Physiology and Endocrinology: Sperm-Oviduct Interactions in Livestock and Poultry

The mammalian oviduct has long been recognized as an organ essential to the success of reproduction. Bovine, ovine, porcine and equine animal models have offered clear advantages for oviduct study related to gamete physiology, fertilization and early embryo development. Livestock species are amenable to surgical alteration of the reproductive tract, estrous cycle manipulation, gamete cryopreservation, artificial insemination as well as in vitro fertilization and embryo production. Although most reproductive technology developed for livestock was intended to benefit production animal agriculture, these techniques are a treasure trove of tools for researchers to better understand how the oviduct influences gamete function. Oviduct secretions obtained from in vitro tissue cultures or via indwelling oviduct catheters have been used for analyses to define the protein, lipid, carbohydrate, enzyme and electrolyte compositions of the secretions during the estrous cycle or in response to hormone treatment. Oviduct secretions or components purified there from have also been used in in vitro assays to assess their ability to bind to sperm and/or influence on sperm viability, motility, sperm capacitation, the acrosome reaction, sperm-egg binding, egg penetration as well as subsequent embryo development. Compelling data have emerged which show that the composition of secretions differs during the estrous cycle and that their composition differs whether they originate from the ampullar or isthmic regions of the oviduct. These differences in composition are functionally relevant and associated with different responses by sperm. Evidence suggests that oviduct -specific glycoproteins, glycosaminoglycans, carbohydrates, norepinepherine, catecholamines, heat-shock protein and osteopontin are components of the oviductal milieu which have the capacity to modulate sperm function. Continued research on the livestock oviduct will likely unravel the role that specific oviduct secretions have in modulating sperm function and how these modifications ultimately affect fertilization and embryo development.