Buffalo spermatozoa are more sensitive for cryopreservation compared to other species.
This study aimed to evaluate the consequences of quercetin against cryodamage of
buffalo frozen–thawed spermatozoa characteristics. Semen of Egyptian bulls (n = 4) was
extended in OptiXcell extender incorporated with quercetin at 0 (control), 2.5, 5.0, 10.0,
20.0, 40.0, and 80.0μM before cryopreservation. Frozen–thawed semen was evaluated
for sperm motility by computer-assisted sperm analyzer (CASA), viability, morphology,
membrane, and acrosome integrities. The kinematics parameters including average
path velocity (VAP; μm/s), straight linear velocity (VSL; μm/s), curvilinear velocity (VCL;
μm/s), amplitude of lateral head displacement (ALH; μm), beat cross frequency (BCF;
Hz), linearity [LIN, (VSL/VCL) × 100], and straightness [STR, (VSL/VAP) × 100] were
assessed. The sperm-free extender was evaluated for aspartate aminotransferase (AST),
alanine aminotransferase (ALT), and H2O2. Homogenized sperm cells were evaluated for
oxidative stress biomarkers [superoxide dismutase (SOD), catalase (CAT), glutathione
peroxidase (GPX)], and lipid peroxidation [malondialdehyde (MDA)]. The highest values
of total motility, progressive motility, viability, intact acrosome, and membrane integrity
substantially improved with 10μMof quercetin. STR (%) was substantially low (P < 0.01),
and VCL (μm/s) and ALH (μm) were markedly high (P < 0.05) in 10μM of quercetin. The
outflow of ALT enzyme to extracellular fluid was lower with 10μMof quercetin (P < 0.001)
and higher at 2.5μM of quercetin. The spermatozoa leaked AST was markedly lower
at 5.0, 10 (P < 0.001) and 20μM (P < 0.05) of quercetin. The activity of antioxidant
enzymes was eminently low at all quercetin concentrations, and this was accompanied
by the decrease in H2O2 in the media. SOD activity at 10–80μM, CAT at 5.0–40μM,
and GPX at 2.5–80.0μM of quercetin in spermatozoa were substantially low. MDA level
significantly (P < 0.001) decreased at all quercetin concentrations. In conclusion, the
incorporation of quercetin at the level of 10μM is promising in improving buffalo semen
characteristics and lower the freezing–thawing oxidative stress.