Effect of Cdless thansupgreater than++less than/supgreater than On Catalase Activity on Air Breathing Fresh Water Teleost Fish Heteropneustes fossilis (Bloch)

The objective of this study is to determine the effect of Cadmium (a heavy metal) on Catalase activity on tissues of liver, kidney and gill of freshwater air breathing Teleost fish (Heteropneustes fossilis). Catalase, a oxido-reductase enzyme play an important role in anti-oxidant defence System which protect animal from oxidative stress. Heteropneustes fossilis (Bloch), a medicinally important fresh water fish were exposed for 96 hours at different concentrations 0.1 mg/itr, 0.5 mg/ltr and 1.0 mg/ltr of Cd and observed its effects on liver, kidney, and gill tissues. Cd has shown increased CAT activity in all the tissues studied. It has also been observed that highest increase of the CAT activity in liver, exposed to 1.0 mg Cd/ltr. On the other side Cd had no significant effect in gill. The result of these studies in fish tissues may prove that CAT enzyme could be used as a sensitive bioindicator of the antioxidant defense system.