Studies On Vitrification Of Rabbit Embryos With The Open Pulled Straw (OPS) Method

In this paper, 58 female rabbits of China were superovulated with FSH (made in China) and PMSG ( made in Germany) , and rabbit embryos were vitrified with two different concentration freezing media(VS I and V S II) with the OPS method. The results were as follows:1 Both FSH and PMSG had perfect superovulation effects on rabbits. The average number of ovulation point and the average number of embryos recoverd from FSH-treated rabbits were 28.5 ± 18.0 and 22.5 + 13.2, respectively; The average number of ovulation point and the average number of embryos recovered from PMSG-treated rabbits were 27.0±11.9 and 23.6 + 9.8, respectively. They showed no significant difference (P>0.05) . But in consideration of distributions of the numbers of embryos recovered from rabbits, the superovulation effect of PMSG was more stable than that of FSH .2 More embryos were recovered from the right ovary than the left one from FSH-treated rabbits (53.7% and 46.3%, respectively ), and so was the case in PMSG-treated rabbits (50.5% and 49.5%, respectively). FSH group showed significant difference (P<0.01) , but PMSG group showed no significant difference(P>0.05) .3 The superovulation effects of two gonadotropins in Spring were better than that in Autumn (P<0.01) .4 641 morulas were vitrified with the OPS method. After thawing, the overall embryos' recovery rate of was 93.8% (601/641), 568 of which (94.5%) were morphologically intact embryos, and all of 601 embryos' zona pellucid were intact (100%). The embryos' recovery rate of VS I and VSII were 93.8% (305/325) and 93.7% (296/316) , respectively. 290 (94.5%) and 278 (94.0%) were morphologically intact embryos for VS I and VS II, respectively. There was no difference in the embryos' recovery rate between VS I and VS II, and the rate of morphologically intact embryos for VS I was remarkably higher than that for VS II (P<0.05).5 After thawing, 415 morulas of excellent and good quality were transferred into 29 recipients. The overall pregnant rate was 51.7% (15/29) and the rate of embryos developing into young pups was 34.5%(61/177). The pregnant rate and the rate of embryos developing into young pups for VS I were 53.3% (8/15) and 36.8% (35/95) respectively. The correspondent values for VS II were 50.0% (7/14) and 31.7% (26/82). The values of VS I were higher than that of VS II, but the difference was. not significant (P>0.05).