EFFECT OF THALIDOMIDE ON EMBRYONIC AND POST-EMBRYONIC DEVELOPMENT OF THE CHICK

Abstract

Breeding hens were fed diets containing 0, 1.32 or 2.64 g thalidomide (TLD) per kg of feed. There were no malformations in any of the 330 chicks and none in the unhatched embryos when the dam diet contained an adequate level of niacin, but day-old body weights of chicks from TLD-fed dams were consistently lower in comparison with chicks from untreated dams. This growth-depressing effect persisted to 8 weeks of age when such chicks were fed a complete diet. The addition of excess niacin (77 mg/kg) to the diet of the chicks from TLD-fed mothers resulted in return to normal growth of these birds by 5 weeks of age. The absence of TLD in the blood plasma of the chicks at 5 weeks of age indicates that the depressing effect does not appear to be due to the participation of this drug in metabolic processes determining growth of these chicks. Furthermore, it appears that niacin is able to correct the abnormality caused by TLD in embryonic development.When TLD was fed to breeding hens, at the rate of 1.32 g per kg of a diet deficient in niacin, some malformations appeared in embryos developing from their eggs. No malformations resulted from a deficiency of niacin alone, or from the presence of TLD alone in diets of breeding females.