Comparison of in vitro fertilization and nuclear transfer techniques in the production of buffalo pre-implantation embryos

Abstract

This study was conducted to evaluate the timing of cleavage and blastocoel formation of in vitro fertilized and nuclear transfer embryos and to compare the efficiency of in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT) techniques in the production of buffalo embryos under the same culture system. Cumulus oocyte complexes (COCs) were matured in vitro for 22 and 24 hr for SCNT and IVF, respectively. For IVF, COCs were inseminated with frozen-thawed semen and cultured in modified synthetic ovi-ductal fluid supplemented with amino acids for 7 days. For SCNT, ear skin fibroblasts were inserted individually into enucleated oocytes, fused electrically, and activated with ethanol followed by cycloheximide treatment for 6 hr before culture in the same condition as IVF embryos. The results showed that SCNT embryos cleaved and formed blastocoel earlier than IVF embryos. The cleavage rate is significantly higher in SCNT embryos; while the blastocyst formation rate of IVF embryos is significantly higher (P<0.01) than SCNT embryos. The shorter time taken from cleavage to blastocoel formation by NT embryos as compared to in vitro fertilized ones suggests a difference in their developmental kinetics. The difference in the developmental competence between NT and IVF embryos warrants further investigation.