Brain cholinesterase activity of bobwhite acutely exposed to chlorpyrifos

Abstract

Abstract Northern bobwhite, Colinus virginianus, were orally dosed with the organophosphorus insecticide chlorpyrifos to examine effects on brain chohnesterase (ChE) activity. Two-week-old quail were acutely exposed and euthanized at selected times following gavage-dosing, ranging from I to 120 h later. The ChE activity was determined in treated birds and compared to concurrently tested control (corn oil) birds. It was found that a lag time of 2 to 4 h following exposure was necessary to detect significant ChE depression caused by chlorpyrifos. The lowest dose that produced ChE depression in these tests was between —30 and 50 mg chlorpyrifos/kg body weight, with some mortality occurring at the high end of that range. Depression typically persisted for at least 24 h.