Effects of iodized salt on the histopathology of the gills and liver in Rhamdia quelen and Metynnis maculatus

Abstract

Table salt has been used as a reference substance in toxicological studies on fish and as an antiparasitic agent in aquaculture. The objectives of this work were to evaluate the sensitivity of Rhamdia quelen and Metynnis maculatus to iodized salt and to assess the possible changes in the gills and liver resulting from subchronic exposure of fish to this compound. The iodized salt toxicity levels after 96 h of exposure were 11.4 and 10.8 g L−1 for R. quelen and M. maculatus. None of the observed changes in the livers of the studied fish could be unequivocally correlated with salt exposure. In turn, it could not be entirely ruled out that the changes found in the gills, including epithelial lifting, oedema formation and vascular congestion, were caused by exposure of fish to salt.