EFFECT OF THE SEVERITY OF MATERNAL ZINC-DEFICIENCY ON PREGNANCY OUTCOME AND INFANT ZINC STATUS IN RHESUS-MONKEYS

To investigate the effects of the severity of maternal zinc deficiency on early development, rhesus monkeys were fed diets that were either moderately zinc-deficient (MZD) (2 mug Zn/g) or marginal in zinc (M) (4 mug Zn/g throughout pregnancy and lactation. Dams in the MZD group developed overt signs of zinc deficiency. Compared with control dams fed diets adequate in zinc (C) (50 or 100 mug Zn/g), both M and MZD dams showed low mitogen response. Pregnancy outcome was similar in all groups, and infants were considered healthy at delivery. From birth until d 30, infants were closely monitored for signs of zinc deficiency. On d 30, infants were killed and tissues were analyzed for several parameters reported to be affected by zinc status. MZD infants tended to have lower plasma zinc concentrations than C infants, although the difference was only significant at d 14. M infants tended to have lower plasma zinc concentrations than C infants. Mitogen response was lower in MZD and M infants than in C infants. However, mitogen responses were similar in MZD and M infants. Liver zinc concentrations were similar among the three groups of infants; however, zinc and metallothionein concentrations in (10 000 x g) liver supernatant fractions were lower in the MZD and M groups than in the C group. Zn-65 absorption/retention was higher in MZD and M mothers and infants than in C mothers and infants; there were no marked differences between MZD and M mothers or infants. In contrast to whole-body absorption, Zn-64 uptake/retention by isolated hepatocytes was similar among the three infant groups. Plasma metallothionein concentrations were higher in the MZD mothers during the 1st, 2nd, and 3rd trimester than in the M or C mothers and higher than C mothers on d 30 postpartum; plasma metallothionein concentrations were similar among the three groups of infants. These results demonstrate that feeding a diet containing 2 mug Zn/g to rhesus monkeys during pregnancy and lactation results in marked signs of zinc deficiency, whereas feeding a diet containing 4 mug Zn/g results in only subtle signs.