sublethal effect of nanosilver on the structure of gill of caspian roach (rutilus rutilus caspicus) fingerlings

widespread use of nanosilver can be led the contamination of aquatic environment and impact on living organisms such as fishes. we investigated histopathological changes in the gills tissue of caspian roach fingerlings after two weeks exposure to sublethal concentrations of nanosilver. following one and two weeks exposure, necrosis, shortening of secondary lamellae, edema, destruction of epithelial lamella, shortening of secondary lamellae, epithelial lifting and curling of secondary lamellae were observed in gill tissues. this observation showed that exposure to sub-lethal concentrations of nanosilver is caused damages in the gill tissues of caspian roach. the results demonstrated direct correlation of gill tissue damage and toxin exposure i.e. increasing nanosilver concentration is caused more tissue damage. hence, histopathological changes of gill can considered as a proper indicator for nanosilver contamination of aquatic environments.