Effect of untreated sewage water on antioxidant enzymes of fish Labeo rohita

Abstract

The unregulated discharge of untreated municipal sewage water to the natural water bodies is a major threat to the aquatic ecosystems. In the present study, the fingerlings of Labeo rohita were exposed to treated sewage water and 1/10th of LC50 and 1/20th of LC50 of untreated sewage water (UT) obtained from sewage water treatment plant, Ludhiana, India. After determining 96 hr LC50 value of UT, fingerlings were divided into four groups: control, treated, 1/10th of LC50 and 1/20th of LC50 UT and exposed for the period of two months. The oxidative stress parameters viz. proteins, lipid peroxidation (LPO), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S- transferase (GST) were examined in the liver of fingerlings. Results of this study revealed a significant decrease (p≤0.05) in the levels of proteins and the activity of SOD and GPx in 1/10th LC50 and 1/20th LC50 UT groups, however, the activity of LPO, CAT, GR and GST was found to increase significantly (p≤0.05) in 1/10th LC50 and 1/20th LC50 UT groups in comparison to control and treated group. Hence, the study concluded that untreated sewage water has a potential to alter the activity of antioxidant enzymes in liver, however, clean and treated water can restore the activity of these enzymes in fish.