Reprod. Nutr. Dev.
Volume 43, Number 1, January-February 2003
|Page(s)||1 - 15|
Materno-foetal exchanges and utilisation of nutrients by the foetus: comparison between speciesMarie-Christine Père
Institut National de la Recherche Agronomique, Unité Mixte de Recherches sur le Veau et le Porc, 35590 Saint-Gilles, France
(Received 25 May 2002; accepted 26 December 2002)
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.
Key words: materno-foetal exchange / mammal / carbohydrate / fatty acid / amino acid
Correspondence and reprints: Marie-Christine Père
© INRA, EDP Sciences 2003