Dose-Dependent Effects of Clinoptilolite Supplementation on Sperm Quality and Oxidative Stress During Canine Semen Cryopreservation.

BACKGROUND

Cryopreservation induces oxidative stress, leading to reduced semen quality in canine semen. Clinoptilolite (CLP), a natural zeolite, has potential antioxidant properties that may improve post-thaw sperm parameters.

OBJECTIVES

This study aimed to evaluate the dose-dependent effects of CLP supplementation in semen extenders on sperm quality and oxidative stress in dogs.

METHODS

Semen was collected from four adult dogs by manual manipulation, divided into five equal aliquots, and diluted at a ratio of 1:3 (v/v) with a Tris-citrate extender containing 0% (control), 1%, 2%, 3%, or 4% CLP. Samples were cooled to 5°C within 45 min, equilibrated for 2 h in 0.25 mL straws, frozen in liquid nitrogen vapour, and stored in liquid nitrogen. Samples were thawed at 37°C for 30 s. Post-thaw sperm quality was evaluated together with oxidative stress markers, including total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI).

RESULTS

The 2% CLP group showed the highest post-thaw sperm quality, whereas the lowest performance was observed in the 4% CLP group. Additionally, the 2% CLP group exhibited a more favourable oxidative profile, with higher TAS and lower TOS and OSI values than all other groups.

CONCLUSIONS

CLP supplementation exerted dose-dependent effects on sperm quality and oxidative balance in canine semen cryopreservation. A 2% CLP concentration appears to be the most effective for improving post-thaw sperm quality.