Antagonistic effect of zinc in lead treated developing chick embryos.

Lead (50 micrograms) and zinc (100 & 200 micrograms) alone and in combination, were injected on 7th day of incubation into the yolk sac of developing chick embryos. The deformities induced by Pb alone included reduced hatchability, growth retardation, hydrocephalus, defective beak and legs, microphthalmia, anophthalmia and curling of hair. The concurrent exposure with Zn (200 micrograms), however, provided a remarkable protection against lead induced deformities, reflected in terms of almost normal development of chick embryos with increased hatchability and lower incidences of malformations, and mortality.