title: Sperm viability in the black-footed ferret (Mustela nigripes) is influenced by seminal and medium osmolality.
abstract: Fundamental knowledge of spermatozoa cryobiology can assist with optimizing cryopreservation protocols needed for genetic management of the endangered black-footed ferret. Objectives were to characterize semen osmolality and assess the influence of two media at various osmolalities on sperm viability. We examined the influence of Ham's F10 +Hepes medium (H) at 270, 400, 500 or 700 mOsm (adjusted with sucrose, a nonpermeating cryoprotectant) and TEST Yolk Buffer (TYB) with 0% (300 mOsm) versus 4% (900 mOsm) glycerol (a permeating cryoprotectant). Electroejaculates (n=16) were assessed for osmolality using a vapor pressure osmometer. For media comparison, semen (n=5) was collected in TYB 0%, split into six aliquots, and diluted in H270, H400, H500, H700, and TYB 0% or TYB 4%. Each sample was centrifuged (300 g, 8 min), resuspended in respective medium, and maintained at 37 degrees C for 3h. Sperm motility and forward progression were monitored every 30 min for 3h post-washing. Acrosomal integrity was monitored at 0 and 60 min post-washing. Results demonstrated that black-footed ferret semen has a comparatively high osmolality (mean+/-SEM, 513.1+/-32.6 mOsm; range, 366-791 mOsm). Ferret spermatozoa were sensitive to hyperosmotic stress. Specifically, sperm motility was more susceptible (P<0.01) to hyperosmotic conditions than acrosomal integrity, and neither were influenced (P>0.05) by hypotonic solutions. Exposure to TYB 4% glycerol retained more (P<0.01) sperm motility than a hyperosmotic Ham's (700 mOsm). These findings will guide the eventual development of assisted breeding with cryopreserved sperm contributing to genetic management of this rare species.
authors.affiliation: Department of Reproductive Sciences, Conservation & Research Center, Smithsonian's National Zoological Park, Front Royal, VA 22630, USA. rsantymire@lpzoo.org
authors.forename: Rachel M
authors.initials: RM
authors.lastname: Santymire
authors.forename: Paul E
authors.initials: PE
authors.lastname: Marinari
authors.forename: Julie S
authors.initials: JS
authors.lastname: Kreeger
authors.forename: David E
authors.initials: DE
authors.lastname: Wildt
authors.forename: JoGayle
authors.initials: J
authors.lastname: Howard
mesh_terms: D000177:Acrosome / Q000502:physiology; D000818:Animals; D002470:Cell Survival / Q000187:drug effects*; D003247:Conservation of Natural Resources; D005289:Ferrets / Q000502:physiology*; D005947:Glucose; D007552:Isotonic Solutions / Q000494:pharmacology; D008297:Male; D009994:Osmolar Concentration; D012661:Semen / Q000502:physiology*; D012662:Semen Preservation / Q000379:methods*; D013081:Sperm Motility / Q000187:drug effects; D013094:Spermatozoa / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D014325:Tromethamine
chemical_list: D007552:Isotonic Solutions; C077847:TES-Tris yolk buffer; C083923:nutrient mixture F-10 Ham; D014325:Tromethamine; D005947:Glucose