Effects of hypoxia and dietary vitamin E on growth performance and oxidative status of Cirrhinus mrigala (Ham., 1822)

Abstract

Vitamin E is of importance for several physiological processes, some of which also apply to fish. Here, we conducted an experiment to assess the effect of environmental hypoxia and dietary vitamin E on oxidative status and tissue injury in a bottom dwelling carp,Cirrhinus mrigala(Ham., 1822). The four treatments combined oxygen availability (Normoxia/Hypoxua) and Vitamin E presence/absence. Lipid peroxidation parameters such as thiobarbituric acid reactive substances (TBAR), peroxide value (PV), polyunsaturated fatty acids/saturated fatty acid (PUFA/SFA) ratio, catalase (CAT), superoxide dismutase (SOD) and erythrocyte fragility were assessed. The results indicate that exposure to hypoxia elevates these parameters. However, the supplementation of vitamin E via the diet effectively reduced erythrocyte membrane damage (EF) and myeloperoxidase activity (MPO), which were enhanced by the exposure to hypoxia. Dietary vitamin E also improved antioxidant enzyme status in the hypoxia exposed fish, as indicated by the decreased catalase and superoxide dismutase activities. Vitamin E supplementation also compensated for increased levels of peroxide value, thiobarbituric acid reactive substances, and an increased polyunsaturated fatty acids/saturated fatty acid ratio resulting from the exposure to hypoxia. Overall, it can be concluded that fortification of vitamin E in the diet of this carp species, and possibly other fish that live under hypoxic conditions, can restore the antioxidant status and well-being to some extent.