Antioxidant astaxanthin enhances cryosurvival and post-thaw functional parameters of rabbit spermatozoa

This study evaluated the effect of astaxanthin (AX), a potent antioxidant carotenoid, on the post-thaw quality of cryopreserved rabbit sperm. Semen samples were frozen with AX supplementation at concentrations of 0 (CONTROL), 0.5, 1, or 2 μM. Post-thaw sperm quality was assessed by computer-assisted sperm analysis (CASA) for motility, and by flow cytometry to evaluate viability, early apoptosis, mitochondrial activity, reactive oxygen species (ROS) levels, and acrosomal membrane integrity. Supplementation with 0.5 and 1 μM AX significantly improved total motility, viability, and mitochondrial activity compared to the control group (p < 0.05). These concentrations also led to significantly reduced levels of apoptotic cells and ROS. Acrosomal damage was not significantly affected by AX supplementation. These findings demonstrate that low-dose AX addition during cryopreservation attenuates oxidative and apoptotic damage in rabbit spermatozoa and enhances several key post-thaw quality parameters. Astaxanthin may thus represent a promising additive for improving cryosurvival in rabbit sperm used for assisted reproduction.