Pregnancy rate following transfer of in vitro produced lamb derived embryos in two embryonic stages.
Ovine embryos were produced by maturation, fertilization and in vitro culture (IVM/IVF/IVC) of oocytes collected from slaughtered prepubertal ewes. At 24 h post IVM, oocytes were fertilized with fresh semen collected from Lori-Bakhtiari breed at a concentration of 1.0 x l0(6) sperm mL(-1). The presumptive ova/embryos were transferred into the embryo culture medium at 22-24 h post IVF. Following 4 to 7 day in culture, embryos (at morula and blastocyst stage, respectively) were transferred surgically to the uterine horn of synchronized recipients. Pregnancy was diagnosed at day 30 by hormonal assay and at days 55 and 140 of gestation by ultrasonography and pregnancies were allowed to go to term. A total of nine ewes received 27 embryos (3 embryos/ewe). Five ewes received 15 embryos at morula stage and four ewes received 12 embryos at blastocyst stage. From those received morula stage embryos one was pregnant on day 30 (20%), though no pregnancy was diagnosed on each of days 55 and 140. While from those received blastocyst stage embryos, three ewes were pregnant on day 30 (75%) and two ewes (50%) remained pregnant on each of days 55 and 140. In conclusion, day 4 IVM-IVF morula stage embryos had a lower survival rate than did day 7 IVM-IVF blastocysts embryos, following transfer to the synchronized recipient ewes.
Shirazi
A
A
Research Institute of Animal Embryo Technology, Shahrekord University, P.O. Box 115, Shahrekord, Iran.
Shams-Esfandabadi
N
N
Ahmadi
E
E
Jadidi
M
M
Heidari
B
B
D000818:Animals; D001755:Blastocyst / Q000166:cytology; D046149:Embryo Culture Techniques; D004624:Embryo Transfer / Q000379:methods*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D009028:Morula / Q000166:cytology; D009865:Oocytes / Q000166:cytology; D011247:Pregnancy; D018873:Pregnancy Rate; D011270:Pregnancy, Animal; D012756:Sheep; D013997:Time Factors