Fertility rates following the transfer of ovine embryos cryopreserved using three protocols

Bettencourt, E.M.; Bettencourt, C. M. V.; Silva, João Chagas e; Ferreira, Paulo Michel Pinheiro; Matos, Claudino Pereira; Romão, R.; Rocha, António

doi:10.1016/j.smallrumres.2009.02.011

Cited by 9 publications

(11 citation statements)

References 16 publications

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“…Embryos produced in vitro or manipulated in some manner (e.g., biopsied or bisected) usually yield lower pregnancy rates. Under optimal conditions, pregnancy rates obtained after transfer of frozen-thawed in vivo derived embryos is typically 60-70% in cattle 6,7 , 65-75% in sheep 8,9,10,11 , and 60-70% in goats 12,13,14,15 . Similarly, pregnancy rates obtained after transfer of frozen-thawed in vitro produced embryos is typically 40-50% in cattle 6,16 , 25-35% in sheep 17 , and 30-40% in goats 18 .…”

Section: Representative Resultsmentioning

confidence: 99%

Cryopreservation of Preimplantation Embryos of Cattle, Sheep, and Goats

Youngs¹

2011

JoVE

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Preimplantation embryos from cattle, sheep, and goats may be cryopreserved for short-or long-term storage. Preimplantation embryos consist predominantly of water, and the avoidance of intracellular ice crystal formation during the cryopreservation process is of paramount importance to maintain embryo viability. Embryos are placed into a hypertonic solution (1.4 -1.5 M) of a cryoprotective agent (CPA) such as ethylene glycol (EG) or glycerol (GLYC) to create an osmotic gradient that facilitates cellular dehydration. After embryos reach osmotic equilibrium in the CPA solution, they are individually loaded in the hypertonic CPA solution into 0.25 ml plastic straws for freezing. Embryos are placed into a controlled rate freezer at a temperature of -6°C. Ice crystal formation is induced in the CPA solution surrounding the embryo, and crystallization causes an increase in the concentration of CPA outside of the embryo, causing further cellular dehydration. Embryos are cooled at a rate of 0.5°C/min, enabling further dehydration, to a temperature of -34°C before being plunged into liquid nitrogen (-196°C). Cryopreserved embryos must be thawed prior to transfer to a recipient (surrogate) female. Straws containing the embryos are removed from the liquid nitrogen dewar, held in room temperature air for 3 to 5 sec, and placed into a 37°C water bath for 25 to 30 sec. Embryos cryopreserved in GLYC are placed into a 1 M solution of sucrose for 10 min for removal of the CPA before transfer to a recipient (surrogate) female. Embryos cryopreserved in EG, however, may be directly transferred to the uterus of a recipient.

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Section: Representative Resultsmentioning

confidence: 99%

Cryopreservation of Preimplantation Embryos of Cattle, Sheep, and Goats

Youngs¹

2011

JoVE

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“…Despite the increased efficiency of in vivo embryo production in the last years, there are still some problems to be solved. These problems are mainly related to the great variations observed in the ovarian response, fertilization rates, and embryo quality of hormonally stimulated ewes [9,35,51,52].…”

Section: In Vivo Embryo Productionmentioning

confidence: 99%

“…Multiple ovulation is mainly acquired using FSH, although some programs still use equine chorionic gonadotrophin (eCG) alone or associated with FSH [52,[64][65][66]. Despite the increase in the ovulation rate, the number of embryos obtained with eCG is often lower than expected.…”

Section: Estrus Synchronization and Superovulation Programsmentioning

confidence: 99%

“…The short half-life of FSH implies, however, a 12-hour interval of repeated administration for a period of 4 days [69]. FSH may be of porcine (pFSH) [66,70] or ovine (oFSH) source [52,66,71]. Usually, the treatment begins 72 hours before the withdrawal of exogenous progesterone.…”

Section: Estrus Synchronization and Superovulation Programsmentioning

confidence: 99%

“…Whereas slow freezing tries to differentiate the cooling rate in sequential steps of freezing, vitrification increases the freezing speed by reducing volume, thus minimizing ice formation. These techniques were compared using in vivo-derived or IVP embryos in sheep [14,52,153] or bovine [154]. Bettencourt et al [52] described no differences in lambing or embryo survival rates among slow freezing, conventional vitrification, and vitrification in OPS in in vivo-derived embryos.…”

Section: Cryopreservation Of Sheep Embryosmentioning

confidence: 99%

See 2 more Smart Citations

Cryopreservation of Sheep Produced Embryos – Current and Future Perspectives

Romão¹,

Marques²,

Bettencourt³

et al. 2016

Insights From Animal Reproduction

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Due to economical and scientific limitations, sheep embryo reproductive technologies are less commercially applied than in other animal species. However, it is very clear that, in the near future, those techniques are expected to have a central role in animal production as a consequence of genetic and reproductive demands. One drawback is that results obtained after sheep embryo cryopreservation are unattractive for commercial purposes. It is expected that a successful cryopreservation of sheep embryos can push forward all other reproductive biotechnologies in this species, such as multiple ovulation and embryo transfer (MOET), artificial insemination, or in vitro production of embryos. This paper tries to discuss the current and future perspectives of cryopreservation of in vivo-and in vitro-produced sheep embryos concerning advantages and limitations for its practical use and possible solutions for improving methods to allow a higher survival rate of cryopreserved embryos.

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Long-term cryopreservation had no adverse effect on viability of embryos and their offspring in sheep

Yao

et al. 2012

Animal Reproduction Science

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Fertility rates following the transfer of ovine embryos cryopreserved using three protocols

Cited by 9 publications

References 16 publications

Cryopreservation of Preimplantation Embryos of Cattle, Sheep, and Goats

Cryopreservation of Preimplantation Embryos of Cattle, Sheep, and Goats

Cryopreservation of Sheep Produced Embryos – Current and Future Perspectives

Long-term cryopreservation had no adverse effect on viability of embryos and their offspring in sheep

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