Sperm quality improvement of cryopreserved boar semen through colloidal centrifugation gradient

Boar semen cryopreservation islimited due tothe lower thermal shock resistance ofsperm cells. Acolloidal centrifugation gradient isanenhancement tocryopreservation that could improve the frozen boar semen quality. Cryopreserved boar semen quality was evaluated using acommercial colloidal centrifugation gradient. Atotal of15ejaculates from 5boars were evaluated across two treatments: acontrol without colloidal centrifugation and atreatment with commercial colloidal centrifugation. Amanual freezing method used two freezing curves inliquid nitrogen. Sperm motility was assessed byComputer-Assisted Semen Analysis, aswell assperm capacitation-like membrane destabilisation at30min and 150 min after thawing using Merocyanine 540 (M540) for samples incubated at37C. Spectrophotometry measured lipid peroxidation indirectly bythe amount ofmalondialdehyde; reactive oxygen species production was also determined for sperm samples incubated for 30minutes. The gradient centrifugation treatment improved ejaculate sperm motility and membrane destabilisation. The proportion ofmorphologically normal sperm was higher inthe gradient than inthe control. Atotal of74% ofspermatozoa retained normal morphology. Lipid peroxidation was lower inthe colloidal centrifugation treatment. MDA was lower with gradient (16.4± 2.5 vs 22.3± 2.5µmol/30 106sperm; P<0.05). Intracellular reactive oxygen species (ROS) and M540 positivity did not differ significantly between the treatments ateither time point. The centrifugation process improved the quality parameters offrozen boar semen after thawing.