Elevated dietary selenium rescues mitochondrial capacity impairment induced by decreased vitamin E intake in young exercising horses.

Mitochondria, colloquially referred to as the powerhouses of the cell, are essential for sustained energy production, which is particularly important for athletic performance. During exercise, reactive oxygen species (ROS) are produced as a normal byproduct of muscle contraction. ROS act as critical signaling molecules and are essential to stimulate adaptation to exercise and other stressors. However, if excess ROS are produced and not sequestered by antioxidants, they may damage cellular components such as lipids, proteins, and DNA. Selenium (Se) and vitamin E (vitE) are two primary dietary antioxidants that aid in quenching excess ROS. To evaluate the impact of Se and vitE on mitochondria, three diets differing in Se and vitE levels were provided to lightly exercising young horses for 12 wk. Skeletal muscle mitochondrial capacity was negatively impacted by the reduction of dietary vitE, which was rescued with elevated dietary Se. The results highlight the importance of determining optimal levels of minerals and vitamins in performance horse diets to ensure proper energy production during exercise.