Use of a one-step freezing protocol for boar sperm with distinct cryoprotectants

ABSTRACT: The present study evaluated the cryoprotectant efficacy of dimethylacetamide (DMA) and ethylene glycol in a one-step protocol to freeze boar sperm. sperm-rich portion ejaculates from two boars were collected once week, for 10 weeks. After collection, diluted (1:1; v/v) cooling extender. determining their spermatozoa concentration, pooled with same number each stabilized at 20°C 120 min. Distinct cryoprotectants added extender 20 °C, different concentrations, composing six treatments: 1.25% 2.5% glycerol (control); glycol; 5.0% DMA. samples stored 0.25 mL straws, containing 35 × 106 spermatozoa. 90 min straws submitted curve until 5 °C (0.3 0.5 °C/min) kept 5°C 60 Freezing was conducted by placing horizontally cm above liquid nitrogen min, followed immersion on nitrogen. thawing 37 30 seconds, sperm quality through computer-assisted semen analysis system flow cytometry. Sperm motility greater (P< 0.05) treatments DMA (22.2 ± 2.6% 20.0 2.8%, respectively) than treatment (8.2 1.0%). integrity plasma membrane (P = 0.08) mitochondrial potential 0.27) similar among treatments. least efficient maintain intact acrosome 0.01). Some kinetics parameters (DAP, DCL, DSL, VAP, VCL, VSL e ALH) positively affected freezing resulted unsatisfactory after thawing, regardless cryoprotectant.