title: Cryopreservation of semen in the dog: use of ultra-freezers of -152 degrees C as a viable alternative to liquid nitrogen.
abstract: This experimental work was carried out to validate the use of a -152 degrees C ultra-low temperature freezer to freeze and store canine semen. The semen of three dogs was pooled and processed to obtain a final dilution with a concentration of 100 x 10(6) spermatozoa/mL, glycerol at 5% and Equex at 0.5%. Then, four freezing protocols were tested to evaluate the cryosurvival of sperm at 1, 7, 30, 60 and 120 days after freezing: (I) semen was frozen and stored in liquid nitrogen; (II) semen was frozen in liquid nitrogen and stored in the ultra-low freezer at -152 degrees C; (III) semen was frozen in the vapour of liquid nitrogen and stored in the ultra-low freezer at -152 degrees C; (IV) semen was frozen and stored in the ultra-low freezer at -152 degrees C. Data were statistically analyzed by repeated measures analysis of variance to determine the effect of the freezing protocol and time on the sperm characteristics assessed. The percentages of sperm motility and of dead/live spermatozoa were similar throughout the experimental period, with no significant differences (P < 0.05) to be observed between four different freezing techniques tested. At 120 days after freezing, the percentage of abnormal cells and the percentage of sperm cells with abnormal acrosome were not significantly different between the freezing techniques. Although the number of dogs used was slightly low, in vitro results of this preliminary study showed that the use of ultra-freezers at -152 degrees C to freeze and store canine semen could be a viable alternative to liquid nitrogen.
authors.affiliation: Reproduction and Obstetrics, Faculty of Veterinary Science, University of Las Palmas de Gran Canaria, 35416 Arucas, Las Palmas, Spain.
authors.forename: Desirée
authors.initials: D
authors.lastname: Alamo
authors.forename: Miguel
authors.initials: M
authors.lastname: Batista
authors.forename: Fernando
authors.initials: F
authors.lastname: González
authors.forename: Noemí
authors.initials: N
authors.lastname: Rodríguez
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Cruz
authors.forename: Fernando
authors.initials: F
authors.lastname: Cabrera
authors.forename: Anselmo
authors.initials: A
authors.lastname: Gracia
mesh_terms: D000177:Acrosome / Q000648:ultrastructure; D000818:Animals; D002470:Cell Survival; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D004285:Dogs; D005990:Glycerol; D008297:Male; D009584:Nitrogen; D012661:Semen / Q000502:physiology*; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary*; D013076:Sperm Count; D013081:Sperm Motility; D013094:Spermatozoa / Q000002:abnormalities; D013696:Temperature; D013997:Time Factors
chemical_list: D009584:Nitrogen; D005990:Glycerol