Nutrient uptake of the uterus during the last third of pregnancy in sows: Effects of litter size, gestation stage and maternal glycemia.

Effects of litter size, pregnancy stage, and glycemia level on uterine uptake of energetic nutrients were studied on multiparous sows left intact (CTR; n=6) or subjected to unilateral oviduct ligation (LIG; n=6). A jugular vein, a carotid artery, and the main vein draining one uterine horn were catheterized. A blood flow probe was fitted around the artery irrigating that horn. A meal test and two glucose infusion tests (1.15 or 2.30g glucose·(100kg BW)-1 min-1 ) were performed at 79, 93, and 106 d of pregnancy. Number of fetuses in the measured uterine horn was lower (3.7 vs. 8.0, P<0.001) and newborn piglets were heavier (1.71 vs. 1.31kg, P=0.04) in the LIG than in the CTR sows. Treatment did not affect uterine blood flow (UBF), but UBF/fetus was greater for the LIG treatment (0.57 vs. 0.32L/min, P=0.003). Glucose and lactate uterine uptakes were never significantly affected by treatment. During both tests, uterine uptake of glucose/fetus was greater in the LIG sows, which was associated with greater growth rate of their fetuses. Glucose and lactate uterine uptakes per fetus increased with glucose infusion level (P=0.03) and stage of pregnancy (P=0.04). Extraction coefficient of glucose decreased during infusion (P<0.001). Uptakes of NEFA and triglycerides were small and decreased during hyperglycemia. Glucose and lactate uptakes increased with pregnancy stage due to increased uterine blood flow. Altogether, the nutrient uptake per fetus was greater in the sows with few fetuses.