Histopathology of common silver barb Puntius gonionotus liver at Klong 7 agricultural area, Pathum Thani Province

Abstract

At present, there is growing awareness for the increasing use of synthetic insecticides in agricultural area. Organophosphate insecticides, which are mainly used in agricultural areas, often contaminate into the freshwater ecosystem by the run-off from the land and then to aquatic system. There was less information on the toxicity of affected toxicants on fish in the environment. Therefore, the objectives of this study were to assess the histopathology of Puntius gonionotus liver, to determine the organophosphate insecticide residues in water at Klong 7 agricultural area, Pathum Thani Province and to study the toxicity of endosulfan on the liver of 4 month old Puntius gonionotus at the concentration levels of 0.06, 0.25, 0.50 and 1 ppb. The fish samples and water samples were collected from three sites along 20 kilometers of Klong 7 sub-canal from March to December 2004. The liver of fish from Klong 7 group, control group and endosulfan treated groupwere prepared for histological study by paraffin technique and staining with H&E. The tissue sections for histochemical study were prepared by frozen technique and staining with Oil red O and PAS technique before observed under the light microscope. The results showed that the percent relative liver weight (%RL) of fish liver from Klong 7 and endosulfan treated liver at the concentration of 0.06, 0.25, 0.50 and 1 ppb were significantly lower than the control group (p [is less than or equal to] 0.05). The results of histopathological study of Klong 7 fish liver and endosulfan treated fish liver exhibited various lesion of changes from mild to severe, i.e. hydropic swelling, hyalin granule accumulation, foci and diffuse necrosis near the blood vessel, blood congestion in sinusoid and central vein, subcellular space inflammation, and endothelial of blood vessel ruptured and thickening. Lymphocyte and granulocyte infiltrations were seen in the inflammatory area. In the histochemical studies, the glycogen accumulation decreased in Klong 7 fish liver, but increased in endosulfan treated liver. The lipid accumulation of Klong 7 fish was found, but in endosulfan treated group, decreasing of lipid accumulation in cytoplasm of hepatocytes was seen. The severe damage of endosulfan treated liver depends on the concentration. The quantitative studies of organophosphate insecticide residues in water of Klong 7 by GC/FPD showed non-detectable result