Hexavalent chromium induced oxidative, histopathological and hematological changes in snakehead fish, Channa punctatus

Aim: To evaluate the effect of hexavalent chromium on biochemical, hematological and histopathological responses and to assess its concentration in fish Channa punctatus. Methodology: Fishes were randomly distributed into Cr6+ treated groups, T1 (2 mg l-1), T2 (4 mg l-1), T3 (6 mg l-1), and one control (0 mg l-1) for 30 days exposure period. Potassium dichromate (K2Cr2O7) was used as source of Cr6+. The liver, kidney and blood were sampled after 10, 20 and 30 days intervals. Results: The significant (p < 0.05) increments in the concentration of hexavalent chromium and in the activities of enzymes (superoxide dismutase, catalase and glutathione reductase) as well as lipid peroxidation were recorded in the liver and kidney tissues of fish.However, the significant (p < 0.05) decline of reduced glutathione and total protein were noticed in both the tissues of fish. The red blood corpuscles count, hemoglobin and hematocrit significantly (p <0.05) decreased, while the white blood corpuscles count increased in blood of fish. Remarkably, the histopathological anomalies, pyknosis, hypertrophy and inflammation in liver and cavity reduction in renal tubules and glomerulus degenerative changes in kidney were prominently observed in fish. Conversely, the necrosis and vacuolization were observed in liver and kidney tissues of fish. Interpretation: The findings of the present study can be a useful tool as biomarkers for monitoring environmental pollution in aquatic ecosystem caused by hexavalent chromium. Key words: Biochemical, Biomarkers, Channa punctatus, Hematological, Hexavalent chromium, Histopathological