In several species, placentation involves the presence of two different membranes responsible for maternal-fetal exchanges: the yolk sac and the chorioallantoic placenta. The yolk sac plays important roles in embryonic survival, mainly during the early stages of gestation. In bovine, it is a transitional membrane that is present until day 50-70 of pregnancy. Herein, we evaluated the morphological and molecular aspects of the yolk sac of bovine embryos during 24 to 52 days of gestation.
The yolk sac is an embryonic membrane that is essential for the embryo’s initial survival in many mammals. It also plays an important role in the production of proteins necessary for development. We studied proteins of the yolk sac in bovine embryos at up to 40 days of gestation. We examined the yolk sac of 17 bovine embryos at different gestational periods, measuring α-fetoprotein, α-1-antitrypsin, and transferrin. This experiment was carried out by Western blot technique, associated with electrophoresis on a 6% sodium dodecyl sulfate polyacrylamide gel.