Biochemical and histopathological effects of glyphosate herbicide on Nile tilapia (Oreochromis niloticus).

In Oreochromis niloticus that had been exposed for 3 months to sublethal concentrations (5 and 15 ppm) of the commercial glyphosate herbicide (C(3)H(8)NO(5)P) Roundup, the organs exhibited varying degrees of histopathological change. In the gills filament cell proliferation, lamellar cell hyperplasia, lamellar fusion, epithelial lifting, and aneurysm were observed. In the liver there were vacuolation of hepatocytes and nuclear pyknosis. Kidney lesions consisted of dilation of Bowman's space and accumulation of hyaline droplets in the tubular epithelial cells. The structural damages could be correlated to the significant increase (p </= 0.05) in aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase activities in the second and third months of exposure. The results indicated that long-term exposure to glyphosate at sublethal concentrations had adverse effects on the histopathological and biochemical alterations of the fish. Copyright 2003 Wiley Periodicals, Inc. Environ Toxicol 18: 260-267, 2003.