title: Development of a sperm cryopreservation protocol for the Argentine black and white tegu (Tupinambis merianae).
abstract: Of the 934 lizard species evaluated by the International Union for the Conservation of Nature (IUCN), at least one-third is threatened with extinction. However, there are no reports of semen cryopreservation efforts for lizards. Invasive Argentine black and white tegus were captured in the Florida Everglades, and sperm was collected postmortem. Initial motility score (IMS; % motile × speed of progression2× 100), plasma membrane integrity (IPL), and acrosome integrity (IAC) were recorded. Sperm was diluted in TEST-yolk buffer with a final glycerol or dimethylsulfoxide (DMSO)concentration of 8%, 12%, or 16%, and frozen at 0.3 °C, 1.0 °C, or 6.3 °C/min. At thaw, all variables were expressed as the percentage of initial (%IMS, %IPL, and %IAC). The 0.3 °C freeze rate was more successful than 1.0 °C and 6.3 °C/min in preserving %IMS and %IPL. DMSO preserved %IMS, %IPL, and %IAC better than glycerol. To determine the best overall cryopreservation protocol, a sperm quality index was calculated, giving equal weight to each of the three indicators of cryosurvival. Because there were significant interactions between freeze rate and cryoprotectant concentration, each treatment was compared with all others. The sperm quality index analysis revealed that tegu sperm frozen at 0.3 °C/min with 12% DMSO exhibited the highest postthaw viability compared with all other treatments.
authors.affiliation: Reproductive Physiology Division, San Diego Zoo Institute for Conservation Research, Escondido, California, USA. Electronic address: cyoung@sandiegozoo.org.
authors.forename: Carly
authors.initials: C
authors.lastname: Young
authors.affiliation: Reproductive Physiology Division, San Diego Zoo Institute for Conservation Research, Escondido, California, USA.
authors.forename: Nicole
authors.initials: N
authors.lastname: Ravida
authors.affiliation: Reproductive Physiology Division, San Diego Zoo Institute for Conservation Research, Escondido, California, USA; Fort Lauderdale Research and Education Center, University of Florida, Fort Lauderdale, Florida, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Curtis
authors.affiliation: Fort Lauderdale Research and Education Center, University of Florida, Fort Lauderdale, Florida, USA.
authors.forename: Frank
authors.initials: F
authors.lastname: Mazzotti
authors.affiliation: Fort Lauderdale Research and Education Center, University of Florida, Fort Lauderdale, Florida, USA. Electronic address: bdurrant@sandiegozoo.org.
authors.forename: Barbara
authors.initials: B
authors.lastname: Durrant
mesh_terms: D000177:Acrosome / Q000502:physiology; D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D015925:Cryopreservation / Q000662:veterinary*; D008116:Lizards / Q000502:physiology*; D008297:Male; D055101:Semen Analysis; D012662:Semen Preservation / Q000662:veterinary*; D013094:Spermatozoa / Q000502:physiology
keywords: Endangered species; Freezing; Lizard; Reptile; Semen