Undernutrition reduces the oviductal mRNA expression of progesterone and oestrogen receptors in sheep

The effect of undernutrition on the oviductal mRNA expression of oestrogen and progesterone receptors (ERα and PR) determined by a solution hybridisation assay in sheep was investigated. Adult ewes were fed either 1.5 (C) or 0.5 (L) times their maintenance requirements and were slaughtered on day 5 or 14 of a synchronised oestrous cycle (day 0 = oestrus). In the oviduct ipsilateral to the corpus luteum, Group L presented lesser concentrations of ERα mRNA than Group C on day 5 (P < 0.05), and lesser PR mRNA concentrations on both days (P < 0.05). No effect of undernutrition was observed in the contralateral oviduct, and there was no difference in transcripts concentrations between days 5 and 14. The lesser sensitivity of the oviduct to ovarian steroids found in undernourished ewes could compromise the embryo environment and partly explain the retarded development reported in embryos collected from nutritionally restricted ewes.