title: Cryopreservation of epididymal stallion sperm.
abstract: Any event that makes semen collection or mating impossible, such as death, castration, or injury, may terminate a stallion's breeding career. Fortunately, stallion sperm which are capable of fertilization can be harvested from the epididymis, and frozen for future use. However, the fertility of frozen-thawed epididymal sperm has been found to be lower than that of ejaculated sperm. Therefore, this study aimed to optimize the fertility of frozen epididymal stallion sperm by investigating the effects of different cryoprotectants and freezing protocols on sperm quality. Dimethylformamide was tested alone or combination with pasteurized egg yolk as substitute of fresh egg yolk. In addition, the effect of the pre-freeze stabilization on sperm quality was analyzed. Heterospermic samples obtained from stallion epididymis were collected and cryopreserved in lactose-egg-yolk extender or in the same extender with varying content of cryoprotectant and content of egg yolk, stabilized and no-stabilized. Sperm motility, viability, hypoosmotic swelling test (HOST) and acrosome integrity were evaluated post-thawing. No improvement was observed on the replacement of fresh yolk by pasteurized egg yolk, whereas the results suggest that dimethylformamide is a cryoprotectant suitable for cryopreservation of equine epididymal semen, even better than glycerol. In addition, we found that the stabilization before freezing on epididymal stallion sperm, can improve sperm quality parameters.
authors.affiliation: Department of Animal Pathology, Obstetric and Reproduction Area, Faculty of Veterinary Medicine, Universidad de Zaragoza, Spain. Electronic address: maiteor88@gmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Olaciregui
authors.affiliation: Department of Animal Pathology, Obstetric and Reproduction Area, Faculty of Veterinary Medicine, Universidad de Zaragoza, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Gil
authors.affiliation: Department of Animal Pathology, Obstetric and Reproduction Area, Faculty of Veterinary Medicine, Universidad de Zaragoza, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Montón
authors.affiliation: Department of Animal Pathology, Obstetric and Reproduction Area, Faculty of Veterinary Medicine, Universidad de Zaragoza, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Luño
authors.affiliation: Department of Animal Pathology, Obstetric and Reproduction Area, Faculty of Veterinary Medicine, Universidad de Zaragoza, Spain.
authors.forename: R A
authors.initials: RA
authors.lastname: Jerez
authors.affiliation: Department of Animal Pathology, Obstetric and Reproduction Area, Faculty of Veterinary Medicine, Universidad de Zaragoza, Spain.
authors.forename: J I
authors.initials: JI
authors.lastname: Martí
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D015925:Cryopreservation; D003451:Cryoprotective Agents / Q000494:pharmacology*; D004126:Dimethylformamide / Q000494:pharmacology*; D004530:Egg Yolk / Q000737:chemistry; D004822:Epididymis / Q000166:cytology / Q000502:physiology; D005990:Glycerol / Q000494:pharmacology; D006736:Horses; D008297:Male; D009994:Osmolar Concentration; D012662:Semen Preservation / Q000379:methods*; D013081:Sperm Motility / Q000187:drug effects / Q000502:physiology; D013094:Spermatozoa / Q000187:drug effects* / Q000502:physiology
chemical_list: D003451:Cryoprotective Agents; D004126:Dimethylformamide; D005990:Glycerol
keywords: Cooling rate; Cryopreservation; Cryoprotectant; Egg yolk; Epididymal sperm; Stallion