Arsenic-Induced Antioxidant Enzyme Responses in Catfish, Heteropneustes fossilis

Abstract

Arsenic contamination in groundwater is a significant environmental challenge worldwide,
affecting both developed and developing nations. Aquatic organisms, including
fish, are also severely affected. Arsenic accumulates in fish tissues such as gills, liver,
kidneys, skin, and muscles, causing damage to these vital organs of the fish. In the
present study, changes in the activity of two antioxidant enzymes, i.e., superoxide
dismutase (SOD) and catalase, were measured in the liver of catfish, Heteropneustes
fossilis. The fish were exposed to two sublethal concentrations of dibasic sodium
arsenate heptahydrate: 4.88 mg L−1 and 14.64 mg L−1. Fish were treated for 96
hour and 7 days with both concentrations. The activity of SOD and catalase was
measured by the spectrophotometric method. Our data showed about a 3.5-fold
increase in SOD activity in fish exposed to 4.88 mg L−1 arsenic for 96 hour. No
significant increase was observed in fish exposed to the higher concentration (14.64
mg L−1). Fish exposed to arsenic for 7 days exhibited about 2-fold and 1.4-fold SOD
activity at 4.88 mg L−1 and 14.64 mg L−1, respectively. The catalase assay showed
nearly 2-fold increased activity in fish exposed to arsenic solutions of 4.88 mg L−1
and 14.64 mg L−1 for 96 hour. However, after 7 days of treatment, fish exhibited
only a mild increase in catalase activity (∼ 1.25-fold) compared to the control group.
The findings of the study suggest that SOD and catalase enzyme activity vary with
arsenic concentration and treatment duration in H. fossilis.