Effects of sublethal waterborne cadmium on gills in three teleosteans species: scanning electron microscope study

摘要

The effects of acute exposure for 96 h to a sublethal concentration of cadmium (300 μg L~(-1)) on the surface gill morphology of the teleosteans Cyprinus carpio, Australoheros facetum and Astyanax fasciatus were studied using Scanning Electron Microscopy (SEM). The main cadmium-induced gill damages in the three species were: structural alterations, oedema and fusion of adjacent secondary lamellae; there was a remarkable disruption of the gill epithelium in Australoheros facetum and excretion of large amount of mucus on the lamellae in Astyanax fasciatus. The reversibility of the alterations after a depuration period was also investigated; in all cases the fishes exhibited a considerable recovery of the gill structure after 96 h in a cadmium-free medium.