Physiology Symposium II: Reproductive Fluids in Fertilization and Early Embryonic Development Summary
By: Dr. Emily Taylor, Purdue University, West Lafayette Indiana
Female Reproductive Fluids and Epigenetics, Dr. Sebastian Canovas – University of Murcia
Dr. Canovas began his presentation by giving a brief overview of how reproductive fluids impact the developing embryo. Current in vitro fertilization studies have observed transcriptional and epigenetic differences in embryos compared to those fertilized in vivo, potentially resulting in long-term phenotypic consequences for the individual. Dr. Canovas discussed the need for reproductive fluid supplementation in culture media to imitate in vivo fertilization's physiological conditions.
Research was presented that suggested positive impacts in both swine and bovine embryos when natural reproductive fluids were supplemented to media during in vitro fertilization. More specifically, in pigs, the modulation of capacitation-associated events, sperm-zona binding, and polyspermy control were impacted. Blastocyst rate, expression of altered genes, and survival during embryo transfer were affected in cows. In addition, Dr. Canovas suggested a sex-specific effect when supplementation of reproductive fluids was used during in vitro fertilization. Data presented indicate that sex did impact DNA methylation.
Sperm Retention, Storage and Release from the Oviduct: A story of Sugars, Steroids, and Channels, Dr. David Miller – University of Illinois. Urbana - Champaign
Dr. Miller began his presentation by discussing the importance of synching estrous with artificial insemination to maximize conception rates. While all females store sperm cells in the reproductive tract, which will aid in conception during artificial insemination, the length of storage time varies greatly among species. Dr. Miller suggests using what we know about the extended time of sperm storage of other species to potentially increase the length of sperm storage in cattle and swine.
Research presented has shown that sperm cells migrate towards grooves within the oviduct, dictating travel patterns. This movement is affected by peristaltic waves, fluid flow and viscosity, movement along surfaces, and adhesion to the epithelium. There have been specific glycans in the oviduct identified that bind to receptors on the sperm cells, extending the lifespan of sperm. Once the oocyte is present, the cumulus-oocyte complex secretes substances such as progesterone that release these sperm cells from the isthmus. This data provides clues about how sperm lifespan is extended during storage.
Large Offspring Syndrome: Effects of in vitro Production on Embryo Epigenetics and Development, Dr. Rocio Melissa Rivera – University of Missouri
Dr. Rivera began discussing assisted reproductive technologies and how large offspring syndrome has resulted from in vitro fertilization. Large offspring syndrome is a congenital overgrowth with phenotypic characteristics like; somatic overgrowth, abdominal wall defects, large organs, breathing difficulties, skeletal defects, hypoglycemia, abnormal placentas, difficulty suckling, and perinatal death. Not only does large offspring syndrome cause negative impacts on the calf, but the dam may also be affected. This results in financial and reputation losses for a producer.Dr. Rivera has identified similarities between large offspring syndrome and a congenital overgrowth syndrome in humans known as Beckwith Wiedemann Syndrome, also known as a loss-of-imprinting condition. Therefore, research was presented describing how large offspring syndrome was also a loss-of-imprinting condition, where multi loci are affected. Currently, Dr. Rivera is working to determine if large offspring syndrome can be identified during pregnancy through ultrasonography at d55 or maternal blood at d105.
An unedited recording of the symposium is now available on the meeting website.