Enhancing cryopreserved ram sperm quality at -80 °C with Spirulina platensis and Salvia verbenaca extracts

This study was conducted in two steps to evaluate the influence of freezing methods and natural extracts on cryopreserved ram sperm quality. Initially, the research compared the effects of two freezing methods: liquid nitrogen (LN2) versus -80 °C, on post-thawed ram semen on total and progressive motilities and velocity parameters. Experiment I revealed no significant differences (P > 0.05) between the LN2 and -80 °C freezing methods, indicating similar effects on the analyzed parameters. Experiment II aimed to examine the influence of Spirulina platensis (SP) and Salvia verbenaca (SV) extracts added to egg yolk extender on cryopreserved sperm quality, utilizing the -80 °C freezing method. Various concentrations (1.25, 3.75, 6.25 and 8.75 µg*mL-1) of acetone (Ac-SP and Ac-SV) and hexanoic (Hex-SP), as well as methanolic (MeOH-SV) extracts, were added into the extender. A thorough assessment of post-thawed sperm quality parameters, encompassing motility, velocity parameters, viability, membrane integrity, abnormality and lipid peroxidation was conducted. The outcomes demonstrated that 1.25 and 3.75 g*mL-1 of Ac-SP and Hex-SP and 1.25 µg*mL-1 of AC-SV and MeOH-SV increased the post-thawed ram sperm quality. In conclusion, this study emphasizes the antioxidant properties of SP and SV extracts, highlighting their potential to protect cryopreserved sperm cells from oxidative stress at -80 °C.