Effect of ovarian stimulation treatments on the embryo quality in rabbit

Our outcomes showed that both the ovulation rate and the mean of recovered transferable embryos per donor were similar among the different ovarian stimulation groups (FSH-CTP, FSH-CTP plus rhLH, rhFSH, rhFSH plus rhLH), but much higher than the control group. In vitro viability of superovulated embryos from FSH-CTP group was similar to the embryos from the control group until blastocysts stage at 48 hours, but it was higher at expanded blastocyst stage for FSH-CTP group in relation to the control group at 48 hours. The embryo development at any stage was affected by the vitrification process. However, it seems that ovarian stimulation did not affect the SOX2 and OCT4 gene expression. NANOG gene overexpression was observed in embryos from FSH-CTP, FSH-CTP plus rhLH and rhFSH in concordance with the higher in vitro embryo development of these groups. In vivo viability of embryos from both FSH-CTP and FSH-CTP plus rhLH experimental groups was similar to the embryos viability from the control group. The in vivo embryo viability at implantation stage was affected by the vitrification process, but foetal losses and birth rate was not affected. Nevertheless, it seems that the vitrification did not affect the in vivo viability of embryos from FSH-CTP and rhFSH groups in relation to the control group. There was no difference in the litter size and weight at birth and weaning among the experimental groups. The vitrification did not affect the litter size at birth and weaning but the pup weight who came from the vitrified embryos was five per cent higher than the one in the fresh groups. By contrast, weight at weaning was lower than the fresh group. In conclusion, the results of this study suggest that the use of FSH-CTP (3 μg per doe) is enough to superovulate rabbit does without compromising the quantity and quality of embryos, either fresh or vitrified. In addition, the use of this hormone reduces the frequency of animal handling, improving the animal welfare too.