Relationship of Maternal Dietary Zinc during Gestation and Lactation to Development and Zinc, Iron and Copper Content of the Postnatal Rat

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Abstract
High levels (0.2 and 0.5%) of zinc were fed to adult female rats beginning at zero-day age of the fetus and continued to day 14 of lactation to study the development and iron, copper, and zinc status of zero- and 14-day-old postnatal rats. The results were compared with rats fed a basal diet containing 9 ppm zinc. Growth reduction, in terms of dry matter content, was characteristic of the zero- and 14-day-old young from mothers fed 0.5% zinc. Though no anatomical malformations were observed, the incidence of stillbirths was high in the 0.5% zinc group. Young from mothers fed 0.2% zinc were larger in body size than those from mothers fed the basal diet. Total zinc and concentration of zinc were elevated in zero- and 14-day-old young by both high zinc diets. Young from mothers fed 0.5% zinc contained higher levels of zinc than those from mothers fed 0.2% zinc. Bodies of newborn young from mothers fed 0.5% zinc contained significantly less total iron and concentration of iron, whereas the liver contained significantly more iron. At 14 days of age the whole animal and body of young from mothers fed 0.5% zinc contained significantly less total iron and concentration of iron. Liver iron in these young was lower than found in the liver of newborn, and total iron and concentration of iron in the liver were similar for all groups. Total copper and concentration of copper in the whole animal and body of the newborn rats were not altered due to treatment. Total copper and concentration of copper in the liver were significantly lower only in the newborn from mothers fed 0.5% zinc. After 14 days, total copper and concentration of copper were significantly lower in the whole animal, liver and body of young from mothers fed either zinc diet than in young from mothers fed the basal diet. In general, a larger reduction in copper occurred in the young from the 0.5% zinc treatment. Mothers fed 0.2% zinc gained more weight during gestation. Dietary treatments had no effect on body weights during lactation. Livers of maternal animals fed excess zinc contained elevated zinc, and reductions in both iron and copper.