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Research article - Peer-reviewed, 2021

Low density Porcicoll separates spermatozoa from bacteria and retains sperm quality

Martínez-Pastor, F.; Lacalle, E.; Martínez-Martínez, S.; Fernández-Alegre, E.; Álvarez-Fernández, L.; Martinez-Alborcia, M.-J.; Morrell, Jane


Antibiotics are added to semen extenders to control the growth of bacteria contaminating semen during collection but may contribute to the development of antibiotic resistance. An alternative would be physical separation of spermatozoa from bacteria. The objective of the present study was to evaluate two low densities of Porcicoll for removal of bacteria, and for their effect on sperm recovery and sperm quality. Semen was collected from boars at a commercial station. Aliquots of 8 extended ejaculates were subjected to colloid centrifugation through 20% Porcicoll (P20) and 30% Porcicoll (P30) in 500 mL tubes and then stored at 17 °C. Microbiological examination and sperm quality evaluation (computer assisted sperm analysis and flow cytometry) were carried out on controls and all colloid-selected samples immediately after preparation and again after storage for 3 and 7 days. The microorganisms found were mainly bacteria from the environment, gut or skin. There was a considerable reduction or complete removal of some bacteria by both colloids. Recovery rates were 86% for P20 and 81% for P30. Sperm quality was not adversely affected by colloid centrifugation on day 0, and thereafter showed a more gradual deterioration in colloid centrifuged samples than in controls, possibly due to lower bacterial contamination. There were no differences in sperm quality between the two colloid treatments. Thus, these results show that contaminating bacteria in semen can be controlled by centrifugation through low density colloids.


Bacteriospermia; Single layer centrifguation; Silane-coated silica colloids; Environmental contaminants; Boar semen

Published in

2021, volume: 165, pages: 28-36

Authors' information

Martínez-Pastor, F.
University of León
Lacalle, E.
University of León
Martínez-Martínez, S.
University of León
Fernández-Alegre, E.
University of León
Álvarez-Fernández, L.
University of León
Martinez-Alborcia, M.-J.
Topigs Norsvin
Bolarin, A.
Topigs Norsvin
Swedish University of Agricultural Sciences, Department of Clinical Sciences

UKÄ Subject classification

Clinical Science

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