No abstract

SummaryStructural changes taking place in the chorioallantoic membrane (CAM) of embryonated hen's eggs during incubation were followed up by histological, histochemical and electron microscopic methods. The allantoic sac surrounds the amnionic sac and also the yolk sac by the 7th to 11th day, respectively, and forms together with the chorion the CAM. The mesenchymal layer placing between the chorion of ectodermal and the allantoic layer of entodermal origin develops from the somatic and splanchnic‐pleure of the parietal mesoderm.The CAM is composed of three different layers, i.e. chorionic epithelium, mesenchyme and allantoic epithelium. The chorion comprises 2 layers of cubical epithelial cells. In between the 2 layers capillaries and directly under the shell membrane vascular sinuses can be found. Blood circulating in the sinuses is separated from the air in the pores of the shell membrane by the adacent epithelial cell‐projections of 0,2 μm thickness, the basal membrane (0.1 μm) and the sinus endothelial layer of 0.2 μm thickness. The mesenchymal cells are of star‐like form. The allantioc epithelium is built of one layer of fusiform cells with oval‐shaped or rod‐like nuclei.

Development of the liver in goose embryo was studied ultrastructurally. The structural changes of the liver in the 14, 21, 24 and 28 days old embryos were investigated. The liver primordium of endodermal origin localized around the ductus venosus. The hepatocyte trabeculae proliferating into the ductus venosus, first divide the lumen into wide sinusoids then with the number of trabeculae increasing the sinusoids become narrow on the 15th day. The hepatocytes in 11–14 days old embryos are less differentiated and poor in cell organelles. There are many fat drops in multi vacuolic form at the hepatocytes in 21 days old but specially in 27 days old embryos. The liver contain little connective tissue, it is formed between days 17 and 21. The endothelial cells comprise well developed endoplasmic reticulum. The Kupffer‐cells contain lipid drops after the 22th day.

Teratogenic effects of methylparathion / Wofatox 50 EC/ and Parathion 20 WP as positive control material were tested in pheasant embryos. On the 12th day of incubation 0.1 ml of the emulsions or suspensions of the insecticides at different concentrations was inoculated into the air space of embryonated eggs. The following dose levels were employed: 27 and 270 mg/kg egg of Wofatox 50 EC, and 10 mg/kg of Parathion 20 WP. Morphological changes were evaluated by macroscopic, skeletal staining and light microscopic examinations of the embryos. Primary hypoplasia or atrophy developed in the cervical musculature /m. longus colli/ accompanied by lordosis and scoliosis of the cervical spine. In most cases we also found cyllosis .

The insecticide formulation BI 58 EC was tested for teratogenicity in chicken embryos, with particular reference to degradation of the active ingredient (dimethoate) after the treatment of embryonated eggs. The pesticide was diluted in water to a concentration level of 0.8%, and the emulsion was injected into the air space in a volume of 0.1 ml/egg, or hen's eggs were treated by the immersion technique. Residues of dimethoate were measured in the samples on days, 13, 15 and 19 of the incubation of chicken embryos, and morphological examinations were performed simultaneously. Analytical chemistry data indicated a slower degradation of dimethoate in embryos after the immersion of eggs, and cyllosis was remarkable in this group among the sporadic developmental anomalies. The liver tissues of both treated groups exhibited severe fatty infiltration.