| Co-Investigator(Kenkyū-buntansha) |
KOBAYASHI Naohiko Gifu Prefectural Beef cattle Res.Inst., Researcher, 研究員
FUJITANI Yasuhiro Osaka Prefectural Agri.and Foret.Res.Center, Researcher, 研究員
MINAMI Naojiro Kyoto Univ.Grad.School of Agri., Researcher, 農学研究科, 助手 (30212236)
HOSOI Yukihiko Kinki univ.Res.Inst.Bio.-Oriented Sci.and Tech., Assoc.Prof., 生物理工学部, 助教授 (70192739)
SUZUKI Tatsuyuki Yamaguchi Univ.School of Agriculture, Professor, 農学部, 教授 (00216409)
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| Research Abstract |
To develop the system for efficient production of live stock animals, especially cattle with superior genetic traits, attempts have been made to produce the embryos by in vitro culture system, including in vitro maturation and in vitro fertilization of oocytes collected from ovaries from live animals with transvaginal aspiration using ultrasound echo system with a linear probe. We first determined a suitable condition, especially aspiration pressure and needle diameter for bovine follicular oocyte collection with transvaginal aspiration. As a result, we found that when the aspiration condition of 18- gauge needle at 80 mmHg was used, the highest oocyte recovery rates were obtained. In the second experiments, to stimulate the development of small sized follicles in cow ovaries, we tried to remove dominant follicles in low responder cows to superovulatory stimulation with follicular aspiration using ultrasound-guided aspiration techniques. It was found that the aspiration of follicular f
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luids of dominant follicles greatly stimulates the development of small-sized follicles, and moreover that most of the small follicles developed result in the ovulation with superovulatory treatments. Thus, with follicular aspiration, recovery rates of embryos after superovulatory treatments followed by artificial insemination were highly improved in low responder cows. Furthermore, we found that injection of anti-inhibin antibody raised against procin inhibin peptide to such cows resulted in similar response to superovulatory treatments to the case of follicular aspiration. In the third experiments, we found that in vitro maturation of oocytes collected from small sized follicles of cow ovaries in medium containing fractions of bovine follicular fluids separated by heparin affinity chromatography promotes subsequent development to the blastocyst stage after in vitro fertilization. Furthermore, it was found that the promoting activities were exerted with midkine, a novel heparin binding growth /differentiation factor in bovine follicular fluids. Less
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