Effects of negative pressure applied before storage (liquid storage, 17°C) on boar semen quality and fertilization ability

The present study was aimed to investigate the effects of negative pressure applied before storage on the quality and fertilization ability of boar semen. Boar semen samples were collected and pooled and diluted with Modena solution containing 0.4% (w/v) of bovine serum albumin. Negative pressure was applied for 2-5 min using a vacuum pump with a barometer. The pressure applied were 0 (Control), -0.02 MPa (P200), -0.04 MPa (P400) and -0.08 MPa (P800). The sperm motility, acrosome integrity and sperm fertilizing ability were evaluated. Application of -0.04 MPa improved the sperm motility, acrosome integrity and fertilizing ability, compared with the other groups. The sperm motility and acrosome integrity decreased with increasing storage time in vitro. After 5 days, the sperm motility and acrosome integrity of the P400 group were all higher than those of the other groups (P < 0.05). The cleavage rate (64.5% ± 2.4%) and blastocyst development rate (33.9% ± 2.8%) for semen stored for 7 days were similar to those of fresh semen. In conclusion, application of -0.04 MPa before liquid storage at 17°C can improve the quality and fertilization ability of boar semen.