Effect of dietary vitamin E on rainbow trout (salmo gairdneri). Muscle alpha-tocopherol and storage stability.

An experiment was conducted to study the effect of dietary vitamin E (basal alpha-tocopherol plus supplemental DL-alpha-tocopheryl acetate) on the muscle alpha-tocopherol levels in rainbow trout. The relationship of muscle alpha-tocopherol and its storage stability were measured by changes in thiobarbituric acid number (TBA) between one year frozen storage (-17 degrees C) and one year frozen (-17 degrees C) plus 7 days' refrigeration (2 degrees C). The alpha-tocopherol content in the muscle of fish fed the experimental diets for 24 weeks was significantly (p less than 0.05) increased only by a very high level of dietary vitamin E. Changes in TBA between frozen and frozen-refrigerated storage were not significantly (p less than 0.05) affected by the dietary treatments. The expected improvement of storage stability in muscle of fish fed high dietary vitamin E was not observed. These data suggest that the response of muscle alpha-tocopherol to dietary vitamin E was too low to be economically feasible while a large amount of dietary vitamin E was deposited in the liver which is normally discarded during processing.