Inclusion of Spirulina platensis and Salvia verbenaca extracts to boost semen quality and fertilization ability in sheep

The aim of this study was to investigate the effect of Spirulina platensis (SP) and Salvia verbenaca (SV) extracts added to skimmed milk (SM) extender on ram sperm quality and fertility. Semen was collected using an artificial vagina, extended in SM to reach a final concentration of 0.8 × 10⁹ spermatozoa/mL, stored at 4°C and evaluated at 0, 5 H and 24 H. The experiment has been performed in three steps. Firstly, from four extracts (methanol: MeOH, acetone: Ac, ethyl acetate: EtOAc and hexane: Hex) of SP and SV, only acetonic and hexanoic extracts of SP and acetonic and methanolic extracts of SV showed the highest in vitro antioxidant activities and were then selected for the following step. Thereafter, the effects of four concentrations (1.25, 3.75, 6.25, and 8.75 μg/mL) of each selected extract on stored sperm motility were evaluated. The output of this trial led to select the best concentrations having beneficial effects on sperm quality parameters (viability, abnormalities, membrane integrity, and lipid peroxidation) and fertility after insemination. The results showed that the same concentration (1.25 μg/mL) of both Ac-SP and Hex-SP, as well as 3.75 μg/mL of Ac-SV and 6.25 μg/mL of MeOH-SV, maintain all sperm quality parameters at 4°C during 24 H of storage. Besides, no difference was found in fertility between the selected extracts and the control. In conclusion, SP and SV extracts were shown to improve the quality of ram sperm and to maintain fertility rate after insemination as similar or competitive to many previous studies published in the field.