Nutritional attributes of carps fed varying protein levels in supplemental diets under pond polyculture conditions

This study examined the effects of six iso-caloric supplemental diets differing in amounts of protein (22, 24, 26, 28, 30, and 32%) on the fillet composition of rohu (Labeo rohita), catla (Catla catla), mrigal (Cirrhina mrigala), grass carp (Ctenopharyngodon idella) and silver carp (Hypophthalmichthys molitrix) raised in ponds containing natural feed. Control treatment with no supplemental feeding was also included. Mean muscle protein concentrations were significantly lower in fish from control ponds compared to ponds that received supplemental feeding, with 26% and 28% protein diets producing significantly highest muscle protein. Mean muscle lipids of 2.12% were significantly higher in muscles from fish receiving 32% protein diet compared to other treatments. Muscle ash was nearly double in fish from control ponds, where-as muscle carbohydrates were nearly double in fish from ponds receiving 22% protein diets. Among five fish species sampled, percent muscle protein was highest in rohu and lowest in silver carp, with all other species having intermediate values. Muscle lipid was greatest in grass carp and lowest in catla. Mrigal and silver carp had greatest muscle carbohydrate, while rohu had lowest. Supplemental feeding of diets with protein ranging from 26 to 28% is recommended during polyculture of cyprinids in ponds.