Season Of Bovine Oocytes In Vitro Maturation And Somatic Cell Cloned Embryo Deyelopment Ability

In the process of bovine somatic cell nuclear transfer, the need for adequate mature oocytes as the basic material, while the use of slaughtered cattle ovaries from the slaughterhouse have a relatively abundant in oocytes. Slaughter cattle from different sources, are more affected by various factors, and Wuhan in the summer heat for a long time on the reproductive function of cattle has a great influence on the acquisition of bovine oocytes in vitro maturation and in vitro embryo development may be also affected. This study analyzed bovine oocytes number changes following recovery under different seasons in the rate of in vitro maturation and production of parthenogenetic embryos, somatic cell nuclear transfer embryos in vitro development changes. Identification of in vitro embryo quality not only in theory, help to in-depth study mechanism of embryonic development, can also better in the clinical guidance of the application of embryo transfer, so in theory and clinical have important significance.This study based on the methods reported, situation in our laboratory and previous workers’ experience, initially established staining methods to distinguish the quality in vitro embryos, in order to further improve the embryo quality and laid a foundation. The main results are as follows:1. Season on bovine oocyte maturation and in vitro embryo development potential.In this experiment, oocytes obtained from the cattle slaughterhouse by aspirared, cultured in maturation medium in 22-24h, and then mature oocytes divided into two parts, on part directly parthenogenetic activation cultured in vitro, and the other part for nuclear transfer, activation and embryo culture in vitro. Through experiments in the four seasons, the contrast between, we found:the spring of oocytes recovered in the cell number, oocyte maturation rate in vitro development of parthenogenetic embryos and in vitro development of somatic cells cloned embryos and other indicators were highst,had significant difference with other groups. Therefore, spring is the best season for most experiment, and it is suitable for production of bovine SCNT embryos.2. SCNT embryo transfer of preliminary results In this experiment, the first of cattle in cattle estrus synchronization treatment, then 6-8 days of laboratory culture to the morula or blastocyst development of SCNT embryo were transferred to estrus synchronized cows 6-8 days in estrus cyde in vivo.Until now, bovine SCNT embryo transfer efficiency has been low,30d rate not return to estrus in this experiment was 36.36%,60d rate not return to esfrus was 18.18%.