RÉSUMÉ
A model of BALB/c mice was developed to determine the effects of zinc supplements on immune responses during certain stages of ontogeny. The mice received zinc acetate in drinking water concentrations of 500 and 1000 mg/l during the periods of gestation, lactation and postweaning. The sequence employed in this study was: (I) 0/0 (II) 500/500 (III) 1000/1000 (IV) 0/0/0 (V) 500/500/500 and (VI) 1000/1000/1000 with their respective controls. No changes were observed in the general appearance, growth curves, hematocrit or signs of achromotrichia between treated and control animals. Group II and III showed a significant increase in 3H-thymideine-determined splenic lymphoproliferation, while groups V and VI exhibited and important decrease. A significant increase in plaque-forming cell response (IgM) was observed after the period of lactation in groups II and III as well as i groups V and VI. Zinc concentrations determined by atomic absorption in liver and thymus were significantly higher in all treated mice 42 days after bith. Results suggest that for carefully monitored periods and doses, oral zinc supplements might have a beneficial effect over some immune responses in the perinatal stages