Pond Production and Fatty Acid Profiles of the Fillets of Channel Catfish Reared on Diets with Different Protein Sources

Abstract

AbstractThree protein sources were evaluated as supplements to grow‐out feeds for mixed‐sized channel catfish Ictalurus punctatus stocked at 16,750 fish/ha in 0.04‐ha earthen ponds. Three practical diets were tested: (1) meat, bone, and blood meal (MBM), (2) fish meal containing menhaden Brevoortia spp., and (3) soybean meal and wheat (lysine added). The fish were fed to satiation once daily for 133 d. For total fish harvested, dietary protein did not affect the weight gain, hepatosomatic index, percent survival, harvest yield, protein efficiency ratio, percentage of intraperitoneal fat, or dress‐out percentage. Feed consumption and the feed conversion ratio were significantly higher in fish fed the MBM diet. This diet also produced a significantly lower percentage of lipids in the fillets. Significant differences were shown for fatty acids found in the fillets of large fish and small fish fed all diets. A size‐related significant difference was found for the total saturated fatty acids, where values for the fillets of small fish were lower than those of large fish. Conversely, a size‐related significant difference was found for the total monounsaturated fatty acids in the fillets, where the large fish had lower levels than those of the small fish. When the fatty acids found in the fillets were classified as total polyunsaturated fatty acids (total omega‐3 fatty acids or total omega‐6 fatty acids), no significant differences in concentrations as a result of diet were found. This suggests that all three protein sources performed similarly and that the all‐vegetable diet supplemented with lysine is a suitable alternative to diets containing animal and fish protein sources for channel catfish grown under pond production conditions.