Uterine Blood Flow and Nutrient Uptake during Late Gestation in Ewes with Different Number of Fetuses

2001

-Catheters were implanted in 18 gilts at 99 days of pregnancy to study the effects of meal intake on uterine and umbilical uptake of energetic substrates in the conscious pig. Blood samples were withdrawn at 105 days of pregnancy from 10 min before and up to 90 min after feeding of a 2.5-kg meal. Plasma glucose was 2.2 to 2.5 times lower and blood lactate 2 to 3 times higher in the foetus than in the sow. Glucose and lactate increased after the meal. Their umbilical uptake amounted to 0.32 and 0.26 mmol . L -1 , respectively. Fructose was found in large amounts in foetal plasma (4.3 mmol . L -1 ), but it did not seem to be metabolised by the foetus. Meal intake decreased plasma levels of FFA and glycerol in the sows, whereas they increased in the foetuses. A small FFA and glycerol umbilical uptake was recorded (14 and 6 µmol . L -1 , respectively). Most features of the maternofoetal exchanges in the porcine species resemble those of other species, especially ruminants. materno-foetal exchange / energetic substrate / meal intake / pig Résumé -Effets de la prise alimentaire sur les échanges materno-foetaux de substrats énergétiques chez le porc. Des cathéters ont été implantés sur 18 truies à 99 jours de gestation afin d'étudier chez l'animal vigile les effets d'une prise alimentaire sur la capture de substrats énergétiques par l'utérus et le foetus. Des échantillons de sang ont été prélevés à 105 jours de gestation entre 10 min avant et 90 min après la distribution d'un repas de 2,5 kg. La glycémie était 2,2 à 2,5 fois plus faible et la lactatémie 2 à 3 fois plus élevée chez le foetus que chez la mère. Elles augmentaient après le repas. La capture de glucose et de lactate par le foetus était respectivement de 0,32 et 0,26 mmol . L -1 . Les concentrations sanguines de fructose étaient élevées chez le foetus (4,3 mmol . L -1 ), mais ce substrat ne semblait pas métabolisé. La consommation du repas provoquait une diminution des teneurs plasmatiques en AGL et en glycérol des truies alors qu'elles augmentaient chez les foetus. Une faible Reprod. Nutr. Dev. 41 (2001) 285-296 285

Section: Glycerolsupporting

confidence: 75%

Effects of meal intake on materno-foetal exchanges of energetic substrates in the pig

2001

“…In the pig, after an overnight fast, it amounts to 2.29 and 0.90 mmol·L -1 in the foetal umbilical vein and the maternal arterial blood, respectively [11]. A higher lactate level in the uterine vein relative to the artery was demonstrated in several species [10,25,[57][58][59][60], showing a net uptake of lactate by the mother from the uterus. Lactate is produced from glucose by the placenta under aerobic conditions and is carrier-mediated transferred to the foetus [21].…”

Section: Lactatementioning

confidence: 99%

Materno-foetal exchanges and utilisation of nutrients by the foetus: comparison between species

2003

-Several general features of nutrient uptake and utilisation by foetuses are similar among mammalian species. Nevertheless, there are also differences linked mainly to differences in placental permeability. Glucose and lactate are the main energetic substrates of the foetus. In normal conditions, the oxidation of carbohydrates accounts for about 75, 60 and 50% of oxygen uptake in the foetal pig, foal and lamb, respectively, and acetate accounts for about 10% in ruminants. Acidic amino acids are synthesised by the foetus, whereas neutral and basic amino acids are transported from the placenta. As shown by the high urea level in foetal blood, amino acids are partly involved in the oxidative metabolism of foetuses; their contribution is higher in ruminants than in humans, horses and pigs. Fatty acids cross the haemochorial placenta of rodents, rabbits and primates, and are incorporated into the foetal lipids, whereas their uptake by ruminant, pig and horse foetuses is very low.materno-foetal exchange / mammal / carbohydrate / fatty acid / amino acid

“…Reynolds et al [48] reported that UBF was correlated with the number of foetuses per uterine horn. Christenson and Prior [10] found that UBF at 105 days was greater in ewes with triplets than in ewes with twins and tended to be lower in ewes with a single foetus. Ferrell and Reynolds [21] measured a lower UBF in cows with a single foetus than with twin foetuses.…”

Section: Variation Of Ubf With Litter Sizementioning

confidence: 99%

“…5 second half of pregnancy [8,35]. Christenson and Prior [10] reported that UBF increased from 958 to 1 358 mL . min -1 between 105 and 123 days of pregnancy in ewes.…”

Section: Effect Of Number Of Foetuses In the Uterine Hornmentioning

confidence: 99%

Uterine blood flow in sows: effects of pregnancy stage and litter size

Etienne

2000

-Female pigs were assigned to three groups at 94 days of age: a control group (CTR), a group undergoing the ligation and severing of the left oviduct (LIG), and a group undergoing right hysteroovariectomy (HHO). They were inseminated at 307 days of age. At 35 days of pregnancy, an ultrasonic transit time flow probe was implanted around the middle artery of one uterine horn in 33 sows and uterine blood flow was measured during thirteen 24-h periods between 44 and 111 days. Despite large differences in ovulation rate per uterine horn (4.8, 8.3 and 16.9 in the LIG, CTR and HHO groups, respectively), variation of litter size was considerably reduced with advancement of pregnancy (3.0, 6.6 and 10.8 foetuses per uterine horn at 35 days, and 3.0, 5.8 and 4.9 at 112 days (slaughter), respectively). Uterine blood flow increased linearly during pregnancy. It was lower in the LIG sows (0.82 to 1.74 L . min -1. horn -1 from 44 to 111 days) than in the CTR and HHO sows (1.22 to 2.84 and 1.09 to 2.63 L . min -1. horn -1 , respectively). It was more closely related to litter weight than to litter size and amounted to 0.42 L . min -1. kg foetus -1 at 111 days. Uterine blood flow per foetus decreased when litter size increased. It increased from 0.31 to 0.72, 0.26 to 0.60 and 0.20 to 0.43 L . min -1. foetus -1 from 44 to 111 days when there were 2 to 3, 4 to 5, and 6 to 8 foetuses in the uterine horn, respectively. This explains why piglets from large litters are lighter at birth.