LAUSR

Simple Summary In recent years, artificial insemination (AI) using chilled sperm has been one of the most utilized artificial assisted reproductive technologies for dogs. However, changes in temperature can cause oxidative stress, damage sperm structure, and even lead to sperm death. Procyanidin is a polyphenolic compound with antioxidant activity. This study was designed to investigate the effect of procyanidin on canine sperm quality when stored at 4 °C for 72 h. Procyanidin presented improvements in sperm motility, plasma membrane integrity, acrosome integrity, and mitochondrial membrane potential after being stored at 4 °C for 72 h, as well as total antioxidant capacity (T-AOC) and the expression levels of antioxidant-related genes. It could be concluded that the supplementation of procyanidin in the extender improved sperm quality when stored at 4 °C, and the antioxidant capacity of procyanidin could be an important factor in the improvement of sperm quality. Abstract Procyanidin (PC) is a polyphenolic compound with antioxidant activity. The purpose of this study was to determine the influence of PC on canine sperm quality after 72 h of storage at 4 °C. The collected ejaculates were separated into four equal aliquots and treated with various concentrations of PC (0, 10, 30, and 50 μg/mL) in Tris-citric-fructose-egg yolk (TCFE) extender and stored at 4 °C for 72 h. The findings revealed that 30 μg/mL PC was the optimum concentration for significantly improving sperm motility (p < 0.05). Sperm samples treated with 30 μg/mL PC had substantially greater plasma membrane integrity, acrosome integrity, and mitochondrial membrane potential than the control group (p < 0.05). Furthermore, T-AOC and the expression levels of superoxide dismutase 1 (SOD1), catalase (CAT), and glutathione peroxidase 1 (GPx1) genes were significantly higher in sperm treated with 30 μg/mL PC than those in control (p < 0.05). In summary, this study discovered that adding PC to the TCFE extender enhanced sperm quality and that 30 μg/mL PC was the optimal concentration for canine sperm when stored at 4 °C.