RUBRATOXIN-B AND CHICK EMBRYOGENESIS - EXPERIMENTAL-STUDY

The effects of rubratoxin B were studied on the chick embryos of 1-3 days of incubation (groups A, B and C). Rubratoxin B was dissolved in propylene glycol and injected into the air sacs of the eggs at doses ranging from 0.0005-0.007 mg/egg. The controls received an equal amount of propylene glycol only (0.1 ml/egg). All the embryos including controls were examined at day 7. In all, 720 eggs were utilized for this investigation. The percentage survival of the embryos on incubation day 7 ranged from 67-40 in group A, 77-43 in group B and 93-60 in group C. The LD50 for the embryos treated on days 1 and 2 was 0.001 and 0.005 mg/embryo, respectively. Gross malformations such as short and twisted limbs, short and twisted neck, exencephaly, microphthalmia, everted viscera, reduced body size and hemorrhage over the body were observed. The frequency and the types of gross abnormalities did not vary much in all the groups. The incidence of malformations in the controls was low. Microscopic examination of day 1 treated embryos (group A) showed the various types of cardiac anomalies including aortic stenosis, ventricular septal defect, thin ventricular wall, atrial septal defects and malformations of the valves. The incidence of these cardiac anomalies was low in the experimental embryos. No cardiac anomalies were observed in the control embryos. Rubratoxin B is teratogenic to the overall development of the chick embryos including the heart.