Effects of chemical species of selenium on maternal transfer during pregnancy and lactation

AimsThis study compares the transfer from mother to fetuses and pups of selenium (Se) in the form of selenite, selenate, and selenomethionine (SeMet) labeled with different homo-elemental isotopes.Main methodsTo completely substitute endogenous Se with natural abundance with Se enriched with a single stable isotope (82Se), female Wistar rats delivered by mother fed 82Se-selenite were fed Se-deficient diet and drinking water containing 82Se-selenite immediately after weaning, and then mated with male Wistar rat at the age of 15–17 weeks. The pregnant rats were divided into two groups. One group was fed Se-deficient diet and drinking water containing 76Se-selenite, 78Se-selenate, and 77Se-SeMet from gestation days 11 to 20. The other group was fed the same diet and drinking water containing the three Se species after delivery for 10 days of lactation. Non-pregnant rats were also fed Se mixture and Se-deficient diet for 10 days.Key findingTissue and plasma Se concentrations showed significant changes among non-pregnant, pregnant, and lactating rats. The peak corresponding to selenoprotein P (Sel P) in serum of pregnant rats was reduced. The concentration of 77Se originating from SeMet was higher than those of 76Se from selenite and 78Se from selenate in the stomach content of pups.SignificanceInorganic Se species are more preferably transformed into Sel P than SeMet, and Sel P is effectively incorporated into placenta during pregnancy. On the other hand, SeMet is a more efficient Se source than inorganic Se species during lactation.