| This dissertation taked the Yangtze River delta white goat as the research object. First of all, effects of different ages and dose of hormone were evaluated on lamb follicle development and ovarian histology; Secondly, goat ovaries were collected from the slaughterhouse, in order to study in-vitro meiotic progression and development competence of prepubertal goat oocytes compared with adult goat; And then, in vitro matured oocytes (IVM) and goat freezing sperms were fertilized in vitro, and effects of IVM time of prepubertal goat oocytes, the extent of cumulus during maturation and fertilization process on oocyte development capabilities were also investigated; Eventually, the relationship among oocyte diameter, meiotic and embryo developmental competence were analyzed; Furthermore, the systems ofⅣM,ⅣF of oocytes andⅣC of embryos in prepubertal goat were also optimized, which will further promote embryo biology development. The main results of this study were as follows:1. In the study, effects of age and dose of hormone were evaluated on lamb super ovulation. The results showed that the number of lamb usable follicles, COCs and unexpanded COCs of 45 days was significantly higher than that of 90 days(P＜0.05); After FSH 70IU administration, the number of usable follicles, COCs in lamb of 45 days was significantly higher than that of FSH 40IU administration (P＜0.05), but significantly lower than unexpanded COCs with FSH 40IU administration. After FSH 40IU administration, 23.33±1.53 oocytes were obtained from one side of the ovary in 45 days lamb, and the average number was significantly higher than all the other groups (P＜0.05). Histology of lamb ovaries with FSH treatment was studied. The results showed that effects of lamb with FSH treatment on diameter of primordial follicle and primary follicle were not significant, but significant on diameter of oocytes (P＜0.05); the difference of oocytes diameter was significant among all treatments, but they were normal oocytes. After FSH 40IU administration, the number of growing follicle was significantly higher than that of other groups (P＜0.05); With FSH 70IU administration, the number of follicle and nude oocytes was higher than that of FSH 40IU administration.2. The aim of this part was to compare the in-vitro meiotic progression and the development competence of prepubertal goat oocytes with adult goat oocytes. There was a significant difference in the meiotic pregression of oocytes from prepubertal goat and adult goat. During IVM 27 hours, resumption of meiosis in prepubertal goat oocytes ocurred within 7.21h, and oocytes reached MⅡstage at 23.96h after in vitro maturation. Adult goat oocytes resumpted meiosis quickly with germinal vesicle breakdown at 2.94h, and oocytes reached MⅡstage at 20.64h. From in vitro maturation 24 hours to 27 hours, the percent of adult goat oocytes reaching MⅡstage was significantly different, but not on prepubertal goat oocytes. The developmental competence of oocytes from adult goat was higher than oocytes from prepubertal goat after parthenogenetic activation.3. Rates of fertilization and cleaved in oocytes ofⅣM 21h were significantly lower than other time ofⅣM, and the rates of morulae/blastocysts in oocytes ofⅣM 24h and 27h were significantly higher than that ofⅣM 21h and 30h.4. Rates of fertilization and morulae/blastocysts in oocytes with fully expanded cumulus were significantly higher than those in oocytes with poorly expanded cumulus.5. Partial or complete removal of cumulus before fertilization had no effect on fertilization rates of oocytes, but complete removal of cumulus impaired embryo development, leading to reduced morulae/blastula rates.6. The diameter of oocytes was positively related to the percentage of oocytes at MⅡafterⅣM. At Oh ofⅣM, the percentages of oocytes arrested at GV differed statistically, being higher in the smallest oocytes. As the diameter increased, the percentage of oocytes at GVBD stage also increased significantly (P＜0.05). After 27h ofⅣM, the percentage of oocytes that reached MⅡwas significantly higher when the diameter of oocytes increased.7. The diameter of oocytes was positively related to rates of fertilization and morulae/ blastocysts. Total number of fertilization and morulae/blastocysts obtained after the culture period was statistically higher when oocyte diameter increased(P＜0.05). Statistical differences in the percentage of morulae/ blastocysts obtained were also observed in oocytes smaller than 135μm when compared to oocytes larger than 135μm(P＜0.05).8. TALP media was more suitable for the cleavage of prepubertai goat oocytes than BO media.9. SOFaa media was more suitable for the development of prepubertal goat embryos than CR1aa media.
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