Effect of nicotinic acid on the plasma membrane function and polyunsaturated fatty acids composition during cryopreservation in boar sperm

This study was conducted to evaluate the effect of nicotinic acid on plasma membrane integrity and fatty acid composition in frozen–thawed boar sperm. Boar semen was cryopreserved using freezing extender containing nicotinic acid (NA), then plasma membrane integrity, osmotic equilibration, lipid peroxidation and fatty acid were analysed. The plasma membrane integrity of frozen–thawed sperm was significantly higher in the 10 mM NA than in the 0 and 20 mM NA treatment groups (p < 0.05). Additionally, the osmotic equilibration ability was not different in treatment groups, but lipid peroxidation was significantly decreased in the 10 mM NA treatment group (p < 0.05). The saturated fatty acids were significantly decreased in the 10 mM NA treatment group, and C18:1n‐9, C18:2n‐6, C20:4n‐6, C22:5n‐6 and C22:6n‐3, and total polyunsaturated fatty acids (PUFAs) were significantly increased in the 10 mM NA treatment groups (p < 0.05). In summary, 10 mM NA improved plasma membrane integrity, inhibited lipid peroxidation and increased PUFAs in frozen–thawed boar sperm. These results suggest that NA may be useful to protect the plasma membrane and inhibit the loss of PUFAs for sperm cryopreservation in pigs.