Studies On The In Vitro Fertilization Of Buffalo Oocytes And Evaluation Of Embryo Quality

Effects of semen on the in vitro fertilization (IVF) of buffalo oocytes were examined, and the difference in quality of buffalo embryos derived from parthenogenetic activation (PA),nuclear transfer (NT) and IVF was also compared in this study.Effects of bulls and diluent components of frozen semen on the in vitro fertilization of buffalo oocytes were investigated. A significant variation was observed in either cleavage rate or blastocyst yield of oocytes fertilized using the semen from different bulls (n=4, P < 0. 05). Significant more oocytes cleaved and developed to blastocysts when semen frozen in the diluent consisting of fructose, Tris and egg yolk was employed for in vitro fertilization in comparison with the semen frozen in lactose, glucose and egg-yolk (51.9% vs. 20.0%, 35.0% vs. 5.0%; P<0.01). Addition of antioxidant (300IU/ml SOD and 1.0 mM GSH) to the semen frozen diluent significantly improved the in vitro fertilization efficiency of the semen, as evidenced with that more oocytes fertilized in this semen cleaved (62.7% vs 50.9%, P<0.05).The cell number and prorein expression pattern of buffalo embryos derived from PA, NT and IVF were investigated. No differences were found in the total cell number of embryos derived from PA, NT and IVF (PA=74.9±30.7, NT=78.5±25.5, IVF=73.5±28.8; P>0.05). However, the cell number of inner cell mass (ICM) of IVF embryos was significantly higher than that of PA and NT embryos (19.2±7.6 vs 15.8±5.4 and 15.9±6.6, P<0.05). The results of protein electrophoresis in SDS-PAGE showed that several novel protein appeared or up-regulated during the in vitro maturation of oocytes, while several protein disappeared or down-regulated at the end of maturation; the difference of protein expression pattern was not detected in the embryos derived from PA, NT and IVF until to 8-cell stage.