Abstract
The objective of this study was to establish the optimal conditions for hypoosmotic swelling (HOS) test to assess the functional integrity of the membranes of boar fresh or frozen/thawed spermatozoa. When pooled semen sample was incubated for 30 min at $37^{\circ}C$ with different test solution of varied osmolarity, the highest percentage of HOS positive spermatozoa was observed in a 150 mOsmol fructose/Na-citrate solution (33.6%). Incubation time did not affect significantly the score of HOS positive spermatozoa observed in a 150 mOsmol fructose/Na-citrate solution at $37^{\circ}C$, but the osmolarity affected the score of HOS positive spermatozoa under the same condition above. Fresh semen was significantly better than frozen/thawed semen in semen parameters evaluated such as motility, viability, membrane integrity and lipid peroxidation (p<005). In the relationships of sperm parameters, motility vs viability, motility vs membrane integrity and viability vs membrane integrity were positively correlated ($0.82{\sim}0.94$) but lipid peroxidation vs other estimated factors was negatively correlated ($- 0.90{\sim}- 0.98$). Among the evaluation methods, motility vs Viability, motility vs membrane integrity and lipid peroxidation vs other estimated factors were significantly correlated (p<0.05). These results of this. study indicate that the optimal condition of HOST in boar spermatozoa is a 150 mOsmol fructose/Na-citrate solution for 30 min incubation at $37^{\circ}C$ and HOST can substitute the examination of motility, viability and lipid peroxidation.
