Protective Effects of Betaine on Boar Sperm Quality during Liquid Storage and Transport

Simple Summary Liquid-preserved boar semen is widely used in the pig breeding industry. Preservation and transportation can affect the fertilizing ability of sperm, reducing the efficiency of artificial insemination. Betaine, a natural plant extract, has been shown to benefit male fertility. However, it remains unclear whether it exerts a protective effect on liquid boar sperm during preservation and transportation. The results showed that the addition of appropriate amounts of betaine to boar semen extenders effectively mitigated the adverse effects of road transport and room temperature storage on sperm quality. Specifically, betaine supplementation showed significant protective effects against temperature fluctuation and vibration stress that inevitably occurred during transportation. The increased antioxidant capacity of boar sperm may underlie its beneficial effects. These findings offer a theoretical foundation for the use of betaine in artificial insemination procedures.Abstract Boar semen is commonly used in artificial insemination (AI) for pig breeding, but its quality can be negatively affected by liquid preservation and transportation, leading to reduced fertility rates. Vibration and temperature fluctuations are critical factors that significantly impact semen quality during storage and transportation, influencing the success rate of AI procedures. Betaine, a naturally occurring compound known for its role in maintaining male fertility, demonstrates potential for improving the preservation and transportation of liquid-preserved boar sperm. The present study demonstrated that betaine supplementation in the semen extenders at 0.5 mg/mL had a significant protective effect on boar sperm motility during storage at 17 degrees C for 3 to 5 days. During road transportation, 2.5 mg/mL betaine showed significant protective effects on boar sperm progressive motility, while 0.4 mg/mL betaine notably improved boar sperm mitochondrial activity and antioxidant capacity, and reduced lipid peroxidation damage. Simulation models also demonstrated that betaine supplementation increased the proportion of sperm displaying progressive motility and possessing intact acrosomes, regardless of the storage temperature (17 degrees C or 25 degrees C), and effectively mitigated the damage caused by vibration at a speed of 200 r/min. Overall, supplementing liquid-preserved boar semen extenders with betaine shows promise in mitigating damage to sperm quality during storage and transportation.