Pretreatment of Addra gazelle (Nanger dama ruficollis) spermatozoa with cholesterol-loaded cyclodextrins improves cryosurvival.

The Dama Gazelle, Nanger dama ruficollis, is critically endangered largely due to over-hunting and poaching. Fewer than 500 animals remain in the wild and ∼134 individuals are managed in captivity in North American zoos as a ’hedge’ against extinction. The ability to preserve and transport gene diversity could be enhanced through the use of frozen-thawed sperm and artificial insemination. Our aim was to assess the beneficial effects of cholesterol-loaded cyclodextrin (CLC) on dama gazelle sperm cryosurvival. Electroejaculates from three male dama gazelle were evaluated for total motility, forward progressive status, concentration, and acrosomal membrane integrity. Ejaculates were diluted (120 × 10 6  sperm/ml) with Ham’s F10 supplemented with Hepes (Irvine Scientific), aliquoted into five 1.5 ml eppendorf centrifuge tubes and incubated (37 °C; 15 min) with 0, 0.5, 1.5, 3.0 and 6.0 mg/ml CLC, respectively. Aliquots were centrifuged (300 g ; 8 min) and the resulting sperm pellets were resuspended (250 × 106 sperm/ml) in TEST-Yolk Buffer Refrigeration Medium (Irvine Scientific) containing 6% (v/v) glycerol. Sperm suspensions were loaded in straws (0.25 ml), cooled to 5 °C and placed 4 cm over liquid nitrogen (LN2) for 10 min before being plunged into LN2. Straws were thawed at 37 °C (30 s), stored protected from light at 25 °C and evaluated for total motility, progressive status, and acrosomal integrity at 0 (immediately post-thaw), 1, 2 and 3 h. Data were analyzed using generalized linear regression models and significance was defined as P P P P P P Source of funding: None declared. Conflict of interest: None declared. pukazhenthib@si.edu