Abstract: 267

TRANSFER OF EQUINE GAMETES TO RABBIT OVIDUCTS: AN APPROACH TO PRODUCE EQUINE EMBRYOS.

F. Landim-Alvarenga¹ , M. Alvarenga¹ , E. Carnevale¹ , S. Boyazoglu¹ , R. Ramirez¹ , George Seidel Jr.^{1 *}, Edward Squires^{1 *}
Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins, Colorado ¹

Because of the poor results obtained with in vitro fertilization and in vitro culture of equine embryos during early stages of development, we transferred equine gametes to rabbit oviducts. Oocytes were collected by ultrasound–guided transvaginal aspiration (TVA) from pregnant mares between 50–60 days of gestation. GROUP 1: Transvaginal aspiration of follicles > 10mm was repeated six times in each mare (n=12) at 10 day intervals. Oocytes were matured in vitro for 36 to 40 hours in Hepes TCM–199 + 10% FCS, E₂ and gonadotrophins at 39°C in 5% CO₂ in air. GROUP 2 (Control): Bovine oocytes from slaughterhouse ovaries were aspirated from 2–7mm antral follicles. Selected oocytes were matured as described for Group 1 except only for 24 hours. Fresh bull and horse sperm were washed using a Percoll gradient. For capacitation bovine sperm were incubated for 1 hr in Fert–Talp + PHE at 37°C; equine sperm were incubated for 5 min with A23187 (100nM) in BGM3. Seven adult female Rabbits were used as recipients. Equine gametes were transferred to the right oviduct and bovine gametes were transferred to the left oviduct; 4 days after the transfer, rabbits were euthanized. We recovered 58 of 87 bovine ova transferred and 41 of 51 equine ova transferred; 72.4% of bovine and 51.2% of equine were cleaved or had 2 pronuclei present. The number of morulae collected was 13 (22.4%) for cattle and 6 (14.6%) for hoses. We conclude that bovine and equine oocytes can be fertilized in the rabbit oviduct. While this is the first report of successful fertilization and embryo development of equine ova in a heterologous recipient, the number of morulae formed was low.

    This abstract is being presented on Monday, August 2 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.