INRA96 Supplemented With Phospholipids Liposomes, A Promising Approach for Stallion Sperm Chilling

Among biotechnologies of reproduction in the equine species, artificial insemination remains the most used technology especially for cooled transported sperm. Although the use of INRA96 extender has demonstrated its efficiency for long-term sperm storage at 4°C or 15°C, some stallions ("bad coolers") are excluded from such technology. Some years ago, we demonstrated that liposomes produced from egg yolk (EY) phospholipids could be an alternative to egg yolk plasma in stallion freezing extenders. To develop a new extender for sperm chilling, we evaluated the protective effect of liposomes produced from EY phospholipids on stallion sperm storage at 4°C. The sperm of stallions from two studs was diluted in INRA96 extender (as control) or an experimental extender (EE) composed of INRA96 supplemented with liposomes of EY phospholipids. After 24H (D1), 72H (D3), and 6 days (D6) or 7 days (D7), motility parameters were evaluated using Computer Assisted Semen Analyzer. Our results demonstrated that total and progressive motility decreased significantly after dilution and storage in INRA96 between D1 and D3 (P < .05) while no significant decrease was observed between D1 and D3 with EE. Regarding VAP parameter, no significant difference was observed between extenders except at D7 in stud 2. Moreover, total and progressive motility were maintained at a significantly higher level (D3, D6, D7) when sperm was stored in EE compared to INRA96. These promising results demonstrate that the supplementation of INRA96 extender with egg-yolk phospholipids liposomes allows a higher protection to stallion sperm cells.