Acute Toxicity of Zinc to Rainbow Trout Salmo gairdneri

Abstract

Heavy metals such as zinc, copper, lead, cobalt and nickel hemolyzed erythrocytes of several kinds of animals. The hemolytic a ctivity of each heavy metal was species-specific to test animals and zine affected the erythrocytes of rainbow trout most profoundly. Microscopic observation showed that a part of the epithelium of the gills of rainbow trout was torn off in the later stage of zinc poisoning. In addition, heavy metals took away the elasticity from salmon eggs which we used as a model of cell membranes of the erythrocytes and the epithelial cells. There was a close relationship in the order of the efficacy of heavy metals between the degree of hemolysis and the loss in elasticity. Not only the hemolysis of erythrocytes but also the damage of the gills were probably due to the loss in elasticity of the cell membrane. Thus we concluded that zinc had a kind of cytotoxicity especially to rainbow trout.