UTTAR PRADESH JOURNAL OF ZOOLOGY

The current study aims to analyse the impact of the sub-lethal concentration of nicotine in surface waters on enzymatical changes in tissues of Labeo rohita fingerlings. The experimental fish Labeo rohita fingerlings were exposed to sub-lethal nicotine concentrations in surface water (0.93 mgL^-1) for 60 days. Tissues (liver, gill and kidney) were harvested at different intervals (15, 30, 45 and 60 days of nicotine exposure) to analyze metabolic enzymes, TBARS and antioxidant enzymes. Further acetylcholinesterase enzyme activity was examined in the brain tissue. The metabolic enzymes such as AST and ALT activities increased significantly (p<0.05). In contrast, ACP and ALP activities declined in nicotine-exposed fish of liver, gill and kidney at every interval than in control fish. The peroxidation marker TBARS activity was significantly reduced, meanwhile the activities of enzymatic antioxidants such as SOD, CAT and GPx and non-enzymatic antioxidant GSH activities declined considerably in sub-lethal concentration nicotine-exposed fish tissues (liver, gill and kidney) when compared to control fish. Further, the activity of AChE also declined in the brain of nicotine-exposed fish than in control fish. The results indicate that exposure to the sub-lethal concentration of nicotine in surface water can cause an imbalance in the activities of metabolic enzymes, TBARS, antioxidant enzymes and AChE in fish.