Development of in vitro maturation, fertilization and embryo culture in addax (Addax nasomaculatus), an endangered desert antelope

This project was designed to investigate the use and application of domestic cattle technology for in vitro embryo production in addax (Addax nasomaculatus), an endangered species of desert antelope. Specifically, this project: (1) evaluated current estrus synchronization, ovarian stimulation and superovulation protocols, (2) optimized in vitro oocyte maturation, (3) analyzed sperm fertilizing ability in vitro, and (4) evaluated two in vitro culture systems to produce embryos to the blastocyst stage.; Estrus synchronization, ovarian stimulation, and superovulation were monitored using serum hormone analysis and ovarian ultrasonography. Although synchronization and ovarian stimulation were successful, ovulations could not be prevented during stimulation nor induced during superovulation, indicating that control of ovulation in this species differs from that in domestic cattle.; To study the timing of oocyte in vitro maturation, oocytes were collected from hormonally stimulated females and assessed for nuclear maturation after incubation. The results suggest addax oocytes mature approximately four hours more slowly than those from domestic cattle and should be fertilized between 26 and 28 hours of incubation.; To test whether addax sperm can undergo capacitation and acrosome reaction in vitro, and to determine the best technique to separate motile sperm, semen was collected and used fresh or frozen, thawed. Sperm were separated and used to fertilize domestic cattle oocytes. Addax sperm were able to fertilize domestic cattle oocytes, indicating they underwent capacitation and acrosome reaction. Although not significantly different from the other two separation techniques, swim-up was used for fertilizing addax oocytes with frozen, thawed sperm.; To compare the use of semi-defined culture media and co-culture for the production of in vitro-derived addax embryos, oocytes were collected from hormonally stimulated females, matured, fertilized, and cultured. Although an apparent developmental block occurred at the eight-cell stage, addax embryos developed to the morula and blastocyst stages in both culture treatments.