Characterization of the placental development in the intra-uterine growth retarded piglet
Résumé
In pig production, the selection of hyperprolific animais has lead to an increased rate of intrauterine growth retarded (IUGR) piglets in litters. This is an important economie issue as these piglets display higher mortality rates, lower growth capacity and lower quality carcasses. The ptrrpose of this work was to investigate placenta!morphology and function during early (45d), mid (71d) and late gestation (112d) in pairs of control and IUGR siblings. Altogetber, 18 pairs were used (N=5, 6 and 7 at 45, 71 and 112 days, respective!y), each pair, but one, being of the same sex. The IUGR piglets were 25%, 33% and 41% lighter than controls. Relative uterine and placenta!proportions of blood vessels, connective tissue and trophoblast were measured by stereology. Placenta! expression of genes involved in fetal growth (IGF2), angiogenesis and vascularization (eNOS, VEGFa, FLTI, KDR), nutrient transport (GLUT3, SNAT2, LPL) and oxidative stress (SODl, SOD2) was measured by RT qPCR. Data were analyzed using Mann-Whitney test (morphometry) and ANOVA (gene expression). Morphometric analysis did not reveal any significant difference according to gestational age nor group. IGF2 expression was significantly increased in IUGR placenta at 71d of gestation (x 1.48, p