AN OVERVIEW ON CRYOPRESERVATION AND THAWING METHODS OF RABBIT EMBRYOS USED IN EMBRYO TRANSFERE. | ||||
| Journal of Animal and Poultry Production | ||||
| Article 9, Volume 33, Issue 3, March 2008, Page 1895-1907 PDF (587.92 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jappmu.2008.217769 | ||||
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| Authors | ||||
| A. M. Hussein,1; E. Abdel-Khalek2; E. M.E. El-Siefy1; M. M. El-Baz1; M. A. El-Sherbieny1; S. A. Sweify1 | ||||
| 1Anim. Prod. Res. Institute, Agric. Res. Center. | ||||
| 2Anim. Prod. Dept., Fac. Agric., Mansoura University. | ||||
| Abstract | ||||
| To defined the differences in ability of NZW rabbit embryos to survive with different freezing methods (vitrification, step wise and direct methods), donor does were i.m. injected with 75 unit from PMSG 72 h before mating and embryos were collected from slaughtered does 72 h after natural mating. Each preservation method was followed by special thawing method, or by one method (thawing of direct method). After thawing, embryos were in vitro cultured in TCM-199 for three days and embryo characteristics were measured. Results revealed that during cryostorage, mucin coat (MC) was thicker (P<0.05) for vitrification and direct methods than that for step wise method (111 and 114 vs. 104.8 µm, respectively). Thickness of zona pellucid (ZP) was thicker (P<0.05) for step wise and direct methods than that for vitrification method (23.9 and 23.9 vs. 21.8 µm, respectively). However, diameter of intrazonal (IZ) and total embryo (TE) was not affected significantly by preservation method. Only, thickness of MC and ZP reduced (P<0.05) post- than pre-preservation. Post thaw embryo recovery rate was higher (P<0.05) in direct method than vitrification and step wise methods (100% vs. 91.3 and 90%, respectively). Up to the 2nd day of culture, direct method resulted in the highest (P<0.05) viability rate, followed by step wise, while vitrification showed the lowest values. At the 3rd day of culture, step wise method showed the best (P<0.05) viability rate; followed by direct method, while vitrification still to be the lowest. Viability rate of embryos after preservation by three methods, thawed by one method, and in vitro cultured at three successive days show that, direct preservation method resulted in significantly (P<0.05) the highest viability rate (100%), followed by step wise (71.4%), while vitrification showed the lowest values (57.1%). No viable embryos were obtained on the 3rd day of culture with vitrification method and 85.7% of thawed embryos were examined in hatched blastocyst stage with direct method on the 3rd culture day versus 28.6% with step wise method. As affected by culture day after thawing, thickness of MC and diameter of IZ and TE increased (P<0.05) and thickness of ZP decreased (P<0.05) by progressing culture day. In conclusion, cryostorage of embryos recovered from superovulated rabbits after 72 of mating could be carried out successfully by direct method without harmful effects on embryo characteristics, yielded the highest number of good quality embryos on thawing and supported the highest in vitro development of embryos to hatched blastocyst stage. | ||||
| Keywords | ||||
| Rabbit; embryo characteristics; vitrification; step wise; direct method; viability rate | ||||
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