The present study aimed to determine the effect of adding Quercetin in Dimitropoulos (DM)
extender on the Sperm characteristics and biochemical parameters of equine semen at 5 °C.
Three fertile Arabian stallions were used in this study continued for eight consecutive weeks (from
August to September 2021). Semen collected twice weekly (n= 48) by Missouri artificial vagina was
aliquoted and diluted with DM extenders containing different concentrations of Quercetin (0 µM
(control), 25 µM, 50 µM, and 100 µM) to a final concentration of 25×106 sperm/ml. All groups were
kept at 5 ºC and evaluated daily (every 12 hours) for three days for motility, livability, total
abnormality, metabolic enzymes (ACP, ALP, AST), lactate dehydrogenase (LDH), acrosine activity,
antioxidants (CAT, SOD, GPx), and lipid peroxidation (MDA). The results revealed that Quercetin at
a concentration of 50 µM has an improving effect on sperm motility at 36 and 48 hrs post-chilling. In
addition, it lowered extracellular ACP and enhanced catalase enzyme activities, and lowered MDA
accumulation throughout the experiment. In conclusion, adding quercetin at a concentration of 50
µM has a potential protective effect on sperm motility and decreases oxidation-reduction during cold
storage of stallion semen.