Pregnancies produced from fertile and infertile stallions by intracytoplasmic sperm injection (ICSI) of single frozen-thawed spermatozoa into in vivo matured mare oocytes.
The use of intracytoplasmic sperm injection (ICSI) for in vitro fertilization of equine oocytes and the developmental potential of these oocytes after transfer to the Fallopian tubes of synchronized mares were examined. Oocytes were aspirated from mature follicles 39 h after injection of a GnRH analogue and transported 190 km at 39 degrees C. Semen from a fertile and an infertile stallion was frozen and prepared for injection. Successfully injected oocytes were transferred surgically into the ampulla of the Fallopian tube either: (i) 4-8 h after semen injection; or (ii) after 24-48 h culture before transfer. Oocytes (n=26) were treated by ICSI: three oocytes fragmented after injection (12%) and eight oocytes were returned for immediate transfer to recipient mares. Of the 15 cultured oocytes, eight (53%) had two polar bodies and cleaved to two-cell embryos 24 h after injection. Pregnancies were identified on day 12-14 after transfer in 4/16 (25%) recipients that had received either transferred embryos (1/8) or freshly injected oocytes (3/8). Two of the four pregnancies did not progress beyond day 30 and two mares gave birth to foals. There were no apparent differences in the establishment of pregnancies from oocytes injected with frozen-thawed spermatozoa from the fertile (3/14) or infertile stallion (1/2).
McKinnon
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AO
Goulburn Valley Equine Hospital, P.O. Box 2020, Shepparton, Victoria 3632, Australia.
Lacham-Kaplan
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O
Trounson
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AO
D000818:Animals; D015925:Cryopreservation / Q000662:veterinary; D004624:Embryo Transfer / Q000662:veterinary; D005260:Female; D006736:Horses / Q000502:physiology*; D007248:Infertility, Male / Q000662:veterinary*; D008297:Male; D009865:Oocytes / Q000502:physiology*; D011247:Pregnancy; D012662:Semen Preservation / Q000662:veterinary*; D020554:Sperm Injections, Intracytoplasmic / Q000662:veterinary*; D013094:Spermatozoa / Q000502:physiology*