Further approaches on sperm cryopreservation protocol towards the establishment of the sperm bank from endangered native Catalan ram breeds (Xisqueta and Aranesa)
- Autores: Uchebuchi Ike Osuagwuh
- Directores de la Tesis: María Jesús Palomo Peiró (dir. tes.)
- Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2017
- Idioma: español
- Tribunal Calificador de la Tesis: Marc Yeste Oliveras (presid.), María Montserrat Rivera del Álamo (secret.), Rosaura Pérez Pe (voc.)
- Programa de doctorado: Programa de Doctorado en Medicina y Sanidad Animales por la Universidad Autónoma de Barcelona
- Materias:
- Enlaces
- Resumen
The new interest towards the characterization and conservation of Aranesa and Xisqueta ram breeds was constituted by ex situ programs using assisted reproductive techniques such as semen cryopreservation and the development of sperm banks. This is in view towards preserving their genetic resouces following its ultimate use for artificial insemination. However, there are still concerns due to issues regarding frozen-thawed sperm quality. Therefore, with the present technological advances made in recent years on sperm evaluating techniques such as the use of computer-assisted sperm analysis and flow cytometry, a wealth of information on their sperm characteristics may be achieved. Furthermore, as the application of refrigerated and frozen-thawed semen technology increases, more information on sperm quality and advances are required.
In this doctoral thesis, the general aim was to provide some more information on Aranesa and Xisqueta sperm processes for cryopreservation as well as exploring some strategies towards improving their post-thawed sperm quality prior to testing for further application. To this regard, we evaluated the seasonal effect and melatonin implantation on their reproductive characteristics. In addition, the quality of sperm stored at 50C for 24h in a cryopreservation media from the various ram donors during a non-breeding and breeding season was determined. The goal was to provide some useful information on the effect of chilled liquid storage on sperm quality held for a period of time prior to cryopreservation or as an alternative to frozen-thawed semen for AI. This study demonstrated that melatonin implantation to rams during the non-breeding season improved almost all qualitative sperm parameters studied during chilled liquid semen storage.
Furthermore, in this thesis, the efficacy of two collection methods electroejaculation (EE) vs. artificial vagina (AV)) on fresh and post-thawed sperm quality of Aranesa ram sperm towards the establishment of a sperm bank. The objective being that for rapid constitution of the sperm bank especially from a large number of untrained males within a short period of time, information on semen recovery methods on pre- and post-thawed sperm quality is essential. Our finding supports the inclusion of EE method as a viable alternative and quicker method for semen collection towards the ongoing conservation program and establishment of Aranesa sperm cryobank.
Another study in this thesis evaluated the sperm motility and qualitative characteristics of ram spermatozoa cryopreserved with or without seminal plasma under a controlled condition and subjected to a 4 h post-thawing thermal evaluation test. The goal being that exposing these frozen-thawed sperm to thermal resistance test will provide some knowledge on their survivability in the female genital tract towards fertilizing the ovum. This study demonstrated that the presence of seminal plasma prior to cryopreservation was beneficial in maintaining post thawed sperm motility, and as such, may be useful for ex situ ram sperm cryopreservation towards its use for artificial insemination.
The last study in this thesis evaluated the effect of washing frozen-thawed sperm by centrifugation and subsequently supplementing with whole seminal plasma (20%) collected by EE from a non-breeding and breeding season or by AV from a breeding season, following a 90 min incubation period. The aim being that supplementing these sperm samples with different seminal plasma source following a thermal resistance test at 37oC will provide some insight as regards their quality and survivability in the female genital tract. This study demonstrates that supplementing frozen-thawed sperm with seminal plasma irrespective of its source maintained sperm functions and motility characteristics during a post-thawing incubation period. Furthermore, washing by centrifugation or removal of freezing component after thawing was not necessary.
We can therefore conclude from the results obtained in this thesis that melatonin implants on male during a non-breeding season provided a beneficial effect on ram sperm during chilled liquid storage, the inclusion of EE as method for semen collection towards the establishment of a sperm bank is recommendable, and finally, the presence of seminal plasma prior to cryopreservation or its addition to post-thawed sperm was important in maintaining sperm motility and functions.
