Improving rooster semen cryopreservation with telmisartan-enhanced extender

Semen cryopreservation is essential for preserving genetic resources and enabling artificial insemination in poultry breeding. However, avian sperm is known to experience detrimental changes during the freezing process. Telmisartan, an angiotensin-II receptor antagonist recognized for its antioxidant properties and ability to activate AMP-activated protein kinase (AMPK), was hypothesized to improve post-thaw semen quality by enhancing mitochondrial function and providing antioxidant protection to sperm. The current study was conducted to determine the effect of a semen extender containing different levels of Telmisartan on post-thaw rooster sperm quality indices. Ten 30-week-old broiler breeder roosters (Cobb 500) provided semen samples, which were pooled and diluted with extenders containing varying Telmisartan concentrations (0, 7.5, 15, 22.5, 30 µg/ml). The samples were cryopreserved and later evaluated for motility, membrane integrity, mitochondrial activity, antioxidant capacity, and apoptotic-like changes. The addition of Telmisartan at 7.5 and 15 µg/ml significantly improved total motility (TM), progressive motility (PM), average path velocity (VAP), straight linear velocity (VSL), and curvilinear velocity (VCL) compared to the control. The highest improvement was observed at 15 µg/ml, which also showed increased membrane integrity and mitochondrial activity while reducing apoptotic and dead sperm percentages. Antioxidant assays revealed elevated glutathione peroxidase (GPx) and total antioxidant capacity (TAC) levels, alongside decreased malondialdehyde (MDA) levels in the 15 µg/ml group. Higher Telmisartan concentrations (22.5 and 30 µg/ml) did not yield additional benefits and, in some parameters, performed similarly to the control group. The study concludes that Telmisartan, at an optimal concentration of 15 µg/ml, enhances the cryopreservation outcomes for rooster semen by improving motility, mitochondrial function, and antioxidant defense while reducing lipid peroxidation and apoptosis. These findings suggest potential for better fertility rates in poultry breeding programs utilizing Telmisartan-enhanced extenders for semen cryopreservation. Further research is recommended to explore the broader implications of these results on reproductive performance.