title: Effect of seminal plasma removal before cryopreservation of bovine semen obtained by electroejaculation on semen quality and in vitro fertility.
abstract: Cryopreservation of bull semen is a common biotechnology procedure in cattle breeding. However, when the ejaculate is obtained by electroejaculation, wide variation is observed in the sperm/seminal plasma (SP) ratio that can affect the freezability of semen in this species. The removal of SP may improve the quality of frozen bull semen. The objective of this study was to evaluate the effect of SP removal from the ejaculate on the cryopreservation of semen from 38 Nellore bulls collected by electroejaculation. After collection, the ejaculate was divided into three aliquots: (1) control (N) diluted to a concentration of 60 × 106spermatozoa/mL and frozen with SP; (2) centrifugation (C) at ×600g for 10 minutes and the pellet resuspended and frozen at the same concentration as N; and (3) filtration (F) through SpermFilter and sperm recovered and frozen at the same concentration as N. After thawing, sperm kinetics, plasma and acrosome membrane integrity, mitochondrial membrane potential, oxidative stress, and in vitro fertility were evaluated. Statistical analysis was performed using the SAS 9.2 package, and differences were considered significant when P < 0.05. Higher average path velocity and straight-line velocity were observed in the groups submitted to SP removal compared to the control group (P < 0.01). In contrast, filtered samples exhibited higher beat cross frequency, straightness, and linearity compared to the other groups. Plasma membrane integrity was reduced when SP was removed, but lower oxidative stress was observed in groups C and F (34.91 ± 2.95% and 31.63 ± 2.95%, respectively) compared to group N (57.39 ± 2.95%). However, the percentage of hatched blastocysts was similar in the N and F groups (21.22 ± 1.05% and 24.00 ± 1.05%, respectively) and higher compared to group C (18.83 ± 1.05%). In conclusion, removal of SP by centrifugation for bull semen freezing reduced the rate of in vitro-produced embryos, whereas filtration of prefrozen semen was found to be an efficient alternative in terms of semen freezability and in vitro production of bovine embryos.
authors.affiliation: Departamento de Reprodução Animal, Universidade Estadual Paulista, FCAV/UNESP, Jaboticabal, São Paulo, Brasil. Electronic address: supc@hotmail.com.
authors.forename: Suzane Peres
authors.initials: SP
authors.lastname: Campanholi
authors.affiliation: Centro APTA Bovinos de Corte, IZ-APTA, Sertãozinho, São Paulo, Brasil.
authors.forename: Fabio Morato
authors.initials: FM
authors.lastname: Monteiro
authors.affiliation: Centro APTA Bovinos de Corte, IZ-APTA, Sertãozinho, São Paulo, Brasil.
authors.forename: Erika Aline
authors.initials: EA
authors.lastname: Ribeiro Dias
authors.affiliation: Centro APTA Bovinos de Corte, IZ-APTA, Sertãozinho, São Paulo, Brasil.
authors.forename: Maria Eugênia Zerlotti
authors.initials: MEZ
authors.lastname: Mercadante
authors.affiliation: Centro APTA Bovinos de Corte, IZ-APTA, Sertãozinho, São Paulo, Brasil.
authors.forename: Claudia Cristina Paro
authors.initials: CCP
authors.lastname: de Paz
authors.affiliation: Departamento de Reprodução Animal e Radiologia Veterinária, Universidade Estadual Paulista, FMVZ/UNESP, Botucatu, São Paulo, Brasil.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Dell'Aqua Junior
authors.affiliation: Departamento de Reprodução Animal e Radiologia Veterinária, Universidade Estadual Paulista, FMVZ/UNESP, Botucatu, São Paulo, Brasil.
authors.forename: Frederico Ozanam
authors.initials: FO
authors.lastname: Papa
authors.affiliation: Departamento de Reprodução Animal e Radiologia Veterinária, Universidade Estadual Paulista, FMVZ/UNESP, Botucatu, São Paulo, Brasil.
authors.forename: Camila de Paula Freitas
authors.initials: CPF
authors.lastname: Dell'Aqua
authors.affiliation: Departamento de Reprodução Animal, Universidade Estadual Paulista, FCAV/UNESP, Jaboticabal, São Paulo, Brasil.
authors.forename: Roberta
authors.initials: R
authors.lastname: Vantini
authors.affiliation: Departamento de Reprodução Animal, Universidade Estadual Paulista, FCAV/UNESP, Jaboticabal, São Paulo, Brasil.
authors.forename: Joaquim Mansano
authors.initials: JM
authors.lastname: Garcia
mesh_terms: D000818:Animals; D002417:Cattle; D002498:Centrifugation; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D004542:Ejaculation; D004558:Electric Stimulation; D005298:Fertility; D005307:Fertilization in Vitro / Q000662:veterinary*; D005374:Filtration; D008297:Male; D012661:Semen; D055101:Semen Analysis; D012662:Semen Preservation / Q000379:methods*
keywords: Bull; Centrifugation; Cryopreservation; Filtration; Semen; Seminal plasma