TOXICOLOGICAL EFFECTS OF TERTIARY MIXTURE OF METALS ON THE OXIDATIVE STRESS IN CIRRHINA MRIGALA AND LABEO ROHITA

Present research work was conducted to measure the effects of tertiary metals mixture (Fe+Zn+Mn) on superoxide dismutase (SOD) activity in various tissues of two major carps, Cirrhina mrigala and Labeo rohita at controlled laboratory conditions. 90-day-old fingerlings of both fish species were exposed to 1/4th and 1/5th of their respective 96-hr LC50 value of Fe+Zn+Mn mixture, for 24 days. After 6, 12, 18, and 24-day exposure, fish from each treatment will be sampled, dissected and their tissues viz. brain, gills, kidney, and heart isolated for the SOD enzyme assay. The physical and chemical parameters of test media viz. pH, temperature, dissolved oxygen, total hardness, carbon dioxide, total ammonia, magnesium, and calcium were determined on a 12-hourly basis. It was observed that with an increase in metal concentration, the activity of enzymes increased significantly in both fish species which was maximum at 1/4th of LC50 with the mean value of 49.35±10.04 UmL-1 in C. mrigala. In Labeo rohita, SOD activity decreased with an increase in exposure duration. SOD activity was maximum on day 6 at 52.22±12.91 UmL-1, and on day 24, it was minimum at 35.01±6.91 UmL-1. Among the organs, the SOD activity followed the trend: gills > heart > kidney > brain. The various tissues of metals mixture treated fish Cirrhina mrigala showed significantly increased activity of SOD in comparison to Labeo rohita. All the physicochemical parameters varied significantly at p<0.05 during this study period.