Capacitation and Acrosome Reaction Induction on Thawed Dama dama Deer Spermatozoa: Glycine Effect as Cryopreservation Diluent Supplement

The aim of this research was to evaluate two different diluents for sperm cryopreservation and to study functional parameters in relation to the response to heparin, lysophosphatidylcholine and progesterone, in frozen-thawed semen of fallow deer (Dama dama) during the reproductive season (brama). In this way, fallow deer can be used as a biological model of endangered cervids. Semen was obtained by electroejaculation. Heparin, progesterone and lysophosphatidylcholine were used as capacitation and acrosome reaction inducers, respectively. Capacitation and acrosome reaction were evaluated by chlorotetracycline epifluorescence technique (CTC), membrane integrity by Hypo-osmotic swelling test (HOS) and viability and acrosome integrity by trypan blue stain/DIC. Data was analyzed by ANOVA and Tukey Test (P < 0.05). Semen was cryopreserved in different diluents and Fructose-Tris-Glycine extender was selected. Capacitation with heparin at different incubation times determined that the highest capacitation percentage was obtained at 45 minutes incubation. Progesterone (1 mu M) and lysophosphatidylcholine in heparin capacitated sperm induced acrosome reaction (P < 0.05). This study contributes to improve cryopreservation methods and to increase the knowledge about capacitation and acrosome reaction in vitro in deer spermatozoa, allowing an advance in the development of reproductive biotechnologies.