title: Effects of rapid cooling prior to freezing on the quality of canine cryopreserved spermatozoa.
abstract: The aim of this study was to evaluate the effects of rapid cooling prior to freezing on frozen-thawed canine sperm quality. In experiment 1, centrifuged ejaculates from 6 dogs were pooled, split into 4 aliquots and cryopreserved by the Uppsala procedure using different cooling rates (control, cooling speed 18 C/90 min and average cooling rate 0.2 C/min; rapid, cooling speed 18 C/8 min and average cooling rate 2.25 C/min) in combination with 2 glycerol addition protocols (fractionated or unfractionated). In experiment 2, centrifuged ejaculates from 4 dogs were processed individually using the same cooling rates described in experiment 1 in combination with an unfractionated glycerol addition protocol. Each of the experiments was replicated 5 times. Sperm quality was evaluated after 30 and 150 min of post-thawing incubation at 38 C. Total motility (TM), progressive motility (PM) and quality of movement parameters were assessed using a computerized system, and sperm viability (spermatozoa with intact plasma and acrosome membranes) was assessed using flow cytometry (H-42/PI/FITC-PNA). Values for TM, PM, viable spermatozoa and the quality of movement parameters after thawing were not significantly affected by the cooling rate. The interaction between the cooling rate and the added glycerol protocol was not significant. There were significant differences among the males (P<0.01) in the sperm quality parameters evaluated after thawing. The interaction between the males and the cooling rate was not significant. In conclusion, canine spermatozoa can be cryopreserved using the Uppsala method at an average cooling rate of 2.25 C/min prior to freezing together with addition of fractionated or unfractionated glycerol.
authors.affiliation: Department of Animal Medicine and Surgery, University of Murcia, Espinardo 30100, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Rodenas
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Parrilla
authors.forename: Jordi
authors.initials: J
authors.lastname: Roca
authors.forename: Emilio Arsenio
authors.initials: EA
authors.lastname: Martinez
authors.forename: Xiomara
authors.initials: X
authors.lastname: Lucas
mesh_terms: D000818:Animals; D002470:Cell Survival; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D003451:Cryoprotective Agents; D004285:Dogs; D005990:Glycerol; D006358:Hot Temperature; D007700:Kinetics; D008297:Male; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary*; D013081:Sperm Motility; D013094:Spermatozoa / Q000502:physiology*
chemical_list: D003451:Cryoprotective Agents; D005990:Glycerol