Transvaginal aspiration, oocyte maturation and production of blastocysts and a pregnancy via ICSI in an endangered breed: Baudet du Poitou donkey.

ABSTRACT

Two Poitou donkey jennies were presented for clinical oocyte recovery and embryo production via intracytoplasmic sperm injection (ICSI). Both jennies underwent transvaginal ultrasound-guided follicle aspiration on two occasions. Recovered oocytes were held overnight then placed into maturation culture, using standard methods for mare oocytes. On the first replicate for both jennies, the oocytes were divided into two groups; one group was denuded and examined at 30 h culture (standard culture duration for mare oocytes) and the second was denuded and examined at 36 h culture. No oocytes with polar bodies were observed at either time. The oocytes were maintained in maturation culture until 46 h, at which time oocytes with polar bodies were observed. Semen was then prepared; oocytes underwent ICSI approximately 48 h after being placed into maturation culture. On the second replicate for both jennies, oocytes were cultured for maturation for 42 h, then denuded and subjected to ICSI at 46 h. Sperm preparation, injection and embryo culture were performed as for mare oocytes. Blastocyst rates per injected oocyte were 8/19 (42 %) overall, being 4/12 and 4/7 for the first and second TVAs, respectively. Blastocysts were vitrified. Three blastocysts were warmed and transferred to Poitou donkey jenny recipients. One embryonic vesicle was visualized on ultrasonography on embryo Day 12, which increased in size on Day 13 but was not present when examined on Day 14. These results demonstrate that oocyte recovery and ICSI are efficient for production of Poitou donkey blastocysts. To the best of our knowledge, this is the first report of production of blastocysts via ICSI in the Poitou donkey, and the first report of transfer of ICSI-produced embryos in the donkey. Further work is needed on factors affecting pregnancy after embryo transfer in the donkey.