WATER-BORNE CADMIUM AFFECTS THE GENOTOXICITY, OXIDATIVE STRESS, AND HISTOPATHOLOGY OF THE LIVER OF THE FRESHWATER NILE TILAPIA, OREOCHROMIS NILOTICUS (LINNAEUS, 1758)A.S. Vijayasree1, Sumayya Jafar2 and Akheena Franklin3Abstract Heavy metal contamination of water poses a grave threat to aquatic organisms, including fish. One such heavy element that is harmful to fish is cadmium. The objective of the current investigation was to evaluate the liver of Oreochromis niloticus after it had been subjected for seven days to 1 mg and 5 mg l-1 of cadmium in water in terms of genotoxicity, oxidative stress, and histological reaction. The Comet test was used to evaluate the genotoxicity in the liver of fish. Seven-day cadmium exposure caused significant (P <0.05) DNA damage in fish. Increased lipid peroxidation, superoxide dismutase, and catalase leads to oxidative stress in fish liver, which induces antioxidant defence mechanisms. Inhibitory effect of reduced glutathione and glutathione peroxidase were useful indicators of oxidative stress. The study examined the antioxidant response and oxidative stress biomarkers of the commercially significant fish species, O.niloticus. The decrease in protein content may be attributed to decreased protein synthesis during toxicity. The liver histopathology of affected fish was significantly altered, indicating the quality of the fish stocks. This has severe repercussions for humans, as these fish are consumed by the local population. The results of this study can be used to evaluate the stress that pollution causes in aquatic organisms. O. niloticus with stood the oxidative stress brought on by exposure to heavy metals by using antioxidant defence mechanisms. As a result, Glutathione levels and lipid peroxidation can serve as markers for the presence of heavy metal pollution. |