EN
The studies were carried out on 30 hens of the Leghorn breed, which were being poisoned with DFP for 20 days at a rate of 0.05 mg per 1 kg. The activity of AChE was determined in the plasma, brain and spinal cord and the activity of NTE in the brain and spinal cord after 1, 5, 15 and 20 days. In poisoned hens the activity of AChE decreased after the 1st injection to 55 per cent and did not change for up to 20 days; it fell to 82 per cent in the brain after 5 days and was on the same level for up to 20 days. In contrast, the activity of AChE in the spinal cord decreased successively up to 71 per cent after 20 days. The NTE activity in the brain dropped to 46 per cent and in the spinal cord to 40 per cent after 20 days.