The use of chemical pesticides and herbicides has increased environmental pollution and affected ichthyofauna in the watersheds where they are used. We studied the effect of an herbicide, triazine, on the kidneys of two species (Caquetaia kraussii and Colossoma macropomum) widely found in Caribbean and South American rivers. In Venezuela, these species are abundant and have a high aquaculture potential because they may be cultured and reproduced in captivity. Four kidney samples from juveniles of each species exposed to the herbicide were examined by Transmission Electron Microscopy. Kidney tubule alterations included loss of plasmalemma and cell interdigitations, misshaped mitochondria, decrease in rough endoplasmic reticulum and free polysomes, and the presence of autophagic vacuoles and primary lysosomes. These alterations at the cellular level may explain fish behaviour in terms of kidney tubule pathology, and relative amounts and conditions of organelles within affected cells.
Keywords: Caquetaia kraussii, Colossoma macropomum, kidney, herbicide, ultrastructure, pathology, stress markers