Study of mortality rate, behavioral and histopathological changes in of roach, Rutilus rutilus caspicus exposed to Zinc sulfate

In this study aimed to determine behavioral and histopathological changes of Zinc in Roach (Rutilus rutilus caspicus) in acute toxicity tests for 96 h. The experiments were done by 200 Rutilus sp. fish with avrage weight 2.5±0.27g.To determinate behavioral and histopathological changes, 13 fish were distributed in groups of 0, 10, 30, 50, 70, 80 and 90 mg/l of Zinc. A group of fish was considered as control. Sulphate zinc salt was used as source of zinc. Thanks were aerated for 24 hours, so dissolved oxygen was maintained at range saturation by aeration. Test temperature, pH  value and dissolved oxygen were measured using portable multiparameter meter Hack (Model 2000).  Kidneys, livers, and gills were collected for evaluation. There was total mortality of 90 mg/l. Observations of behavioral response of  fish fingerlings expoused to zinc were such as vertical and downward swimming patterns, loss of equilibrium, convulsion, and spending more time at the bottom. Following this, the fish died with their mouth and operculum open. Gills presented vascular congestion, complete fusion of secondary lamellae, and epithelial cell hypertrophy. In the kidneys, changes such as Bowman’s capsule clearance, tubular degeneration, and glomerular capillary dilatation were common. Liver samples showed cytoplasmic vacuolization and cellular degeneration. Zinc induces a clinical condition of liver, gill and kidney damage in Roach. The results revealed, the use of Zinc in water can be harmful to increase fish mortality rate acute exposure to Zinc.