Soybean Phospholipids-Based Extender as an Alternative for Bull Sperm Cryopreservation

Abstract

This current work investigated the usage of soybean phospholipid (SP) in extenders for bull sperm cryopreservation. The sperm was obtained from Friesian Holstein (FH) bulls using an artificial vagina method. Furthermore, semen samples were pooled and diluted in a Tris egg yolk-based extender (control group; CG) or Tris extender supplemented with SP at different concentrations (G1 = 0.5%, G2 = 1%, G3 = 1.5%, G4 = 2%, G5 = 2.5%) for a final concentration of 25°106 spermatozoa/0.25 mL. Subsequently, they were packed in straws (0.25 mL), cryopreserved using liquid nitrogen vapor for 10 minutes, then stored in liquid nitrogen (-196°C). As a result, control group presented significantly higher values in motility, viability and membrane integrity at the stage of dilution, equilibration and post-thawing compared to treatment group (P<0.05). After thawing (37°C/30s), no significant difference was observed between G4 and control group for all parameters observed using Computer Assisted Sperm Analysis (CASA) (P>0.05). In conclusion, the addition of 2% soybean phospholipid in Tris-based extender can be used for freezing bull semen, producing a satisfied fertility rate in post-thawing stage.