Cytoplast source influences development of somatic cell nuclear transfer (SCNT) embryos in vitro but not their development to term after transfer to synchronized recipients in dromedary camels (Camelus dromedarius)

Abstract

Studies were conducted to evaluate the adequate time for exposure of donor nucleus to oocyte cytoplast before its activation and the effect of oocyte source on the development of SCNT embryos in camels. A higher number of embryos cleaved and developed to blastocyst stage (P < 0.05) when couplets were activated between 1 and 2 h-than that of those activated at 0.5 h or more than 2 h post-fusion. A reduced number of reconstructed embryos cleaved (55.2 ± 7.6%) and developed to the blastocyst stage (20.5 ± 5.5%) when in vitro matured oocytes collected from the slaughterhouse were used as donor cytoplasts, compared to in vitro (71.3 ± 1.3 and 36.7 ± 7.3%) or in vivo matured (91.7 ± 8.3 and 35.4 ± 6.0%) oocytes obtained from live animals (P < 0.05), respectively. However, no differences were observed between the different types of oocyte sources on the establishment of pregnancies and delivery of offspring's. In conclusion, couplets activated 1–2 h post-fusion had higher in vitro developmental potential and oocytes collected from live animals were better in supporting the cleavage and blastocyst production in vitro than oocytes collected from slaughterhouse ovaries, however, all sources of oocytes can be utilized as donor cytoplasts and have the potential to support development of full-term calves after transfer into synchronized recipients.