Maternal undernutrition during gestation can lead to decreased fetal growth, decreased uteroplacental blood flow, and changes in nutrient supply to the fetus. However, it is unclear how the timing (mid-gestation vs. late-gestation) and duration (40 d vs. 80 d) of nutrient restriction influence nutrient supply to the fetus during mid- to late-gestation. Pregnant ewe lambs fed a pelleted diet to meet 100% of nutritional requirements or 60% of nutritional requirements during mid-gestation alone (days 50 to 90) or during mid- and late-gestation (days 50 to 130). At the end of mid-gestation and late-gestation, the net nutrient supply between the maternal, placental, and fetal compartments was measured. The results indicated that the timing of nutrient restriction influenced the net nutrient supply to the fetus but, the duration of nutrient restriction did not. Nutrient restriction during mid-gestation increased glucose to the fetus but nutrient restriction during late-gestation decreased glucose to the fetus. The opposite response occurred for fetal essential amino acid supply where nutrient restriction during mid-gestation decreased essential amino acid supply to the fetus but increased for several essential amino acids during late-gestational nutrient restriction. The timing of maternal undernutrition during mid- to late-gestation can affect the amount of nutrients delivered to the fetus and thus, could potentially impact postnatal growth and development.

Read the full article in the Journal of Animal Science.