EMBRYO PRODUCTION MODEL OF ENDANGERED SPECIES IN BOVIOIDEA BY IN VITRO FERTILIZATION USING SPERM INJECTION

作为遗传资源的非家养濒危物种的保护是动物科学的重要课题。微操作技术的最新进展和基础研究成果的积累将极大地促进这一课题的发展。这项研究的主要目的是通过显微注射死动物的精子来产生胚胎。死的动物属于牛科动物，由大阪市动物园提供。从冷冻解冻的睾丸或附睾处回收精子。这些材料的状况并不稳定。显微辅助受精卵母细胞的存活率取决于精子的注射方式。我们得到了一些正常的氙气受精卵母细胞的样本。这一结果证明该系统可用于胚胎生产，但仍处于较低水平，不能用于实际应用。此外，成熟卵母细胞的供应对胚胎的生产至关重要。根据我们的数据，从死动物中提取的精子不久将能够通过辅助受精使卵母细胞受精。然而，我们可以从死动物的卵巢中回收符合条件的卵母细胞进行体外受精。进一步的研究工作对于发育成熟的无减数分裂能力的未成熟卵母细胞是必要的。总而言之，这些技术在动物育种和濒危物种保护方面的发展潜力显然非常大。

Conservation of non-domestic endangered species as genetic resource is an important subject of animal science. Recent advances in the micro-manipulation techniques and accumulation of the fundamental research achievement will greatly contribute to this subject. Main purpose of this research is to produce embryos by microinjection of spermatozoa derived from dead animals. Dead animals belonged to bovioidea were offered by Osaka City Zoo. Spermatozoa were recovered from frozen-thawed testis or epididymis. Condition of these materials was not stable. Surviving rate of micro-assisted fertilization oocytes depended on the method of injection of spermatozoa. We got a few samples of normal xenon-fertilized oocytes. This esult proved to use this system for embryo production, however still too low to use it practically. Moreover, supply of matured oocytes for fertilization become critical for production of embryos. According to our data, sperm derived from dead animals will be able to fertilize oocytes by assisted fertilization soon. However, we can recover eligible oocytes for in vitro fertilization in the ovary derived from dead animals. Further research effort is necessary for development of maturing immature oocytes without meiotic competence. In conclusion, the potential for the development of these techniques for use in animal breeding and conservation of endangered species is clearly very great.