Influence of Fish Size, Origin, and Stress on Ascorbate Concentration in Vital Tissues of Hatchery Rainbow Trout

Abstract

Abstract One-year-old rainbow trout (Oncorhynchus mykiss of probable steelhead origin) were analyzed for total ascorbate and dehydroascorbate concentrations before stocking and after transportation stress. Fish were reared on practical diets containing 0–60 mg total ascorbate per kilogram in state hatcheries in Ohio and New York. We concentrated on the influence of origin, fish size, and stress of short duration on ascorbate status in vital tissues. Liver ascorbate concentrations varied significantly between hatcheries – 78.9 ± 15.6 μg/g at Altmar, New York, and 123.6 ± 32.7 μg/g at London, Ohio – and were highly correlated with fish size (r = –0.572,N= 57). In fish subjected to hauling stress, liver and kidney ascorbate increased, whereas the dehydroascorbate decreased significantly if the fish size variable was included in the analysis. The livers, kidneys, and intestines of rainbow trout reared under practical hatchery conditions showed moderate levels of ascorbate compared with organs of fish experime...