Studies of marginal zinc deprivation in rhesus monkeys. IV. Growth of infants in the first year.

Growth was evaluated in rhesus monkey infants that were the offspring of females given a marginally zinc-deficient diet (4 micrograms/g zinc) from the beginning of pregnancy and through 12 months of postnatal life. These zinc-deficient (ZD) infants were compared to controls whose mothers were fed a complete diet, either ad libitum or pair-fed to zinc-deficient dams, throughout gestation and lactation. Male ZD infants had evidence of growth retardation at birth. In contrast, growth retardation in female ZD infants was not observed until 1 month of age. From 3 to 9 months of age (late lactation and subsequent to weaning) ZD infants attained weights similar to those of the control group. However, analysis of crown-rump and femur length indicated that ZD infants' growth was less than optimal throughout the entire 1st yr of observation. In addition, skinfold thickness was markedly higher in ZD than in control infants in the postweaning period. In the juvenile period (9-12 months of age) both male and female ZD animals fell behind controls in body weight. ZD juveniles were also hypogeusic, as determined by a quinine acceptance test. Low weight ZD infants had reduced somatic growth as reflected in sitting height, long bone growth, head circumference, and limb circumference. Regression analysis indicated that impaired growth rates from 9 to 12 months were associated with both lower food intake and reduced food use efficiency. Plasma zinc concentration was, in general, inversely related to weight gain in both groups during the 1st yr.