Reproduction Abstracts

Introduction: This study compared uterine and placental expression of genes implicated in placental attachment and angiogenesis in two prolific (hLW and MS) and one control (LW-LD) pig breeds.

Methods: Placental and endometrial tissues supplying the smallest and a normal-sized foetus within the same litter were collected from five LW-LD, five hLW and four MS gilts on days 40–45 of pregnancy. RNA was isolated and qPCR for SPP1, VEGFA, HPSE, HIF1A and ACP5 performed. Normalised relative expression data were analysed by a mixed model in SAS, accounting for the common maternal environment.

Results and discussion: SPP1, VEGFA, HPSE, HIF1A and ACP5 mRNA was present in all tissues studied but, with the exception of ACP5, expression levels varied with breed and foetal size. Endometrial expression of VEGFA, HPSE and HIF1A was higher in LW-LD compared to either MS (P=0.002; P=0.05 and P=0.001, respectively) or hLW (P=0.0011; P=0.0001 and P<0.0001, respectively). Placental SPP1 expression was higher in hLW than in LW-LD (P=0.03) and, VEGFA expression was higher in placentas supplying normal foetuses in hLW than in MS (P=0.04). Expression of SPP1, VEGFA, HPSE and HIF1A in LW-LD and MS and of HPSE and HIF1A in hLW was higher in endometrium supplying the smallest compared to normal foetuses. Placental gene expression mirrored differences in endometrial gene expression with the exception of SPP1, which was higher in placentas supplying normal foetuses of all breeds and HPSE which was higher in placental tissue supplying normal hLW foetuses. Breed and foetal size differences in gene expression support their role in foetal growth and prenatal survival.

Funding: COST Action FA0902, BPEX and BBSRC