Abstract
The toxicological effects of three commonly used pesticides in Iran on the fries of Caspian kutum (Rutilus kutum, Kamensky, 1901) were investigated through determining 50.00% lethal concentration (LC(50)) 96hr and cholinesterase (ChE) inhibition. The LC(50) 96-hr of carbaryl, glyphosate, and malathion were equal to 11.69, 6.64, and 0.97 mg L(-1), respectively, that were considered as harmful (10.00 - 100 mg L(-1)), toxic (1.00 - 10.00 mg L(-1)) and very toxic (< 1.00 mg L(-1)) compounds for this species. The exposure of fries to sub-lethal concentrations of the pesticides over 15 days indicated that the average of ChE activity in the head and trunk were 1086.89 ± 124.34 and 627.36 ± 99.60 mU min(-1) per mg protein, respectively, with a significant difference relative to each other. There was a significant difference between fry exposed to all three pesticides and the control group in cholinesterase inhibition. The fries exposed to carbaryl (890.12 ± 28.08 mU min(-1) per mg protein) and glyphosate (891.77 ± 31.61 mU min(-1) per mg protein) showed lower ChE inhibition than those exposed to malathion (790.00 ± 58.14 mU min(-1) per mg protein).