title: Giant panda (Ailuropoda melanoleuca) spermatozoon decondensation in vitro is not compromised by cryopreservation.
abstract: Natural breeding of giant pandas in captivity is compromised, making artificial insemination and spermatozoa cryopreservation essential for genetic management. This study examined the influence of freeze-thawing on traditional parameters such as motility and spermatozoon functionality, specifically decondensation in vitro. Giant panda spermatozoa were assessed before and after rapid cryopreservation (4 degrees C to -130 degrees C over 2 min) in liquid nitrogen vapour. Spermatozoa pre-incubated in medium for 6 h were co-incubated with cat zonae (2 zonae microL(-1)) for 30 min to effect capacitation and an acrosome reaction. Spermatozoa were then mixed with mature cat oocyte cytoplasm (2 cytoplasm microL(-1)) for 4 h and evaluated for decondensation. Frozen spermatozoa were less motile (P < 0.05) than fresh counterparts immediately post-thawing, but not after 6 h incubation. There were more (P < 0.05) spermatozoa with completely diffused chromatin post-thaw (10.4 +/- 1.3%; mean +/- s.e.m.) compared to fresh counterparts (5.1 +/- 1.0%). However, there was no overall difference (P > 0.05) in the incidence of decondensation between fresh (4 h, 69.8 +/- 5.9%) and thawed (4 h, 71.5 +/- 4.9%) spermatozoa after exposure to cat oocyte cytoplasm. It is concluded that the 'rapid' method now used to cryopreserve giant panda spermatozoa has little impact on spermatozoon decondensation.
authors.affiliation: Conservation and Research Center, Smithsonian's National Zoological Park, Front Royal, VA 22630, USA. spindler@uoguelph.ca
authors.forename: Rebecca E
authors.initials: RE
authors.lastname: Spindler
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.forename: Jo Gayle
authors.initials: JG
authors.lastname: Howard
authors.forename: Peng Yan
authors.initials: PY
authors.lastname: Wang
authors.forename: Hemin
authors.initials: H
authors.lastname: Zhang
authors.forename: Guiquan
authors.initials: G
authors.lastname: Zhang
authors.forename: David E
authors.initials: DE
authors.lastname: Wildt
mesh_terms: D000818:Animals; D015925:Cryopreservation / Q000379:methods; D008297:Male; D012662:Semen Preservation / Q000379:methods; D013094:Spermatozoa / Q000166:cytology*; D001503:Ursidae