The Impacts of Mitoquinone Supplementation on Oxidative Status and Cryo-Survival of Cryopreserved Male Donkey (Equus asinus) Semen

This current study aimed to determine the impact of Mitoquinone (MitoQ) on the quality of frozen–thawed donkey semen. Ejaculates were collected from six male donkeys (Equus asinus), and ejaculates were polled and aliquoted into 12 samples. Samples were diluted with TRIS–egg yolk glycerol extender that reached 200 million sperm/mL. After centrifugation, the pellet was diluted at 1:15 with TRIS–egg yolk glycerol extender and divided into the five main groups containing MitoQ with different concentrations: 0 nmol/mL (control; MitoQ0), 100 nmol/mL (MitoQ1), 150 nmol/mL (MitoQ2), 200 nmol/mL (MitoQ3), and 250 nmol/mL (MitoQ4). After thawing, semen quality was evaluated using CASA kinematic parameters, fluorescence microscopy, and biochemical markers such as alanine and aspartate aminotransferase levels (ALT and AST). Malondialdehyde (MDA) and catalase (CAT) levels were also measured. MitoQ1 with 100 nmol/mL significantly increased total motility (p = 0.04), progressive motility (p = 0.04), viability (p = 0.03), kinetic parameters (p = 0.04), linearity (p = 0.02), and straightness (p = 0.04). A significant decline in MDA (p = 0.02), ALT (p = 0.03), and AST (p = 0.03) levels in MitoQ1 with 100 nmol/mL was found, with an elevation of CAT levels (p = 0.02) compared to other concentrations and the control in TRIS–egg yolk glycerol extender. Different concentrations of MitoQ did not affect acrosome and DNA integrity. In conclusion, the addition of MitoQ during cryopreservation has a positive effect on sperm motility, viability, and kinetic parameters, especially at a concentration of 100 nmol/mL when used with a TRIS–egg yolk glycerol extender for frozen–thawed donkey sperm.