Effects Of Zinc Supplementation On Meiosis Maturation And Development Of Yak Oocytes

To gain the matured oocytes by in vitro maturation(IVM)is the key sector of modern breeding,whose quality has a significant influence on the oocytes’ ability of successful fertilization and early embryonic development.Compared with cow,when cultured in vitro,the yak’s oocytes have a lower blastocyst level and the oocytes oxidative damage and other reasons may reduce the fertilization rate of yak.Therefore,how to improve the quality of yak’s oocytes in vitro maturation is one of the key issues urgently to be resolved.Zinc is an indispensable trace elements in animal body to be significant role in promoting growth,proliferation and differentiation and regulation of immune.So far,zinc to the influence of yak’s oocytes in vitro maturation has been reported.In addition,the study found that survival in the Qinghai-Tibet Plateau yak lack of zinc in blood seasonally.The aim of this study was to investigate the effect of zinc sulfate on the maturation and development of yak oocytes in vitro.The results are as follows:1.The concentration of zinc in 40 yak blood and follicular fluid were 1.03 ± 0.01μg/m L and 0.20 ± 0.03μg/m L and without in IVM and IVF medium.2.The additional zinc sulfate had no significant effect on the proliferation of yak’s oocytes cumulus cells and the maturation rate of oocytes with 0,0.5,1.0,1.5 and 2.0 μg / m L(P>0.05).3.The addition of zinc(1.5 and 2.0 μg/m L)in IVM medium,the content of GSH in the mature yak oocytes was significantly higher than in the control group and low concentration groups(P<0.05).Compared with the control group,the content of ROS in yak oocytes was significantly decrease of zinc concentration(1.0,1.5,2.0 μg/m L),and the difference was significant(P<0.01).In addition,the addition of 2.0 μg / m L Zn significantly increased the content of SOD in yak oocytes complex(P<0.05).4.The results showed that the zinc group was significant higher than the control group with 0.5,1.0,1.5 and 2.0 μg/m L(72.67%、75.31%、81.17%和 80.07% VS 60.74%)(P<0.05).The addition of 2.0 μg/m L zinc sulfate significantly increased the blastocyst rate.5.The expression of zinc transporter gene in yak oocytes was detected by q RT-PCR.The results showed that The expression of Zn T(SLC30A3,SLC306,SLC30A9)and ZIP(SLC39A6,SLC39A14)family members in yak mature oocytes in with different zinc concentrations were expressed by q RT-RCR,and all with the increase of zinc concentration showed an upward trend with different rate each other,and the expression of performance were reduced on blastocyst stage.In summary,the addition of zinc in the in vitro culture system can improved the development of yak oocytes and embryos by regulating the expression of GSH,ROS and SOD levels and related transport genes.So the amount of zinc is good for the production effciency of yak’s oocytes and embryos in vitro culture in medium.