Oxidative stress and changes in locomotor behavior and gill morphology of Gambusia affinis exposed to chromium

Sublethal effects of chromium trioxide on mosquito fish, Gambusia affinis, were carried out for 28 days on day 4, 8, 12, 16, 20, 24, and 28. The sublethal effects of chromium (LC₁₀, 77.62?mg?L^?1) on antioxidant enzymes, thiobarbituric acid reactive substance (TBARS), locomotor behavior, and gill morphology were studied. The antioxidant enzymes like superoxide dismutase (SOD) and catalase were induced throughout the exposure span of 28 days. Percent induction was also increase with the days of exposure. Lipid peroxidation product, malondialdehyde was enhanced in the viscera tissue of chromium-exposed fish. Perturbation of locomotor behavior like decrease in distance travelled (m?min^?1) and in swimming speed (cm?s^?1) was observed in exposed fish. Chromium toxicity caused alterations in gill morphology like hypertrophy and hyperplasia in secondary lamellae followed by detached epithelium with severe necrosis. It can be concluded from the results that Cr intoxication in Gambusia fish, caused induction in antioxidant enzymes and lipid peroxidation, plus changes in gill morphology and locomotor behavior.