Toxicity of aldicarb in young chicks.

Enzyme and locomotion changes due to carbamate treatment were investigated during and following oral administration of aldicarb (0.2 mg/kg body weight/day x 7) to six-day-old chicks. Brain acetylcholinesterase (AChE) and neurotoxic esterase (NTE) were measured at three times during the one week of treatment, and again on days 1, 3, 6, 10, 20, 30 and 40 after the last dose. Gait analysis was evaluated on each posttreatment day at which the biochemical assays were performed. Multiple doses of aldicarb resulted in a significant reduction in the weight of the treated chicks beginning 6 days after the last treatment. Treatment with aldicarb had no significant effect on brain NTE during or after dosing. The AChE levels in treated chicks were significantly lower than those of controls only 24 hr after the first dose. Significant alterations in the locomotion of the chicks was seen from day 1 until day 40 after last treatment. Treated chicks had significantly shorter stride length, longer stride width and wider sine of the angle of placement than the controls. This study demonstrated that repeated exposure to aldicarb altered locomotion of the chicks for several weeks after cessation of exposure with no significant esterases inhibition, indicating that behavioral alterations due to pesticide exposure need not be associated with enzyme changes.