title: Effects of extender and equilibration time on post-thaw motility and membrane integrity of cryopreserved Gyr bull semen evaluated by CASA and flow cytometry.
abstract: The objectives of the present study were to investigate the effects of three equilibration times (0, 2, and 4h) and two extenders (TRIS or Bioxcell) for cryopreservation of bull semen. Semen from 12 Gyr bulls was cryopreserved using an automated freezing machine. There were significant interactions between equilibration times and extenders for sperm motility and membrane integrity. The control treatment (0h equilibration) had the lowest values (P<0.05) for total (MOT) and progressive motilities (PROG), and percentage of sperm with intact plasma and acrosomal membranes (IPIA), with no significant differences between extenders. Extender TRIS had greater cryoprotective action than Bioxcell, with greater MOT, PROG, IPIA at 2 and 4h, as well as the lowest proportion of damaged plasma membrane (DPM, 72.2% vs. 85.8%) for all times. Equilibration for 4h yielded the most desirable (P<0.05) for MOT, PROG, and IPIA, and the least DPM percentage (86.5, 78.0, and 72.6% for 0, 2, and 4h, respectively). Overall, the combination of TRIS and 4h of equilibration was the most desirable semen cryopreservation method, with greatest MOT, PROG, and IPIA (TRIS-T4=26.8%; BIO-T4=18.3%) and the least DPM. In conclusion, based on objective analyses, equilibration during cryopreservation was essential for maintaining motility and integrity of sperm membranes; equilibration for 4h yielded the greatest sperm survival, independent of the extender used.
authors.affiliation: Department of Clinics and Surgery, School of Veterinary Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil.
authors.forename: Ticiano Guimarães
authors.initials: TG
authors.lastname: Leite
authors.forename: Vicente Ribeiro
authors.initials: VR
authors.lastname: do Vale Filho
authors.forename: Rubens Paes
authors.initials: RP
authors.lastname: de Arruda
authors.forename: André Furugen Cesar
authors.initials: AF
authors.lastname: de Andrade
authors.forename: Lucas Luz
authors.initials: LL
authors.lastname: Emerick
authors.forename: Fabiane Gilli
authors.initials: FG
authors.lastname: Zaffalon
authors.forename: Jorge André Matias
authors.initials: JA
authors.lastname: Martins
authors.forename: Venício José
authors.initials: VJ
authors.lastname: de Andrade
mesh_terms: D000818:Animals; D002138:Calibration; D002417:Cattle; D002463:Cell Membrane Permeability / Q000187:drug effects*; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary; D003451:Cryoprotective Agents / Q000494:pharmacology*; D005434:Flow Cytometry; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D012661:Semen / Q000166:cytology / Q000187:drug effects; D055101:Semen Analysis / Q000295:instrumentation / Q000379:methods; D012662:Semen Preservation / Q000009:adverse effects* / Q000379:methods / Q000662:veterinary; D013081:Sperm Motility / Q000187:drug effects* / Q000502:physiology; D013696:Temperature; D013997:Time Factors
chemical_list: D003451:Cryoprotective Agents