Antioxidant role of zinc and calcium supplementation against cadmium induced oxidative stress in fresh water teleost oreochromis mossambicus (tilapia)

Cadmium (Cd) has the ability to accumulate in the tissues and disturb antioxidant defense system. In the present study, Fishes were exposed to 1/10th of LC50 / 48 hr. of Cd for 7, 15 and 30days to know the antioxidant role of zinc and calcium on cadmium toxicity. After 15d Cd exposure, fish were divided into three groups. 1st group was supplemented with Zinc (1 ppm), 2nd group received Calcium (1ppm) and 3rd group was supplemented with combination of both zinc and calcium at the above said doses for 7, 15 and 30days. After specific time intervals fish were sacrificed and selected tissues such as liver, kidney, brain, gill and muscle were isolated for the assay of oxidative stress enzymes like superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST) and glutathione peroxidase (GPx). Simultaneously lipid peroxidation (LPO) levels were also measured. A significant elevation in LPO levels with decreased activity levels of CAT, SOD, GPx and GST were observed during Cd exposure. With zinc and calcium supplementation, a significant reversal in the activity levels of above said enzymes was observed. Our findings clearly envisage that the zinc and / or calcium supplementation is very effective in reducing the Cd toxicity.