Ten isonitrogenous and isocaloric diets containing different percentages by weight of cottonseed ineal or gossypol acetate were fed to age‐0 channel catfish Ictalurus punctatus for 8 weeks. Growth was inhibited when fish were fed diets with more than 17.4% cottonseed meal or with 0.09% and greater free gossypol. Fish fed cottonseed meal at 17.4% or greater had higher wholebody concentrations of free gossypol than fish fed lower amounts. Free gossypol in muscle tissue was less than that recommended as safe for human consumption. Free gossypol was most concentrated in liver and kidney tissue. Channel catfish utilized lysine hydrochloride when a diet was supplemented with that amino acid.

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Juvenile freshwater prawns Mucrobruchium rosenkrgii (mean wet weight = 0.75, 1986 or 0.17g, 1985) were stocked into 0.06–0.07 ha earthen ponds at densities ranging from 39,536 to 118,608/ha during two separate growing seasons. After growout periods ranging from 135 to 142 days, survival was from 54.3% to 89.9% (x = 77.0%). Mean prawn weight at harvest ranged from 15.0 to 44.3g and decreased with increasing stocking density. The larger stocking weight of prawns was associated with harvest weights that were 16.8 to 39.6% greater than those achieved with the smaller stocking weight at comparable stocking densities. Stocking of juveniles of the proper size and the effective management of the social structure of M. rosenkrgii appear to be critical to the success of intensive pond culture in temperate climates where the length of the growing season is restricted.

Channel catfish Ictalurus punctatus were reared for 2 years on practical feeds with and without a topdressing of oil (50% animal, 50% vegetable). Visceral fat, fillet fat, and whole‐body protein increased and moisture percentage decreased as fish size and age increased. Slopes of regression lines for these variables differed significantly between treatments. Fatty acid profiles of fillets showed essentially linear trends toward decreasing saturation and increasing unsaturation with increasing size and age of fish. Within the unsaturated fatty acids, monene levels increased, and diene and triene levels decreased. Topdressing with oil did not affect these trends. Although dietary lipid composition is a major influence on fatty acid composition in channel catfish, this study indicates that fish size and age also significantly influence fatty acid profiles.

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