POSSIBLE DETOXIFICATION ROLE OF ZINC AND SELENIUM SUPPLEMENTATION AGAINST CADMIUM INDUCED BIOACCUMULATION AND OXIDATIVE STRESS IN TELEOSTEAN FISH OREOCHROMIS MOSSAMBICUS

Obaiah Jamakala* and A. Usha Rani

ABSTRACT

Cadmium (Cd) is one of the most common non-essential toxic element, relatively accessible heavy metal in our environment. The present study examines the detoxification role of zinc (Zn) and selenium (Se) against Cd induced bioaccumulation and oxidative stress in fresh water teleost Oreochromis mossambicus. Fish were exposed to sub lethal concentration of Cd (1/10th of LC50/48h) for 7, 15 and 30 days (d) period. 15d Cd exposed fish were considered as control and divided into three groups. The first group of fish were subjected to Zn (1ppm) supplementation, second group received Se (0.5ppm) and third group of fish were supplemented with the combination of both Zn and Se at the above said doses and observed again for 7, 15 and 30d time periods. After specific time intervals, liver, kidney, gill, brain and muscle tissues were isolated and used for the estimation of bioaccumulation levels as well as assay of oxidative stress enzymes like superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST). Simultaneously lipid peroxidation (LPO) levels were also measured. Bioaccumulation levels were significantly increased with the increased period of Cd exposure. After supplementation with Zn and Se, bioaccumulation levels were progressively decreased. A significant elevation in LPO levels with decreased activity levels of CAT, SOD, GST and GPx were observed during Cd intoxication. With Zn and/or Se supplementation, a significant reversal in the above oxidative stress enzymes was observed. The present study reveals that combined supplementation of Zn and Se tends to detoxify the Cd induced alterations in the test tissues than the other modes of supplementation.

Keywords: Cadmium, Bioaccumulation, Oxidative stress, Zinc and selenium, Fish.