title: Production of lambs after the transfer of fresh and cryopreserved in vitro produced embryos from prepubertal lamb oocytes and unsorted and sex-sorted frozen-thawed spermatozoa.
abstract: Cumulus-oocyte complexes from hormone-stimulated 3-4-week-old (n=43) and 6-7-week-old (n=12) prepubertal lambs were matured in vitro and incubated with unsorted, or X- or Y-spermatozoa separated with a high-speed cell sorter (SX MoFlo)frozen-thawed. Presumptive zygotes were then cultured to the blastocyst stage, and transferred to recipients fresh or after cryopreservation (frozen). Oocyte cleavage was higher (p <0.05) with unsorted (515/926, 55.6%) than X- or Y-spermatozoa (261/672, 38.8% and 229/651, 35.2%, respectively) and blastocyst formation (% zygotes) by Day 9 of in vitro culture was lower (p <0.05) for X- (102/261, 39.1%) than unsorted spermatozoa (249/515, 48.3%), but did not differ between Y-spermatozoa (103/229, 45.0%) and unsorted spermatozoa, or between X- and Y-spermatozoa (p >0.05). For fresh embryos, survival to term was 50.0% (3/6) for unsorted, 0.0% (0/6) for X- and 16.7% (1/6) for Y-spermatozoa-derived embryos (p >0.05), and for frozen embryos was 4.0% (2/50) for unsorted, 9.1% (2/22) for X- and 2.9% (1/34) Y-spermatozoa-derived embryos (p >0.05). Of the two lambs born from X-spermatozoa-derived embryos, one was female (50%), and from the two Y-spermatozoa-derived lambs, both were male (100%), demonstrating that lambs can be produced after the transfer of fresh and cryopreserved IVP embryos derived from prepubertal lamb oocytes and frozen-thawed sex-sorted sperm.
authors.affiliation: Faculty of Veterinary Science, Centre for Advanced Technologies in Animal Genetics and Reproduction (ReproGen), The University of Sydney, Sydney, NSW, Australia. kmorton@vetsci.usyd.edu.au
authors.forename: K M
authors.initials: KM
authors.lastname: Morton
authors.forename: S L
authors.initials: SL
authors.lastname: Catt
authors.forename: F K
authors.initials: FK
authors.lastname: Hollinshead
authors.forename: W M C
authors.initials: WM
authors.lastname: Maxwell
authors.forename: G
authors.initials: G
authors.lastname: Evans
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000502:physiology; D002469:Cell Separation / Q000662:veterinary; D015925:Cryopreservation / Q000662:veterinary*; D004624:Embryo Transfer / Q000662:veterinary*; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary*; D005434:Flow Cytometry / Q000662:veterinary; D005865:Gestational Age; D008297:Male; D011247:Pregnancy; D011256:Pregnancy Outcome; D012662:Semen Preservation / Q000662:veterinary*; D012732:Sex Determination Analysis / Q000662:veterinary*; D012741:Sexual Maturation; D012756:Sheep; D013094:Spermatozoa; D046509:Tissue Culture Techniques