Effect of hydroxytyrosol on sperm post-thaw motion and velocity of cryopreserved ram semen

A study was undertaken to evaluate hydroxytyrosol (HT), a natural component of olive mill waste as an additive/antioxidant in TES Tris-Glycerol-Yolk (TEST-G-Y) extender for cryopreservation of ram semen. Pooled semen samples (n=9) from eight Malpura rams were diluted with TEST-G-Y containing 0, 30, 80, 150 and 300 μM HT thereby making sperm concentration of 1000 million/ml. Diluted semen samples were cooled to 5°C in French ministraws for equilibration and later the straws were frozen by programmable cell freezer. Semen samples were evaluated at post-thaw state by Computer-Assisted Sperm Analysis (CASA). Significantly (P<0.05) higher total sperm motility (67.76±3.41%) and rapid velocity (42.19±2.45%) were observed in semen with 80 μM HT than 0μM HT (58.42±1.64 and 32.44±2.75%), 30μM HT (62.33±3.23 and 37.69±2.37%), 150μM HT (65.02±3.96 and 36.53±3.69%) and 300μM HT (61.65 and 38.08±2.83%) groups. Velocity and relative velocity characteristics differed non-significantly (P>0.05). The present results suggested that the HT supplementation at 80 μM has preserved better the total sperm motility and rapid velocity in post-thaw ram semen.