Utilization of various dietary carbohydrate levels by the freshwater catfish Mystus montanus (Jerdon)

In order to determine the effect of different levels of carbohydrate in artificial diets on growth and feed conversion of freshwater catfish Mystus montanus, six diets with gradual levels of carbohydrates (2%, 5%, 7%, 9%, 12% and 14%) were prepared in pelleted form and fed to the fingerlings of M. montanus to evaluate changes in growth and feed conversion. Higher survival (89%) and specific growth rate (1.06% d^-1) as well as better feed conversion ratio (1.04) were observed in fish receiving diet a containing 9% carbohydrate level. The growth performance of fish fed different carbohydrate diet levels was statistically significant at P<0.05 level. The carbohydrate dietary level did not significantly influence the carcass moisture, dry matter, biochemical composition and ash. The dietary nutrient levels were not influenced on the carcass composition, because fish fed a low dietary protein (diet C₄; 42% dietary protein) had a high carcass protein (68.8%), but fish fed a high dietary protein (diet C₅; 43% dietary protein) had a low carcass protein (67.2%). The results of the present investigation indicated that the optimum requirements of 9.48% carbohydrate are recommended for better growth of M. montanus.