Effects of β-mercaptoethanol Concentrations on Developmental Ability of Oocytes in 6-week-old Dorper Sheep

This study was conducted to investigate the effects of different concentrations ofβ-mercaptoethanol on the development ability of oocytes in Dorper sheep at the age of 6 weeks.In this study,6 Dorper sheep of 6 weeks old were chosen to induce oocyte collection in vivo by gonadotropin,and A and B grade cumulus oocyte complexes were obtained(COCs)with different concentrations of(0,50,70 and 100μmol/L)ofβ-mercaptoethanol in the mature liquid.The cleavage rate and blastocyst rate were counted after matured oocytes and capacitated sperm were co-incubated and fertilized eggs were cultivated.The results showed that compared with the cleavage rate(59.13%)and the blastocyst rate(12.17%)of the control group,the cleavage rates(60.87%,63.48%and 65.22%)and blastocyst rates(14.78%,17.39%and 21.74%)of the test groups I,II and III were higher(P>0.05),and the order was test group III>test group II>test group I>control group.The cleavage rate and blastocyst rate of the 100μmol/Lβ-mercaptoethanol group increased by 6.09 percentage points and 9.57 percentage points,respectively.It indicated that the addition of a certain amount ofβ-mercaptoethanol in the mature liquid could improve the developmental ability of oocytes and the quality of fertilized eggs of the 6-week-old Doper sheep.When theβ-mercaptoethanol concentration was within 100μmol/L,the cleavage rate and the blastocyst rate of oocytes were on the rise.The optimal concentration ofβ-mercaptoethanol in the mature liquid still needs further study.

Study on In-vitro Production Technology of Embryos from Young Dorper Sheep

This study was conducted to investigate the in-vitro production technology of embryos from young Dorper sheep, so as to provide technical support for the utilization of ovarian follicles in young Dorper sheep. Tests were conducted from the induction of Dorper sheep of 4 to 8 weeks old using follicle stimulating hormone(FSH) and pregnant horse serum(PMSG), collection of oocytes, in-vitro oocyte maturation-fertilization-zygote cultivation and 2-4-cell-stage fertilized ovum transfer. The results showed that 585 oocytes were collected from eight Dorper sheep at the age of 4 and 8 weeks, with an average of 73.13 oocytes/sheep. 346 of the 2-4-cell-stage fertilized eggs were obtained, whose cleavage rate was 59.15%. 77 in-vitro fertilized eggs at 2-4-cell stage were transplanted into 17 recipient sheep, seven of which were pregnant and gave birth to 13 "test-tube sheep" with a conception rate of 41.18%. It is indicated that the hormone induction technique, in-vitro oocyte maturation-fertilization-zygote cultivation technique and 2-4-cell-stage fertilized ovum transfer technique used in this study can serve as effective techniques for the in-vitro production of embryos from Dorper sheep of 4-8 weeks old.