Breed of Boar Influences the Optimal Concentration of Gamma-oryzanol Needed for Semen Cryopreservation

Contents: The aim of this study was to investigate the influence of boar breed on the optimal concentration of gamma-oryzanol on the qualities of cryopreserved boar semen. Semen was collected from 20 boars (10 Duroc, 5 Large white and 5 Landrace boars). The semen sample was divided into five groups (A-E) according to the concentration of gamma-oryzanol in extender II, that is 0, 0.08, 0.16, 0.24 and 0.32 mm, respectively. The semen was cryopreserved by nitrogen vapour and storage in nitrogen tank (-196°C). After storage for a week, samples were thawed at 50°C for 12 s and evaluated for progressive motility, sperm viability and acrosome integrity. The results demonstrated that gamma-oryzanol significantly improved progressive motility, viability and acrosome integrity of frozen-thawed boar semen. Considering the influence of breeds on the optimal concentration of gamma-oryzanol, for Duroc boar, gamma-oryzanol at 0.16 mm (group C) yielded the highest percentage of progressive motility, sperm viability and acrosome integrity. For Large white and Landrace boars, gamma-oryzanol at 0.24 mm (group D) showed a significantly higher percentage of progressive motility, viability (not significant in Landrace) and acrosome integrity than other concentrations. In conclusion, the optimal concentration of gamma-oryzanol needed for boar semen cryopreservation in lactose-egg yolk (LEY) freezing extender is not only depended on individual boar but also breed of boar, that is 0.16 mm for Duroc and 0.24 mm for Large white and Landrace.