Effects on dietary restriction and selenium supply on maternal and fetal tissue selenium distribution, metabolic hormones, and intestinal growth and cellularity.

摘要

Maternal nutrient restriction results in reduced fetal weight, asymmetric fetal organ growth, and poor growth performance and health later in life. Elevated levels of dietary Se have been associated with increased mucosal mass of normal jejunal tissue. If elevated dietary levels of Se increase cell mass or number in healthy tissues, then additional Se may provide a sparing effect on tissues impacted by nutrient depletion. Therefore, the objectives of these studies were to evaluate effects of dietary restriction and selenium supply on maternal and fetal tissue selenium distribution, metabolic hormones, and intestinal growth and cellularity. Maternal dietary restriction to 60% of total intake of controls resulted in reduced (P &le 0.06) fetal and intestinal mass while ewes provided 3 ppm or 15 ppm (supranutritional levels) dietary Se from either organically bound or inorganic sources had similar (P &ge0.39) jejunal mass compared with controls. Providing supranutritional levels of dietary Se resulted in a 76% increase in the total number of proliferating maternal jejunal crypt cells. Ewes restricted to 60% of total intake of controls and offered supranutritional levels of dietary Se (81.5 microg/kg BW daily), from a yeast product, had greater fetal BW, fetal lung, heart, and spleen mass compared with controls. Ewes provided 3 ppm Se had lower T4:T 3 ratios compared with controls, indicating that more T3 may have been available to stimulate metabolism in the nutrient-restricted ewes, thus resulting in more nutrients to partition to the fetus. Selenium tissue accumulation was also greater in ewes provided 3 ppm Se from an organically bound source compared with ewes fed either 3 ppm or 15 ppm from sodium selenate, or controls. Data of these respective studies imply supranutritional levels of Se from sources high in selenomethionine provide a sparing effect on fetal tissues when maternal nutrition is limiting.