Evaluation of natural source vitamin E, RRR-alpha-tocopheryl acetate, as an alternative micronutrient source and nutriceutical for sunshine bass Morone chrysops x M. saxatilis culture

In addition to strong economic incentives, public concern regarding the use of chemotherapeutants to control stress-related disease and mortality of aquatic livestock encourages the development of alternative disease management strategies for the aquaculture industry. Certain dietary constituents possess immunostimulative properties and, accordingly, investigation of 'nutriceuticals' is a growing field in aquaculture nutrition. Because of its immunomodulatory function and safety at high dosages, vitamin E is an ideal candidate for nutriceutical application. However, vitamin E exists in a wide variety of chemical and isomeric forms, and the form of the vitamin E used may influence overall nutriceutical potential. Natural source vitamin E (NSVE) is a purified source of the most biologically active form of vitamin E, RRR-alpha-tocopheryl acetate. Although NSVE is purported to be a more effective source of vitamin E, aquafeed manufacturers typically use synthetic vitamin E (SYNE), all-rac-alpha-tocopheryl acetate. The purpose of this dissertation was to evaluate NSVE in terms of (1) its potency in meeting the dietary vitamin E requirement of sunshine bass Morone chrysops x M. saxatilis, (2) its potential as a nutriceutical within the context of sunshine bass culture, and (3) as an alternative to SYNE for aquafeed formulations.; I determined the vitamin E requirement of sunshine bass can be met by 22 mg NSVE kg-1 feed, less than the 28-60 mg kg-1 range reported for synthetic vitamin E. Although no significant effects on stress tolerance were observed, increasing dietary NSVE to roughly five times (5X) the minimum dietary requirement was associated with subtle modulatory influence on nonspecific immunocompetency. Stress was associated with reduced fillet oxidative stability, however, increased dietary provision of NSVE resulted in dramatic increases in fillet tocopherol content and improved post-slaughter stability. I subsequently compared requisite and 5X levels of SYNE and NSVE during disease challenge of sunshine bass. Based on pathogen burden and clinical measures of nonspecific immunity, I conclude, with respect to nonspecific mechanisms of disease resistance, the immunomodulatory influence of NSVE is unique and superior to SYNE. Further, super-requirement dietary levels of NSVE may enhance immunocompetency of sunshine bass during infection and aid in pathogen clearance. Super-requirement levels of NSVE were associated with increased energy mobilization during exertion and physical stress of sunshine bass, potentially via alterations in prostaglandin synthesis. I conclude NSVE is more biologically potent than SYNE in meeting minimum dietary requirements of sunshine bass and, when provided at super-requirement levels, NSVE consistently confers benefit beyond that achieved with SYNE. Given the increased potency and unique characteristics of NSVE, nutriceutical application of this product may result in decreased cost of production and increased product value in sunshine bass culture.