Embryo development rates after transfer of oocytes matured in vivo, in vitro, or within oviducts of mares

Scott, Tony; Carnevale, E.M.; Maclellan, L.J.; Scoggin, C.F.; Squires, E.L.

doi:10.1016/s0093-691x(01)00438-1

Cited by 48 publications

(34 citation statements)

References 32 publications

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“…In this respect, oocytes matured in vivo give rise to much better pregnancy rates after transfer to the oviduct of a recipient mare than those matured in vitro (e.g. 82 vs 9%; Scott et al 2001), while the blastocyst formation rates for equine oocytes matured in vitro and fertilized by ICSI are much better if the presumptive zygotes are transferred to the oviduct of a mare than if they are cultured in vitro (36 vs 0-20%: Choi et al 2004). …”

Section: Blastocyst Rate (% Of Injected Oocytes)mentioning

confidence: 99%

Effect of cumulus morphology and maturation stage on the cryopreservability of equine oocytes

Tharasanit¹,

Colleoni²,

Lazzari³

et al. 2006

Reproduction

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Oocyte cryopreservation is a potentially valuable way of preserving the female germ line. However, the developmental competence of cryopreserved oocytes is presently poor. This study investigated whether the morphology of the cumulus complex surrounding an immature equine oocyte and/or the oocyte's stage of maturation affect its cryopreservability. Compact (Cp) and expanded (Ex) cumulus oocyte complexes (COCs) were vitrified either shortly after recovery (germinal vesicle stage, GV) or after maturation in vitro (IVM); cryoprotectant-treated and -untreated non-frozen oocytes served as controls. In Experiment I, oocytes matured in vitro and then vitrified, or vice versa, were examined for maturation stage and meiotic spindle quality. Cp and Ex COCs vitrified at the GV stage matured at similar rates during subsequent IVM (41 vs 46% MII), but meiotic spindle quality was better for Cp than Ex (63 vs 33% normal spindles). Vitrifying oocytes after IVM resulted in disappointing post-warming spindle quality (32 vs 28% normal for Cp vs Ex). In Experiment II, oocytes from Cp and Ex COCs vitrified at the GV or MII stages were fertilized by intracytoplasmic sperm injection (ICSI) and monitored for cleavage and blastocyst formation. Oocytes vitrified prior to IVM yielded higher cleavage rates (34 and 27% for Cp and Ex COCs) than those vitrified after IVM (16 and 4%). However, only one blastocyst was produced from a sperm-injected vitrified-warmed oocyte (0.4 vs 9.3% and 13% blastocysts for cryoprotectant-exposed and -untreated controls). It is concluded that, when vitrification is the chosen method of cryopreservation, Cp equine COCs at the GV stage offer the best chance of an MII oocyte with a normal spindle and the potential for fertilization; however, developmental competence is still reduced dramatically. Reproduction (2006) 132 759-769

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Section: Blastocyst Rate (% Of Injected Oocytes)mentioning

confidence: 99%

Effect of cumulus morphology and maturation stage on the cryopreservability of equine oocytes

Tharasanit¹,

Colleoni²,

Lazzari³

et al. 2006

Reproduction

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“…In the same laboratory, use of non-transported ovaries for IVM and oocyte transfer resulted in a pregnancy rate of 10% (4/40) [8]. These results suggest that immature equine oocytes from ovaries preserved for one day retained their in vivo developmental competence.…”

mentioning

confidence: 70%

In Vitro Development of Equine Oocytes from Preserved Ovaries after Intracytoplasmic Sperm Injection

Matsukawa

Akagi

Adachi

et al. 2007

Journal of Reproduction and Development

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Abstract. In this study, we evaluated the meiotic competence of equine oocytes from ovaries preserved for one day. We also investigated fertilization, cleavage rate, developmental competence and freezability of equine embryos after intracytoplasmic sperm injection (ICSI). After collection from ovaries, the oocytes were classified into two groups comprised of those having compact cumulus layers (Cp) or those having expanded cumulus layers (Ex). Oocytes with a first polar body were subjected to fertilization by ICSI using frozen-thawed stallion spermatozoa and were then cultured in CR1aa medium. The rates of metaphase II-stage oocytes, normal fertilization and cleavage were not significantly different between the two oocyte categories (38.5, 70.0 and 48.7% for CP and 43.5, 60.0 and 58.8% for Ex, respectively). However, the blastocyst development rate of Ex was significantly (P<0.05) higher than that of Cp (25.5 vs. 7.7%). Three Cp-derived and 12 Ex-derived early blastocysts were cryopreserved using the slow cooling protocol, and all of them developed to hatching blastocysts after thawing. These results suggest that equine oocytes fertilized by ICSI can develop to the preimplantation stage in culture conditions similar to those used in the bovine. Furthermore, the Ex oocytes had higher developmental competence than the Cp oocytes, and the in vitro-produced blastocysts had high viability after freezing and thawing.

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“…In recent studies (Scott et al 2001, embryo development rates were over 80% when mares were inseminated only before oocyte transfer with fresh semen. However, when recipients were inseminated with fresh semen only after oocyte transfer, pregnancies were also obtained (8/14, 57%) (Carnevale et al 2000).…”

Section: Discussionmentioning

confidence: 99%

“…Although oocyte transfer is expensive, it provides a method of studying the process of fertilization, including the interactions of the oocyte, sperm and oviduct. To reduce the expense of transfers, multiple oocytes are often transferred per recipient (Carnevale & Ginther 1995, Carnevale et al 2000, Scott et al 2001 -reducing costs but increasing the effect of an individual recipient on the results. Methods of minimizing the effect of each recipient after oocyte transfer would be valuable for future research.…”

Section: Introductionmentioning

confidence: 99%

Use of parentage testing to determine optimum insemination time and culture media for oocyte transfer in mares

Carnevale

Silva²,

Maclellan³

et al. 2004

Reproduction

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Parentage identification was used to test the developmental competence of oocytes cultured under different conditions and fertilized in vivo after oocyte transfer. Oocytes were collected transvaginally from follicles of estrous mares approximately 22 h after administration of human chorionic gonadotropin. Oocytes were cultured for approximately 16 h in one of three media, with or without addition of hormones and growth factors. Groups of three or four oocytes, cultured in different media, were transferred into the oviduct contralateral to a recipient's own ovulation. Recipients were inseminated with semen from two different stallions at 15 h before and 2.5 h after oocyte transfer. Sixteen days after transfer, embryos were recovered from uteri and submitted for parentage testing. The percentage of oocytes resulting in embryonic vesicles was nearly identical (P > 0.05) for transferred oocytes (32/44, 73%) versus ovulated oocytes of recipients (9/13, 69%). More (P < 0.01) oocytes were fertilized by sperm inseminated before (35/38, 92%) versus after (3/38, 8%) oocyte transfer. Tissue culture medium (TCM)-199 was superior to equine maturation medium I (EMMI; a SOF-based medium) for culturing oocytes (P < 0.05), although addition of hormones and growth factors during culture did not improve (P > 0.05) development of embryos.

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Embryo development rates after transfer of oocytes matured in vivo, in vitro, or within oviducts of mares

Cited by 48 publications

References 32 publications

Effect of cumulus morphology and maturation stage on the cryopreservability of equine oocytes

Effect of cumulus morphology and maturation stage on the cryopreservability of equine oocytes

In Vitro Development of Equine Oocytes from Preserved Ovaries after Intracytoplasmic Sperm Injection

Use of parentage testing to determine optimum insemination time and culture media for oocyte transfer in mares

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