40 Coenzyme Q10 supplementation enhanced dairy goat sperm motility, viability, and acrosome integrity after cooling and cryopreservation

Gamete cryopreservation is pivotal for preserving endangered species and disseminating the superior genetics of livestock. However, spermatozoa experience various types of damage during cryopreservation that negatively affects their fertilizing ability. The damage is mainly due to the production of high levels of reactive oxygen species (ROS). Previous studies showed that supplementing extender with coenzyme Q10 (CoQ10), a vital component of the mitochondrial respiratory chain, could improve the fertility of frozen/thawed spermatozoa in various domestic animals; however, little is known about its impacts on goat semen. The objective was to evaluate the impact of CoQ10 supplementation on the quality of dairy goat spermatozoa after cooling or cryopreservation. Semen collected from six mature Alpine bucks twice per week using electroejaculation was diluted to a concentration of 800 × 10⁶ sperm mL⁻¹ in AndroMed extender (Minitube) supplemented with different concentrations of CoQ10 (0, 1, 2, 5, 10, and 20 µM). Diluted semen was either cooled at 4°C for 72 h or cryopreserved. For cryopreservation, semen was equilibrated for 3 h at 4°C and then loaded into 0.25-mm French straws. Straws were then placed 4 cm above liquid N₂ vapor for 10 min before being submerged in liquid N₂ for a week (Morrell et al. 2022 Animals 12, 352). Semen was thawed at 37°C for 30 s. Sperm motility (using CASA), viability (using eosin-nigrosin stain), membrane integrity (by hypo-osmotic swelling; HOS test), and acrosome status (with FITC/PNA stain) were evaluated at 24, 48, and 72 h postcooling and post-thawing. Data were analyzed by one-way ANOVA. The results showed that in cooled semen, sperm motility, percentage of viable sperm, membrane integrity (% of HOS+ sperm), and percentage of sperm with intact acrosome were decreased in a time-dependent manner with the lowest values at 72 h postcooling. However, supplementing semen extender with 5 µM CoQ10 improved (P ≤ 0.05) these parameters at all time points compared with other CoQ10 concentrations. In frozen/thawed semen, sperm motility (46.7 ± 2.7%), percentage of live sperm (49.7 ± 0.5%), percentage HOS+ sperm (47.0 ± 0.9%), and percentage of sperm with intact acrosome (59.7 ± 0.5%) were higher (P ≤ 0.05) in the group supplemented with 2 µM CoQ10 compared with the other CoQ10-supplemented groups. In conclusion, supplementing semen extender with either 2 µM or 5 µM CoQ10 significantly improved the quality of cooled or frozen/thawed goat spermatozoa, respectively. These findings suggest the positive impact of CoQ10 in protecting dairy goat spermatozoa against cooling and freezing damage.

This work was supported by a USDA/NIFA 1890 Capacity Building Grant (Award 2022-38821-37343).