Influence of Stress and Dietary Natural‐Source Vitamin E on Nonspecific Immunocompetence, Tissue Tocopherol Composition, and Postslaughter Fillet Oxidative Stability in Sunshine Bass

Abstract

AbstractWe evaluated the effects of stressor exposure and super‐requirement levels of RRR‐α‐tocopheryl acetate (natural‐source vitamin E [NSVE]) on production performance and nonspecific immunocompetency of juvenile sunshine bass (female white bass Morone chrysops × male striped bass M. saxatilis). Stressor exposure elicited physiological changes consistent with the generalized stress response, and the magnitude of responses generally mirrored stressor severity. Stressor exposure resulted in lower fillet peroxides and greater aldehydes after short‐term frozen storage, whereas increasing dietary NSVE was associated with a nonsignificant reduction in aldehydes after long‐term storage. Fillet α‐tocopherol content increased linearly with dietary NSVE, exceeding reported tissue levels achieved with synthetic vitamin E (SYNE). Although we observed no significant immunological effects of stress or dietary NSVE content, sampling time and high individual‐to‐individual variation probably restricted our ability to resolve statistical significance. Similar results of vitamin E supplementation have previously been reported; however, the effective dietary concentrations we observed for NSVE are low in comparison with values reported for SYNE. The potential of RRR‐α‐tocopheryl acetate as a highly active vitamin E source for aquaculture feeds warrants further evaluation of the relative suitability of NSVE in meeting the demands of optimal aquaculture nutrition.