The necessity of selenium (Se) in maintaining normal growth and physiological functions have been demonstrated in fish due to its important role as a cofactor in glutathione peroxidase enzyme (GPx), protecting cell membranes against oxidative damage. The deficiency of Se can lead to reduced growth, feed utilisation and health status in farmed fish. | Journal of Fisheries science and Technology No. 4 - 2018 SELENIUM DEFICIENCY, TOXICITY AND ITS REQUIREMENT IN MARINE FISH: A RESEARCH REVIEW Pham Duc Hung¹ Received: ; Revised: ; Accepted: ABSTRACT The necessity of selenium (Se) in maintaining normal growth and physiological functions have been demonstrated in fish due to its important role as a cofactor in glutathione peroxidase enzyme (GPx), protecting cell membranes against oxidative damage. The deficiency of Se can lead to reduced growth, feed utilisation and health status in farmed fish. Whereas fish fed elevated dietary Se levels results in reduced feed utilisation and adverse effects on physiological performance and impaired histology. Dietary Se requirements have been quantified for some marine fish species with varied results, probably due to the differences in bioavailability, sources of Se, protein ingredients as well as the interaction of Se with other nutrients in the diets. Besides, due to the narrow gap between deficiency, optimality and toxicity of Se level, it is imperative to find out the exact dietary Se requirement for any aquatic species. This review summarises the available information regarding dietary Se requirements in marine fish. The effects of Se deficiency and its toxicity in marine fish also are discussed. Keywords: selenium, marine fish, toxicity, requirement I. Introduction The nutritional effects of selenium (Se) have gained attention due to its essential roles in growth and physiological functions (Watanabe et al., 1997). It serves as a cofactor in glutathione peroxidase-catalysed reactions, which are necessary for the conversion of hydrogen peroxide and fatty acid hydroperoxides into water and fatty acid alcohol by using reduced glutathione (GSH), thereby protecting cell membranes against oxidative damage. A deficiency of Se can cause negative effects on growth, feed utilisation and survival in many marine fish such as grouper Epinephelus malabaricus, cobia
