Effect of Atrazine, Glyphosate and Quinclorac on Biochemical Parameters, Lipid Peroxidation and Survival in Bullfrog Tadpoles (Lithobates catesbeianus)

Increased use of pesticides worldwide has led to damage not only to natural ecosystems but also to nontarget species. This study assessed the effects of different concentrations of the herbicides atrazine, glyphosate, and quinclorac on biochemical parameters, lipid peroxidation, and survival in tadpoles of Lithobates catesbeianus (bullfrog). Two hundred eighty-eight tadpoles were acquired from a frog farm in the south of Brazil. All animals were kept in aquariums under controlled laboratory conditions for 7 days and exposed to commercial formulations of atrazine (5, 10, and 20 mu g/L), glyphosate (36, 72, and 144 mu g/L), and quinclorac (0.05, 0.10, and 0.20 mu g/L) for 7 days thereafter. The concentrations used in this study are similar to the levels of these herbicides found in natural water bodies. After exposure, gill, liver, and muscle samples were removed from each animal for quantitation of glycogen, total lipids, triglycerides, cholesterol, total proteins, and lipid peroxidation. Atrazine, glyphosate, and quinclorac exposure induced a significant decrease in levels of glycogen and total lipids in gill, liver, and muscle. Triglycerides levels in the gill increased after exposure to glyphosate, and decreased after exposure to atrazine and quinclorac; their levels in liver and muscle decreased on exposure to all herbicides. Cholesterol and total protein levels decreased in liver and muscle for all three herbicides. All tissues exhibited increased lipid peroxidation after exposure to all herbicides. In conclusion, exposure to the herbicides tested in this study induced significant changes in biochemical parameters and increased lipid peroxidation levels in tadpoles of L. catesbeianus.