Effect of adding anethole to the cryopreservation medium (powdered coconut water) on morphology, kinetics, and oxidative stress of buck sperm

The quality of post-thawing goat sperm is critical to the success of artificial insemination protocols and may be influenced by extenders, cryoprotectants, and antioxidant substances. Therefore, the objective of this study was to evaluate the effects of the antioxidant anethole on goat sperm diluted in preservation medium based on powdered coconut water (ACP-101c) and frozen. For that, each ejaculate was submitted to the following treatments: ACP-101c (control); control plus supplementation with 30, 300, or 2000 μg/mL anethole. The samples were thawed and evaluated for morphology, kinetics, membrane integrity, and reactive oxygen species (ROS). The addition of anethole increased morphological abnormalities (P < 0.05), however, it did not affect sperm kinetics. Flow cytometry analysis showed that sperm cells cryopreserved with 300 μg/mL anethole had lower acrosome integrity than those cryopreserved in other treatments. Evaluation of oxidative stress revealed that cells stored in the presence of 2000 μg/mL anethole had small amounts of ROS when compared to those preserved in the control medium alone or supplemented with 300 μg/mL anethole (P < 0.05). After cryopreservation of sperm with 2000 μg/mL anethole, the highest percentage of viable sperm without ROS was observed (P < 0.05). In conclusion, despite reducing ROS levels, the supplementation of anethole in ACP-101c did not affect sperm kinetics or membrane integrity post-thawing, however, it did cause morphological damage to sperm.