The surgical oocyte retrieval and the developmental potential of the oocytes derived from prepubertal domestic species

• Main Authors: Sheng-Po Yeh, 葉盛伯
• Other Authors: Jyh-Cherng Ju, Ph. D.
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/98661585651036329049

碩士 === 國立中興大學 === 畜產學系 === 90 === The in vitro embryo production（IVP）system has been widely used in cattle embryos as well as that in other domestic species. Due to its long prepubertal and gestation periods, the efficiencies in genetic improvement and herd expansion have been compromised. The use of juvenile or prepubertal animal’s oocytes for IVP may be one of the solutions. The objectives of this study were to investigate the ovarian responsiveness of juvenile animals to exogenous gonadotropin treatments and to establish the oocyte retrieval technique for juvenile farm species. Three 75-day-old calves were treated with 4 doses of FSH (Folltropin V) at a 12-hour interval (40, 30, 30, and 30 mg, respectively) up to 7.5-month-old. Surgical oocyte retrieval was performed 24 h after the last FSH injection in each round of treatment. Calves with good responses to FSH treatment had an average ovarian size of 5x3 cm compared to 3x2 cm of the less-responsive animals. Total numbers of ovarian surface follicles and oocyte recovery ranged from 9 to 110 and 1 to 68, respectively. The average diameter of oocytes is 144 mm, which is slightly smaller than that from mature cows (149 mm). Oocyte maturation rates were various ranging from 0-42%. Similar trends were observed in the case of juvenile goats. In contrast, no ovarian responses were observed when 1-2 months of juvenile pigs were treated with FSH. In conclusion, juvenile/prepubertal calves and goats responded to gonadotropin treatments, which was not in the case of pigs in this experiment. Higher hormonal dosages or combinations may be required to induce the growth of ovarian follicles in all species examined. When the donor animals were selected critically, calf or goat oocytes may serve as an alternative source of germplasms for embryo production. Further studies are required to optimize the IVP system for the oocytes derived from juvenile animals.