The Micro Nucleus, Haematology and Toxicity effects of Glyphosate-based Herbicide 'Glysate' on post juveniles of African Catfish (Clarias Gariepinus) Burchell 1822

Glyphosate (N-phosphonomethyl glycine) is a broad spectrum systemic herbicide used extensively in weed control. The present study was designed to evaluate the toxicity effect of glyphosate on 300 post juveniles (50g±0.96g; 22cm±0.02) of Clarias gariepinus (Burchell, 1822) after exposure to acute concentration levels of 31, 33, 35, 37 and 39 mg glyphosate/L of clean water. The experiment was completely randomized as each treatment were all replicated thrice. Glyphosate toxicity (96 hr LC50) to Clarias gariepinus was determined at 35 mgL-1 after exposure by probit analysis. Based on the LC50 value, three sublethal test concentrations of 3.5, 7, 17.5mgL-1 corresponding to 1/10 LC50=3.5mgl-1, 1/5 LC50=7mgl-1, ½ LC50=17.5mgl-1 were selected for sub lethal experiment. A set of fish were also maintained simultaneously in water as a control experiment during the exposure periods. Blood samples were taken at intervals of day 1, 4 and 8 for assessment of hematology and micronucleus frequency. The results showed that glyphosate is toxic to Clarias gariepinus and fish generally though dose dependent as it significantly (p