Effects of trichlorfon organophosphate on the morphology of the gills and liver of Pseudoplatystoma corruscans.

Possible changes in the morphology of the gills and liver of P. corruscans after exposure to TCF were evaluated. The fish were distributed into five groups in triplicate (n = 10 in each group: 0.0; 0.125; 0.25; 0.5; 1.0 mg/L of the commercial product NEGUVON®, for 96 h. TCF induced a high histopathological index associated with circulatory disorders (congestion and aneurysm), as well as progressive changes (lamellar hyperplasia, capillary dilation, epithelial detachment and edema) at the highest concentrations (0.25; 0.5 and 1.0 mg/L). In addition to the histopathological disturbances, there was an increase in the levels of neutral glycoproteins and alterations in the histomorphometry of the secondary lamellae (total height, apical region, median, basal and interlamellar) at the highest concentrations. In the liver, the alterations were more intensified, in addition to circulatory (congestion) and regressive disturbances (loss of hepatocyte architecture and accumulation of intracellular substances), progressive alterations (focal necrosis) were observed, indicating a high degree of hepatic tissue involvement. The results indicate that the use of TCF concentrations above 0.25 mg/L promotes histopathological, histomorphometric and histochemical changes in the gills and liver of P. corruscans, imposing a biological risk that affects the aquatic environment and the health of fish.