Impact of in vitro fertilization by fresh and frozen semen on developmental competence and cryotolerance of buffalo embryos.

Production of high quality embryos in vitro needs an efficient in vitro fertilization (IVF). Seminal origin is one of the important factors that affects the success of in vitro embryo production. So our goal was to determine the effect of using fresh and frozen semen in fertilization on developmental competence and cryo-survival of buffalo embryos. Buffalo oocytes were matured and fertilized in vitro by fresh and frozen semen. After embryos evaluation, good quality morula and blastocysts were vitrified using 0.25 ml straws and the post-warmed viability was assessed by further culture for 24 h. There was no significant difference in cleavage rate between embryos derived from fresh and frozen semen, whereas the rate of embryo development to the morula (P<0.05) and blastocysts (P<0.01) stages was significantly decreased in embryos derived from frozen compared to fresh semen. After warming the vitrified embryos, there was no significant difference between embryos derived from fresh and frozen semen in the percentages of morphologically viable embryos. However, 24 h after culture, the rate of morphologically normal and survived embryos was increased (P<0.05) in embryos derived from fresh compared to the frozen semen. In conclusion, in buffalo, the use of fresh semen could improve the rate of embryo development and their crytolerance compared to the frozen semen.