Histopathological lesions in liver and gill of Capoeta capoeta gracilis in exposed to butachlor

Abstract Different organisms like aquatics are constantly exposed to pesticide residues, this study's overall assessment patho-biological changes in gills and livers of Capoeta capoeta gracilis during exposure to butachlor pollutant. First of all the 96-hour lethal concentration of the toxin was calculated as 46.2 mg per liter. Then, 96 fish were divided into four groups: one control group and three experimental groups (with concentrations of 0.2, 0.4, and 0.8 mg l-1) and were exposed for 2 weeks. In the end point, histological changes were studied by hematoxylin and eosin staining method in light microscopy. Lethal concentration of this toxin was 2.46 mg/l that means moderate toxicity of this species. There was many histological changes in the gills of fish treated with butachlor include: hyperplasia, shortening the secondary lamella, edema, fusion, hemorrhage and atrophy in compared to the control group. Treatment with liver butachlor cause obstruction, dark granules, necrosis, and bile stagnation and sinusoid dilution in studied fish. The results of this study showed that in both studied organs with increase of toxin concentration, more severe tissue damage was observed, so gill and liver tissues of this fish could be used as an appropriate biomarker for pollutant measurement.