Cyanidin improves oocyte maturation and the in vitro production of pig embryos

The objective of this study was to reduce the negative effects of oxidative stress by decreasing the levels of reactive oxygen species (ROS) through supplementation of the major antioxidants present in elderberries: kuromanin and cyanidin. Oocytes (n = 1150) were supplemented with 100 or 200 μM of kuromanin or cyanidin during maturation, and then evaluated for ROS levels or fertilized and evaluated for penetration, polyspermic penetration, male pronucleus formation, and embryonic development. The ROS levels and incidence of polyspermic penetration were lower (P < 0.05) in oocytes supplemented with 100 μM cyanidin when compared with other treatments. Supplementation of 100 μM cyanidin increased (P < 0.05) MPN and blastocyst formation compared with other treatments. However, supplementation of 100 μM kuromanin did not have significant effects on the criteria evaluated, and supplementation of 200 μM kuromanin had significant (P < 0.05) detrimental effects for each criterion. Additional oocytes (n = 1438) were supplemented with 100 μM cyanidin during maturation and evaluated for glutathione, glutathione peroxidase, catalase, and superoxide dismutase activity. Supplementation of 100 μM cyanidin increased (P < 0.05) catalase activity and intracellular GSH levels compared with no supplementation of cyanidin. These results indicate that supplementing cyanidin during maturation reduces oxidative stress by reducing ROS levels and increasing GSH concentrations within the oocyte.