Omaveloxolone supplementation preserves post-thaw turkey sperm quality with higher motility, mitochondrial activity and antioxidant status

Omaveloxolone (Omav) is a pharmacological redox modulator whose effects have not previously been examined during sperm cryopreservation. This study evaluated whether supplementing a modified Lake freezing extender with Omav preserves the post-thaw quality of turkey spermatozoa. On eight independent collection days, ejaculates meeting the quality criteria from ten American Bronze toms were pooled, divided into five equal fractions, and cryopreserved in extender containing 0, 2.5, 5, 10, or 20 nM Omav. Post-thaw total and progressive motility; kinematic variables [average path velocity (VAP), straight-line velocity (VSL), curvilinear velocity (VCL), linearity (LIN), straightness (STR), amplitude of lateral head displacement (ALH), and beat-cross frequency (BCF)]; plasma-membrane functionality; morphology; mitochondrial activity; adenosine triphosphate (ATP); viability and apoptosis-like membrane changes; reactive oxygen species (ROS); superoxide dismutase (SOD); glutathione peroxidase (GPX); and total antioxidant capacity (TAC) were assessed. The 5 nM treatment yielded the highest total motility, VAP, VSL, LIN, ALH, BCF, membrane functionality, mitochondrial activity, ATP content, viability, SOD activity, GPX activity, and TAC, together with the lowest percentages of abnormal morphology, ROS-positive spermatozoa, apoptosis-like spermatozoa, and dead spermatozoa. The 10 nM treatment showed intermediate preservation, whereas 20 nM did not consistently improve outcomes relative to the control. These findings identify 5 nM as the most effective concentration within the tested range for in vitro post-thaw preservation.