Effect of the dietary manganese level on tissue manganese, iron, copper and zinc concentrations in female rats and their fetuses.

In order to study the effect of dietary manganese on the content of manganese, iron, copper and zinc in maternal and fetal tissues, six diets with different levels of manganese (4, 24, 54, 154, 504 and 1004 mg Mn/kg dry diet) were fed to Sprague-Dawley female rats from the time of weaning. The animals were mated and the offspring collected by cesarean section at day 21 of pregnancy. Non-pregnant female rats served as respective reference groups. Concentrations of copper as well as manganese were higher in the livers of pregnant rats with the highest manganese intake, whereas in non-pregnant animals the dietary manganese level had no appreciable effect on manganese or copper concentrations in the liver. On the other hand, the iron content of the livers of both pregnant and non-pregnant female rats fell as the manganese level of the diet increased. The hemoglobin values of dams on the highest levels of dietary manganese were also slightly reduced. The manganese content was highest in the offspring of dams given the largest amounts of manganese. The manganese level in the maternal diet had the opposite effect on the fetal iron concentration, and the zinc content of fetuses of dams on the highest dietary manganese level was slightly elevated. No gross malformations or bone structure anomalies could be observed in the fetuses, and the manganese intake of the dams was not found to have influenced essentially the fetal weights and the dry matter and ash contents.