Studies of marginal zinc deprivation in rhesus monkeys. V. Fetal and infant skeletal effects.

Skeletal maturation was evaluated in newborn and infant rhesus monkeys that had been subjected to a marginally zinc-deficient diet (4 ppm zinc) from conception through 12 months of postnatal life. Serial radiographic assessment of skeletal development was performed and compared to both ad libitum and pair-fed controls. Radiographs were obtained at birth and at 1, 3, 9, and 12 months of age. In each age group a maturation indicator was selected to identify individuals with abnormal skeletal maturation defined on the basis of presence of epiphyseal ossification centers. Animals were compared only within a given sex group. Additionally, to evaluate endochondral bone mineralization, the appearance of the zone of provisional calcification on the metaphyseal side of the growth plate and the width of the growth plate were assessed. A marginal level of zinc deprivation during gestation and during the 1st yr of life was found to be associated with significantly delayed skeletal maturation and defective mineralization. This abnormality of bone mineralization has many features similar to human rachitic syndromes and suggests that zinc plays an important role in endochondral bone formation.