein had significantly higher PER than those which were fed with a diet containing 40% protein. Carcase composition was found to be influenced by food type. The higher protein content resulted in an increase in carcase protein and ash contents while a decrease in carcase in lipid and moisture levels was detected as influenced by the protein content. The results indicate the optimum dietary protein level for crayfish to be in the range35 to 40%.