Cryopreservation of epididymal and electroejaculated bull semen using liposome- and egg yolkbased extenders

Abstract

Objective of this study was to compare cryosurvival of epididymal (EP) and electroejaculated
(EE) sperm cryopreserved in liposome- or egg yolk- based extenders. Aliquots of EE sperm (n = 10
bulls) were cryopreserved with a liposome- (Optixcell; EEO) or egg yolk-based extender (Botubov;
EEB). Bulls were castrated and sperm from each cauda epididymis were cryopreserved with Optixcell
(EPO) or Botubov (EPB). Postthaw total motility was higher in semen frozen in Botubov than
Optixcell (p = 0.029). In addition, sperm distance and velocity parameters, and lateral head
displacement were higher in semen frozen in Optixcell (p = 0.01). Plasma and acrosomal membrane
integrity were higher with Botubov (EEB 60 ± 3%, EPB 59.7 ± 4%; mean ± SEM) than Optixcell
(EEO 37.8 ± 6%, EPO 25.8 ± 6%) (p < 0.0001). Capacitated cell percentage was lower with Botubov
(EEB 2 ± 0.4%, EPB 0.9 ± 0.3%) than Optixcell (EEO 6.9 ± 2.4%, EPO 4.2 ± 1.4%) (p < 0.0001).
Fewer EP sperm had high mitochondrial potential (EPB 6.6 ± 4.4%, EPO 14.6 ± 6.2%) than EE sperm
(EEB 46.7 ± 9.8%, EEO 41 ± 14.6%) (p = 0.0003), with no difference between extenders.