Plasma membrane integrity
Sperm membrane integrity was determined by double-fluorescent labeling technique, according to the protocol described by Partyka et al.[34]. Briefly, 300 µL of the diluted samples were stained with 5µL of SYBR-14 (commercial solution diluted 50-fold) and 5µL of PI. The PI negative and SYBR-14 positive population showing green fluorescence was considered live, with sperm plasma membrane intact (PMI).