Effects of endosulfan sublethal concentrations on carp (Cyprinus carpio, Linnaeus, 1758): Morphometric, hystologic, ultrastructural analyses and cholinesterase activity evaluation

Endosulfan, an organochlorine pesticide, has been banned by most developed countries, although it is still produced, sold and used in developing countries. Used for control in crops, as well as for insect control in public health programs in some countries, its effects on the environment and its toxicity are still in discussion. For some researchers, its bioaccumulation in terrestrial organisms is considered irrelevant but for aquatic life it should be considered carefully. The present research work was to carry out an study on the effects of sublethal concentrations of endosulfan on the fresh water fish carp (Cyprinus carpio, Linnaeus, 1758). The fishes were exposed during 15 days to 0.001 mg/L of endosulfan using dimethylsulfoxide 0.1% (DMSO) as solvent. The acetylcholinesterase activity on the brain and axial muscle, as well as liver morphometric, histopathologic and ultrastructural analysis were studied. The hepatic somatic index and the livers weight showed smaller values when compared with the control groups, besides being also observed histopathological and ultrastructural alterations. It has not been observed significant alterations in the cholinesterase activity of both brain and striated muscle. These results suggest that the organochloride endosulfan caused toxic effects in the hepatic metabolism of the fish exposed to it in sub lethal doses.