Effect of egg yolk-based extender and seminal plasma removal on sperm viability of cooled donkey semen


  • Carolina Natalia Alonso Universidad Nacional de Río Cuarto, Facultad de Agronomía y Veterinaria, Laboratorio de Producción Equina, Río Cuarto, Córdoba, Argentina https://orcid.org/0000-0001-9794-0821
  • Catalina Castañeira Universidad Nacional de Río Cuarto, Facultad de Agronomía y Veterinaria, Laboratorio de Producción Equina, Río Cuarto, Córdoba, Argentina
  • Ana Flores Bragulat Universidad Nacional de Río Cuarto, Facultad de Agronomía y Veterinaria, Laboratorio de Producción Equina, Río Cuarto, Córdoba, Argentina
  • Luis Losinno Universidad Nacional de Río Cuarto, Facultad de Agronomía y Veterinaria, Laboratorio de Producción Equina, Río Cuarto, Córdoba, Argentina




Donkey, Cooled semen, Semen preservation, Seminal plasma, Egg yolk extender


Developing effective cooled semen protocols is essential to increase pregnancy rates and reproductive efficiency in donkeys. This study aimed to evaluate the effect on sperm kinetic parameters and membrane integrity in cooled donkey semen diluted with defined milk proteins extender with 1% or 2% of egg yolk and the removal of seminal plasma. Twenty-four ejaculates from six jackasses were collected. Each ejaculate was divided into four aliquots that were diluted in extender with 1% (EY1) or 2% (EY2) egg yolk. One sample from each group was centrifuged, seminal plasma was removed (CEY1, CEY2 groups, respectively), and the samples were then refrigerated at 5 °C for 24 h. Fresh and cooled semen samples were assessed for sperm motility, morphology, and plasma membrane integrity. Total motility, progressive motility, sperm kinetic parameters, or live sperm cells were not statistically different when semen was cooled with an extender supplemented with 1% or 2% of egg yolk. Seminal plasma removal does not affect total motility or sperm kinetic parameters. However, progressive motility decreased (P<0.05) when semen was extended with 2% of egg yolk and seminal plasma was removed. Membrane integrity was affected (P<0.05) in centrifuged samples. In conclusion, the obtained results suggest that there is no difference in sperm kinetics and membrane integrity when 1% or 2% of egg yolk was added to the Equiplus(R) extender. Also, the removal of seminal plasma by centrifugation did not have any beneficial effect on cooled donkey semen. Further studies are needed to relate these results with in vivo fertility tests with cooled donkey semen.


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How to Cite

Alonso CN, Castañeira C, Bragulat AF, Losinno L. Effect of egg yolk-based extender and seminal plasma removal on sperm viability of cooled donkey semen. Braz. J. Vet. Res. Anim. Sci. [Internet]. 2021 Apr. 23 [cited 2024 May 23];58:e174301. Available from: https://www.revistas.usp.br/bjvras/article/view/174301