Farokh Kafilzadeh - Department of Animal Sciences,Faculty of Agriculture, Razi University, Kermanshah, Iran
Hamed Karami Shabankareh - Department of Animal Sciences,Faculty of Agriculture, Razi University, Kermanshah, Iran
Leila Soltani - Department of Animal Sciences,Faculty of Agriculture, Razi University, Kermanshah, Iran

Background: Improvements in culture media formulations have led to an increase in the ability of sheep embryo in culture throughout the preimplantation period.Objective: This study was carried out to evaluate the effects of various concentrations of MEM vitamins during in vitro maturation of sheep oocytes andsubsequent embryo development. Materials and Methods: Sheep ovaries were collected from a slaughterhouse andtransported to the laboratory. Oocytes were matured in SOF medium supplemented with, eCG, hCG and EGF in various concentrations of MEM vitamins (control, 0.5, 1 and 1.5 ) for 24h. The cumulus oocyte compelex (COCs) were co-incubated with epididymal spermatozoa of post mortem rams in synthetic oviduct fluid fertilization(SOFF) medium with 10% heat inactivated estrous sheep serum for 18h. Embryos were cultured in synthetic oviduct fluid culture 1 (SOFC1) medium for 48h followedby cultured in synthetic oviduct fluid culture 2 (SOFC2) medium for six days. Results: Addition of 0.5 and 1  MEM vitamins significantly increased (P< 0.05) overall blastocyst development (21.62% and 22.33%; respectively) compared with 1.5MEM vitamins (15.59%), but there was no difference between control, 0.5 and 1MEM vitamins in the percentage of embryos successfully developing to theblastocyst stage (19.50%, 21.62% and 22.33% respectively). Conclusion: It seems that addition of 1.5  of MEM vitamins has detrimental effect on blastocyst rate.

Embryo development, IVM, MEM vitamins, Sheep, SOF