Comparative Evaluation of Ascorbic Acid Supplementation in Tris‐Egg Yolk Based Extender and Triladyl® Extender on Post‐Thaw Kinematics Parameters of Sahiwal Bull Semen

The current study was conducted to see the effects of ascorbic acid supplementation into tris-citric acid-glycerol-yolk (TCGY) extender and comparing it with Triladyl extender for bovine semen cryopreserva-tion. Semen was collected from Sahiwal bulls for three weeks and each ejaculate (N=30) was divided into three aliquots. The first aliquot was extended using TCGY extender (control group), the 2nd aliquot was extended using TCGY supplemented with 2.1 mg/mL of ascorbic acid (AA group) and the 3rd aliquot of the same ejaculate was extended using Triladyl extender (TA group). Following the processing and freezing, thawed semen straws from each treatment were evaluated for sperm motility, viability, acrosome integrity and live/dead ratio. The average path velocity was the highest in TA group (77.99±2.99 μm/s) compared with other two groups (P<0.05). Similarly, values of total motility showed that TA group was superior to the other two groups (93.6±0.94% in TA versus 83.33±1.71% in control and 88.53±1.38% in AA group) (P<0.05). The amplitude of lateral head displacement (8.47±0.27 μm versus 5.00±0.22 μm and 4.74±0.13 μm), length of the average path (50.23±1.79 μm vs. 25.33±2.12 μm and 23.51±0.39 μm), length of the cur-vilinear path (85.01±3.03 μm vs. 38.89±1.48 μm and 38.65±0.77 μm), length of the straight-line path (37.28±1.33 μm vs. 19.39±0.84 μm and 20.42±0.29 μm) and track speed (130.93±5.33 μm/s vs. 89.13±3.47 μm/s and 92.11±1.88 μm/s) were significantly higher (P<0.05) in AA group as compared to TA and control group. Values for plasma membrane integrity (PMI), acrosome membrane integrity (AMI) and eosin were higher in AA and TA groups than in the control group (P<0.05). The addition of ascorbic acid in TCGY extender can serve as a better alternative to commercial extender for cryopreservation of semen.