122. PRODUCTION OF EMBRYOS IN SUPEROVULATED EWES USING FROZEN–THAWED, SEX-SORTED AND REFROZEN–THAWED SPERM
K. H. Beilby A , Y. B. Kaurivi A , W. M. C. Maxwell A , G. Evans A , S. P. De Graaf A and C. G. Grupen AVeterinary Science, The University of Sydney, Camperdown, NSW, Australia.
Reproduction, Fertility and Development 22(9) 40-40 https://doi.org/10.1071/SRB10Abs122
Published: 6 September 2010
Abstract
Flow cytometric sex-sorting of sperm that has previously been cryopreserved allows sex-sorting technology to be applied more widely. While offspring have been produced following artificial insemination of synchronised ewes with frozen-thawed, sex-sorted and refrozen-thawed (FSF) sperm (1), the fertility of FSF-sperm in superovulated ewes has not been reported. The aim of this study was to determine the effect of cryopreservation prior to sperm sex-sorting and freezing on embryo production in superovulated ewes. Several ejaculates from 2 rams were either frozen-thawed, then sex-sorted and re-frozen (FSF X- and Y-chromosome enriched sperm), or immediately sex-sorted before freezing (SF X- and Y-chromosome enriched sperm). A portion of each ejaculate was also cryopreserved without sex-sorting (control). Thirty-one ewes were superovulated and inseminated (15 ×106 sperm per insemination dose) with either SF X, SF Y, FSF X, FSF Y or control sperm as previously described (2). Embryos were recovered 6 d after insemination and assessed. The superovulatory response (mean number of corpora lutea per ewe: 11.8 ± 1.3) and the embryo recovery rates (72.0 ± 5.9%) did not differ significantly among the groups. The fertilisation rates tended to differ (P=0.068) as a result of sperm treatment (control: 33%; SF: 54%; FSF: 18%) and were unaffected by sperm sex (X: 33%; Y: 37%). Of the embryos that were recovered, those derived from FSF-sperm were predominantly at the blastocyst stage (65%), whereas those derived from SF-sperm were evenly distributed among the blastocyst (30%), morula (38%) and arrested (32%) stages, suggesting that fertilisation lifespan of SF-sperm was greater than that of FSF-sperm. A greater proportion of embryos derived from Y-sperm were at the blastocyst stage compared with embryos derived from X-sperm (53% vs. 26%; P < 0.05). This study is the first to demonstrate that FSF-sperm is capable of fertilising oocytes of superovulated ewes.
(1) de Graaf et al (2007) Theriogenology 67: 391–8.
(2) de Graaf et al (2007) Theriogenology 67: 550–5.
