Consequences for the Bovine Embryo of Being Derived from a Spermatozoan Subjected to Post-Ejaculatory Aging and Heat Shock: Development to the Blastocyst Stage and Sex Ratio
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概要
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The objective was to determine whether aging of sperm caused by incubation at normothermic (38.5 C) or heat shock (40 C) temperatures for 4 h prior to oocyte insemination affects sperm motility, fertilizing ability, competence of the resultant embryo to develop to the blastocyst stage and blastocyst sex ratio. In the first experiment, the percent of sperm that were motile was reduced by aging (P<0.001) and the reduction in motility was greater for sperm at 40 C compared to sperm at 38.5 C (P<0.01). In the second experiment, oocytes were inseminated with aged sperm. A smaller percent of oocytes fertilized with sperm aged at either temperature cleaved by Day 3 after insemination than oocytes fertilized with fresh sperm (P<0.05). There was no effect of sperm aging on the percent of oocytes or cleaved embryos that developed to the blastocyst stage. Aging of sperm before fertilization at 38.5 C reduced the percent of blastocysts that were male (P=0.08). In the third experiment, incubation of sperm at 38.5 C or 40 C for 4 h did not reduce fertilizing ability of sperm as determined by pronuclear formation of oocytes at 18 h post insemination. In conclusion, aging of sperm reduced cleavage rate and the percent of blastocysts that were males but had no effect on the developmental capacity of the embryo. The effect of aging on cleavage rate may represent reduced motility and errors occurring after fertilization and pronuclear formation. Aging at a temperature characteristic of maternal hyperthermia had little additional effect except that polyspermy was reduced. Results indicate that embryo competence for development to the blastocyst stage is independent of sperm damage as a result of aging for 4 h at normothermic or hyperthermic temperatures.
論文 | ランダム
- 自然科学教育を問い直す--生物教育の立場から (子どもの発達と自然)
- 映像と印刷の特性を考える(映像と印刷教材の組み合わせに関する比較研究-心理学の場合-,映像表現の多様性-シンポジウムの記録-)
- 混和剤のかがく (こんくりいと・グルメ集--混和材料ア・ラ・カルト)
- 凝結遅延コンクリート(実用コンクリート技術講座-19-)
- セメントコンクリート用混和剤 選定のための試験方法