Studies on the composition variation and function of seminal plasma

Abstract

The application of seminal plasma in vitro and its role in vivo during cervical transit has long been questioned due to the contradictory results published throughout the literature. This thesis examines the complex nature of ram seminal plasma, providing a link between seminal plasma composition and sperm function during cryopreservation and transit following deposition in the female tract. The results reported herein clearly show that exposure to seminal plasma is fundamentally important for the successful transit of ram spermatozoa through the cervix and its variable proteomic composition is responsible for its contradictory effect on sperm function, which is reported throughout literature. Additionally, its cryoprotective effect varies depending on the presence and concentration of individual proteins.. It has begun the arduous task of screening seminal plasma proteins for their effect on sperm function, but further research is necessary to unequivocally identify and confirm these markers within this biological fluid. Nonetheless, these findings lay the groundwork for the future supplementation of spermatozoa with seminal plasma proteins. These proteins could ameliorate the apparent alterations which occur to the sperm membrane during cryopreservation, which may prevent the cervical transit of frozen-thawed ram spermatozoa. Success in this endeavour would facilitate cervical artificial insemination of ewes with frozen-thawed semen and allow the Australian sheep industry to finally realise the rapid genetic progress capable from the widespread use of elite sires.