Enzyme and behavioral changes in young chicks as a result of carbaryl treatment

Certain biochemical and behavioral effects of carbaryl were investigated in chicks. Six-day-old birds received 100 mg/kg body weight (bw) per day carbaryl for 7 d. Brain acetylcholinesterase (AChE) and neuropathy target esterase (NTE) were measured at 24 h after the first, third, and fifth dose during the 1 wk of treatment, and then at d 1, 3, 6, 10, 20, 30, and 40 after the last dose. Gait analysis was evaluated on each posttreatment day. No significant reduction in both NTE and AChE activities was noticed throughout the experiment. However, carbaryl altered the locomotion of the chicks from d 1 until d 40 after last treatment. The stride length of the treated birds was significantly shorter than that of the controls. A significant increase in the stride width and sine of the angle of placement was noticeable throughout the period of the experiment. Thus, treated chicks walked with abnormal gait. Delayed ataxia and paralysis occurred 20 d after the last treatment and lasted until the end of the experiment or eventually death.