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

Abstract

-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 Blood samples were withdrawn at 105 days of pregnancy from 10 min before and up to 90 min after feeding of a 2.5-kg meal.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

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

“…Figure 3 also shows that as maternal glycaemia increases, foetal glycaemia and materno-foetal differences increase. This is the case after meal intake in the pig where the slope of the relationship between foetal and maternal glycaemia is about 0.30 [13]. In contrast, fasting [14,15] or insulin perfusion [16] in sheep decreases glucose umbilical uptake.…”

“…However, by using hyperinsulinaemic euglycaemic clamps in Foetal uptake and utilisation of nutrients 3 Figure 3. Relationship between maternal and foetal glycaemia in several species (from Battaglia and Meschia [21] and (1) Père [13]). …”

“…Lactate is produced from glucose by the placenta under aerobic conditions and is carrier-mediated transferred to the foetus [21]. Similarly to glucose, lactate concentration in foetal pig blood increases after the meal [61], suggesting a higher lactate production in these conditions. The contribution of lactate to foetal metabolism amounts to one-third to one-half that of glucose in most species [17].…”

“…In species with a less permeable placenta, the levels of FFA and ketoacids in foetal blood are low and not correlated with the maternal levels [61,69]. Their uptake does not represent a significant energy source for the gravid uterus of sheep [70], cows [64], mares [64] or sows [10,61].…”

Evaluación del perfil metabólico lipídico en cerdas gestantes y su relación con la nutrición fetal

“…Cantidades limitadas de ácidos grasos libres son absorbidos por el útero y atraviesan la barrera placentaria, principalmente en condiciones de ayuno. Asimismo, se ha encontrado que las concentraciones de NEFA son menores en el plasma fetal que en el plasma maternal (19).…”