Abnormalities in the offspring of hens subjected to chronic effect of 131I

Modern radiobiology and medicine is faced with distant consequences of 131I chronic effects on descendants of animals and people suffered from the Chernobyl’ accident. Different disturbances in embryogenesis and congenital malformations are observed in the offspring of those whose thyroid gland was exposed to irradiation with 131I. Nevertheless, a long term prediction of 131I chronic effect in multiple generations is not still cleared up. So, we studied abnormalities of development in seven generations of offsprings which were obtained from Russian white hens subjected to chronic influence of 131I during 30 day administration of the isotope at equal daily doses of 0.11, 1.1, 2.1 and 4.6 mBq/kg. A total of 2573 offspring chickens were obtained 3, 6 and 12 month after the isotope administration has been started, and then they were surveyed for 1.5 to 2.5 years and compared to 2782 control chickens of the same age whose parents were not subjected to irradiation. The offspring of 131I radiation-exposed poultry was characterized by higher postnatal death rates, accelerated sexual maturation which was expressed in an earlier molding and 1 st egg laying time, as well as with some decrease in body weight of mature birds for the majority of the generations. The offspring of the first three poultry generations from the group exposed to 131I at a dose of 1.1 mBq/kg had tumors on the jaws, neck and/or conjunctiva. Among the chicken generations 4 and 5, the degenerates appeared at a frequency of 0.75 % with abnormalities mostly manifested as head defects (e.g., absence or deformation of eyes or X-shaped jaw decussations). The first four offspring generations older than 6 months being under test exhibited tumors similar to lymphoreticulosarcoma in soft tissues at a frequency from 0.8 to 4.7 %. Chickens death in the experimental groups resulted mainly from disorders of gastrointestinal tract, liver, heart and kidney. An increased mortality seemed to be related with changes occurred in the course of embryogenesis leading to improper regulation and adaptation in early postnatal period.