Maintenance energy requirement in pregnant rats and net energetic efficiency for fetal growth during late pregnancy.

Abstract

SummaryThe maintenance energy requirement (MEm) of pregnant rats and net energetic efficiency for fetal growth during late pregnancy were examined by regression analysis. Pregnant rats, weighing about 180 g, were fed on 20% casein diet during early-mid pregnancy and then divided into three groups ad libitum-fed, 50% food restricted, or starved. A linear relation between the energy balance (Y, kcal/100g BW/day) and the metabolizable energy intake (X, kcal/100g BW/day) was obtained as Y=0.81 X-14.83 (n: 17, r=+0.99, p<0.001).The X intercept, MEm, was calculated to be 18.31kcal/100g BW/day. Pregnant animals fed ad libitum retained 6.1 and 1.1 kcal of energy daily in their conceptuses and their own body, respectively, during late pregnancy. Assuming that the net efficiency of maternal energy deposition is equal to that for size and age-matched nonpregnant rats, the net energetic efficiency for fetal growth was calculated to be 82%. This value was very close to the net efficiency for weanling rats reported previously, suggesting that the net energetic efficiency for maximum growth in well-nourished rats is about 82%.

Glutathione and Related Enzyme Activity in the 11-Day Rat Embryo, Placenta and Perinatal Rat Liver

“…The placenta is a very important organ for the mother-fetus transfer of nutrients [21,22], Its main role in this transfer is observed when the fetal growth is maximal and its size is near final maturity [23]. The lack of changes in both GSH and GSSG con centration found in placental extracts during rat pregnancy contrasts wiht the rise of both GSHpx and GSSG-R activities in the pla centa as gestation progresses.…”