Development of a method for prediction of bull semen fertility focusing on the structures of sperm motility subpopulation

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K14987
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 42020:Veterinary medical science-related
• Research Institution: Kitasato University
• Principal Investigator: Kanno Chihiro 北里大学, 獣医学部, 助教 (20834469)
• Project Period (FY): 2021-04-01 – 2023-03-31
• Keywords: 精子 / 牛 / 人工授精 / 妊孕性 / 運動性サブポピュレーション

Outline of Final Research Achievements

In this study, we analyzed the relationship between bovine sperm quality, including sperm motility subpopulation, and semen fertility to clarify the characteristics of highly fertile sperm.As a result, sperm in semen with high conception rate in artificial insemination (AI) showed linearly moving with high beat-cross frequency, maintain high mitochondrial activity even after thawing of frozen semen. This suggests sperm with linear movement have a long life span and high fertility. On the other hand, sperm in semen with a low conception rate in AI moved curvilinearly with large amplitude of head. These sperm could not maintain cell membrane addition integrity after a long time after thawing of semen. The results of this study show some of the factors that make it possible to predict the fertility of semen from cattle without AI tests in the field.

Free Research Field

繁殖学

Academic Significance and Societal Importance of the Research Achievements

これまで、精子の実験室的検査は広く行われてきた一方、その妊孕性を高精度に予測可能な手法は無かった。本研究の成果から、牛における高妊孕性精子の特徴の一端を解明することができた。今後、学術的には精子の運動様式の差異を生み出す機構の解明、社会的には人工授精所における精液検査の手法や新規凍結精液作製による、精液の品質管理および向上に、それぞれ繋がっていく知見であると考えられる。