Shwetha Alavandi and B. B. Hosetti
This study was undertaken to evaluate the catalase activity in two Indian major carps Catla catla and Cirrhinus mrigala. Fishes were exposed to sublethal concentration (0.07 mg/l and 0.115 mg/l) of cyanide and the effect of cyanide on the catalase (CAT) activity was assessed in liver, brain and gill tissues of the fish on day 7 and day 14 of exposure. Among the tissues, brain exhibited maximum decrease in the catalase activity followed by gill and liver. The change was more pronounced on day14 of exposure. Inhibition in the activity of CAT was more pronounced in C. catla. This indicates that sublethal concentration of cyanide can cause changes in activity of key enzyme, the catalase. Results indicate that cyanide is a potential toxicant induces oxidative stress and may bring serious potential health risk. The investigated parameter can be used as biomarker of cyanide toxicity in the freshwater fish
