Zinc Induced Histopathological Alternations in Gill, Liver, and Kidney of Freshwater Fish Gonoproktopterus kolus (Sykes)

The present study aims to investigate the histopathological changes in gill, liver, and kidney of fresh water fish Gonoproktopterus kolus (Sykes). The fingerlings of fish were exposed to Zinc (Zinc sulphate) in acute toxicity experiment (96 hrs.). The LC0 and LC50 concentrations were 2.430 ppm and 4.860 ppm respectively. After acute exposure, fish were sacrificed and tissues were obtained separately from control and LC0 and LC50 groups. These tissues were fixed in Bouin's fluid and standard protocol was followed to study histopathological alterations in gill, liver and kidney of experimental fish. In gills, fusion and degenerative changes were observed in secondary gill lamellae. In liver, hepatocytes showed hypertrophy due to degenerative changes in cellular structure. Empty hepatocytes showed shifting of nucleus. Kidney showed degenerative nuclei in the epithelial lining of the tubule. Haemopoetic tissue showed hypertrophy and disarray. Distended glomerulus was observed. Renal tubules showed disarrangement as compared to control. Thus, in present investigation, it was observed that heavy metal zinc is affecting the fishes at tissue level, which may interfere in physiological processes.