Background: The effects of α-tocopherol on intracellular Ca2+ intensity in semen cryopreservation by regulate intracellular Ca2+ intensity have not been reported yet. Objective: The research was conducted to evaluate the effect of supplementation α-tocopherol into egg yolk skim milk extender on sperm quality and intracellular Ca2+ intensity. Methods: Semen samples were collected and supplemented with respectively 0mM (P0); 0.5mM (P1); 1mM (P2); 1.5mM (P3) and 2mM (P4) α-tocopherol in extender before cryopreservation processes. Post-thawing sperm was evaluated for motility, viability, and abnormality using Phase Contrast Microscope (200x) with eosin-nigrosine staining, and intracellular Ca2+ intensity of the best result dose was evaluated using Confocal Laser Scan Microscope (400x) with Fluo-3 Staining. Results: The results showed there was a significant difference (P≤0.05) in sperm motility and viability between P0; P1 with P2; P3; P4. The Motility and viability between groups P0; P1 and P3; P4 showed no significant difference (P≥0.05), while P2 with P3; P4 showed significant difference (P≤0.05). There was a significant difference (P≤0.05) in sperm abnormality of P0; P1 with P2; P3; P4. The abnormality between P0; P1 and P2; P3 showed no significant difference (P≥ 0.05), while P2; P3 showed a significant difference with P4 (P≤0.05). The best result in sperm quality was supplementation with 1.5mM α-tocopherol. Ca2+ intracellular intensity: 142.76 ± 21.8 au (P0) and 176.06 ± 61.43 au (P3). Conclusions: It was concluded that 1.5mM α-tocopherol is the best dose to improve sperm quality by regulating intracellular Ca2+ intensity on Simmental bull cattle.

Semen storage in cold temperatures might cause an increase in reactive oxygen species (ROS) production. This condition resulted in spermatozoa damage and quality decrease. This study was conducted to investigate the effects of α-tocopherol supplementation in diluents on the motility, viability, and plasma membrane integrity of Simmental bull spermatozoa after cooling. Semen samples were diluted in skim milk egg yolk supplemented with 0, 0.5, 1.0, and 1.5 mM α-tocopherol respectively for control, Tl, T2, and T3. Spermatozoa were evaluated for their motility, viability, and membrane integrity in cooling temperature (5°C). The daily evaluation showed that 1.5 mM α-tocopherol was the best in maintaining motility, viability, and plasma membrane integrity, while 1.0 mM α-tocopherol was only good for maintaining viability. Therefore, it can be concluded that α-tocopherol at the concentration of 1.5 mM was an efficient antioxidant supplement for Simmental cattle semen in skim milk egg yolk diluent.