title: Substitution of egg yolk by a cyclodextrin-cholesterol complex allows a reduction of the glycerol concentration into the freezing medium of equine sperm.
abstract: The aim of this work was to completely replace the egg yolk a classical diluent for freezing equine semen by a cyclodextrin-cholesterol complex. At the same time, the reduction in the glycerol content used for cryopreservation and the incubation time between sperm and the freezing media were evaluated. Horse ejaculates were frozen with four different freezing extenders: a frozen reference medium (IF) containing egg yolk and 2.5% glycerol and media without egg yolk but supplemented with 1.5 mg 2-hydroxypropyl-beta-cyclodextrin cholesterol (HPβCD-C) complex and containing either 1% (G1), 2% (G2) or 3% glycerol (G3). Three incubation times (90, 120 and 180 min) at 4 °C between the fresh semen and the different media were tested before freezing. Viability and motility analyses were performed with computer assisted semen analysis (CASA). Results showed that the freezing media containing the HPβCD-C complex with 1%, 2% and 3% glycerol significantly improve the 3 in vitro parameters of post thawing semen quality (viability, progressive and total mobilities) compared to IF. The best improvement of the parameters was obtained with G1 medium and the longest contact time. The substitution of egg yolk by HPβCD-C complex allows the decrease of protein charge of the medium while favouring the cholesterol supply to membrane spermatozoa offering it a better resistance to osmotic imbalance and a better tolerance to the glycerol toxicity. Our results highlight that the egg yolk of an extender for the freezing of horse semen can be completely substituted by HPβCD-C complex.
authors.affiliation: LINALUX-MLS, Centre Européen du Cheval, Vielsalm, Belgium. Electronic address: didierblommaert@hotmail.com.
authors.forename: Didier
authors.initials: D
authors.lastname: Blommaert
authors.affiliation: Center for Oxygen Research and Development (CORD), University of Liège, Liège, Belgium.
authors.forename: Thierry
authors.initials: T
authors.lastname: Franck
authors.affiliation: Institut des Sciences de la Vie, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Donnay
authors.affiliation: LINALUX-MLS, Centre Européen du Cheval, Vielsalm, Belgium.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Lejeune
authors.affiliation: Department of Quantitative Genetics, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium.
authors.forename: Johann
authors.initials: J
authors.lastname: Detilleux
authors.affiliation: LINALUX-MLS, Centre Européen du Cheval, Vielsalm, Belgium; Center for Oxygen Research and Development (CORD), University of Liège, Liège, Belgium; Equine Clinic, Veterinary Medicine Faculty, University of Liège, Liège, Belgium.
authors.forename: Didier
authors.initials: D
authors.lastname: Serteyn
mesh_terms: D000073738:2-Hydroxypropyl-beta-cyclodextrin; D000818:Animals; D002784:Cholesterol / Q000378:metabolism*; D015925:Cryopreservation / Q000379:methods; D003451:Cryoprotective Agents / Q000378:metabolism*; D004530:Egg Yolk / Q000378:metabolism*; D005615:Freezing; D005990:Glycerol / Q000378:metabolism*; D006736:Horses; D006801:Humans; D008297:Male; D012661:Semen / Q000378:metabolism; D055101:Semen Analysis / Q000662:veterinary*; D012662:Semen Preservation / Q000379:methods* / Q000662:veterinary; D013081:Sperm Motility; D013094:Spermatozoa / Q000378:metabolism; D047392:beta-Cyclodextrins / Q000378:metabolism*
chemical_list: D003451:Cryoprotective Agents; D047392:beta-Cyclodextrins; D000073738:2-Hydroxypropyl-beta-cyclodextrin; D002784:Cholesterol; D005990:Glycerol
keywords: Cholesterol; Cryopreservation; Cyclodextrin; Spermatozoa; Stallion