Evaluation of acute toxicity and histology effect on liver of glyphosate and atrazine in the African catfish Clarias gariepinus (Burchell 1822)

Aquatic organisms are exposed to chemical pesticides including glyphosate (Sharp 480 SL) and atrazine (Atraforce), two phytocidal molecules used for agriculture purposes in Benin. In this study, we assessed the acute toxicity of these two herbicides with emphasis on their histopathological effects on the liver of catfish Clarias gariepinus. One hundred and eighty juveniles of C. gariepinus (mean length 7.26 +/- 0.59 cm and mean weight 5.21 +/- 3.22 g) were exposed over 96 h to increasing concentrations of each phytocide. The values of 96 h-LC50 were 6.175 x 10(3) and 3.165 ppm, respectively for Sharp 480 SL and Atraforce. This indicates that Sharp 480 SL was nontoxic, while Atraforce displayed a moderate toxicity to C. gariepinus juveniles. During the tests, the behavioral responses (hyperexcitation, lethargy, loss of balance, discoloration of skin, etc.) that usually precede death were observed in exposed fishes, confirming the neurotoxicity of these phytocides. Histological alterations observed in liver of contaminated fishes were regressive changes, such as necrosis, hepatocyte vacuolation, nuclear degeneration, hepatocytes degeneration, sinusoids dilatation, etc. These results indicate that exposure to these herbicides had destructive effects on the liver of C. gariepinus.