Teratological evaluation of formulated Dicofol and Deltamethrin in chick embryo

Abstract

In the present work, teratogenic potential of commercial formulations of two insecticides: dicofol (Colonel-S) and deltamethrin (Decis) were evaluated in developing chick embryo by observing certain changes in structural, biochemical and pathological parameters. The study consisted of three experimental plans which were based on exposure of fertilized eggs of Gallus domesticus to each insecticide on three critical periods of their embryogenesis. These eggs were immersed in aqueous emulsions (prepared in distilled water) of each insecticide at 250, 500 and1000 mg L¬-1 of dicofol and 12.5, 25 and 50 mg L¬-1 of deltamethrin which were based on recommended dose (500 mg L-1 of dicofol and 25 mg L-1 of deltamethrin) of each insecticide used for crop protection technique. In first experimental plan, the subjects were exposed with these chemicals on 0 day of incubation and their teratological evaluation was carried out on Embryonic Day (ED) 4, 7 and 10. In second experimental plan, eggs were treated on ED 4 followed by their sampling on ED 7, 10 and 16. Fertilized eggs were exposed on ED 7 in the experimental plan 3, and embryos were sacrificed on ED 16. All recovered embryos on ED 4, 7 and 10 were evaluated for survivability rate, wet body weight, gross morphological malformations and biochemical estimations of whole body, while those sacrificed on ED 16 were examined for above mentioned external teratological parameters, then histopathological (liver) and biochemical studies (brain and liver), and skeleton preparations were done in these treated animals. The result revealed that administration of dicofol and deltamethrin in developing chick embryo caused significant decrease in their survivability success, wet body weight and increase of various external (such as general growth retardation, hematomas, subcutaneous hemorrhage, ectopic viscera, anophthalmia, microphthalmia, microcephaly, anencephaly and exencephaly) and skeletal malformations (poor ossification of axial and appendicular skeleton bones, scoliosis an