Magnetized water is defined as water that has passed through a magnet and shows increased permeability into cells and electron-donating characteristics. These attributes can protect against membrane damage and remove reactive oxygen species (ROS) in mammalian cells. We explored the effects of improved magnetized semen extenders containing bovine serum albumin (BSA) as antioxidants on apoptosis in boar sperm. Ejaculated semen was diluted in magnetized extender (OG and 6000G) with or without BSA COG + BSA and 6000G + BSA), and sperm were analyzed based on viability, acrosome reaction, and H2O2 level of live sperm using flow cytometry. Sperm were then preserved for 11 days at 18 degrees C. We found that viability was significantly higher in 6000G + BSA than under the other treatments (P < 0.05). The acrosome reaction was significantly lower in the 6000G + BSA group compared with the other treatments (P < 0.05). Live sperm with high intracellular H2O2 level were significantly lower in the 6000G + BSA group than under other treatments (P < 0.05). Based on our results, magnetized extenders have antioxidative effects on the liquid preservation of boar sperm. (C) 2015 Elsevier Inc. All rights reserved.