Abstract

The effect of dichlorvos on reproductive performance of laying hens was studied. Seven weeks old pullets with an average weight of 557.5 ± 9.5 g were divided into four groups and fed ad libitum with commercial poultry feeds contaminated with 0.01, 0.02 and 0.04% dichlorvos (w/v). The group without dichlorvos served as the control. Exposure to dichlorvos was continued until nine weeks after the hens started laying eggs. There was a significant reduction (p<0.05) in feed intake between the control group and those exposed to dichlorvos.  Egg laying was delayed in the hens exposed to the pesticide by as much as eighteen weeks. The ages of the hens at first egg  lay were 18 weeks for the control, 23 weeks for hens fed on 0.01 and 0.02% contaminated diet and 36 weeks for those fed on 0.04% contaminated diet. The average daily egg production was reduced from 5 eggs in the control group to 1 egg in 0.04% contaminated group. The protein contents of the egg (yolk and egg-white) and cholesterol level of the egg yolk were lowered in birds exposed to dichlorvos. There was no significant difference in the weight of eggs between the control and those exposed to pesticide. Results of this study suggest that exposure of laying hens to dichlorvos could affect their reproductive success.

Key words: Dichlorvos, reproductive success, sexual maturity, egg laying hens.