| Superovulation and Embryo Transfer(MOET)is the key technology for rapidly expanding the elite livestock flock.However,in ovine MOET practices,the superovulation performances varied among individuals and the overall outcomes were always unstable.DairyMeade is a new dairy sheep breed from New Zealand,which is an ideal male parent for the breeding of a local dairy sheep breed,while its superovulation performance was barely studied.AMH(Anti-Müllerian hormone)is mainly expressed in small antral follicles of ovary in mammals,whose concentration could be used as an important indicator of the ovarian reservation.In this study,the AMH concentrations of follicles classified by different diameters were firstly measured,and then the changes of AMH concentrations in DairyMeade peripheral blood during the whole estrus cycle were observed.After that,the superovulation performances of DairyMeade donors were compared by using different estrus synchronization methods(CIDR(10 d),CIDR(13 d)and natural estrus(13 d))and artificial insemination methods(cervical and laparoscope).Finally,the correlation between peripheral blood AMH concentrations before external FSH administration and the superovulation outcomes were studied.The results were as follows.1)TheAMH concentration within the follicles with diameter of 1-3 mm was extremely significant higher than those with diameter of 3-5 mm,5-8 mm and > 8 mm.The peripheral blood AMH concentrations fluctuated during a whole estrus cycle,which showed a “decrease – increase and reach the peak – decrease – increase” pattern;2)There was no significant differences in the average total number of embryos obtained by CIDR(10 d),CIDR(13 d)and natural estrus(13 d)after superovulation(16.5 vs12.2 vs 14.5,P > 0.05),but the average numbers of usable embryos in CIDR(10 d)and natural estrus(13 d)were significant higher than that of CIDR(13 d)(13.2,11.6vs 4.8,P < 0.05).3)When the CIDR(10 d)method was used,the peripheral blood AMH concentrations before the first external FSH treatment were positively correlated with the total recovered embryo numbers(r≥0.942,P < 0.05)and the usable embryo numbers(r ≥ 0.835,P < 0.05).These results indicated that,the content of AMH in peripheral blood of DariyMeade sheep fluctuated significantly during the estrous cycle,and the concentration of AMH in peripheral blood was positively correlated with the total number of recovered embryos and the number of available embryos,the peripheral blood AMH concentration could be used as an index to predict the superovulation performance of DariyMeade sheep. |
