The reactive oxygen species (ROS) are unstable and highly reactive molecules capable of transforming other molecules with which they collide. The ROS are generated in large numbers during the oxidative stress, a condition in which molecules are affected such as proteins, carbohydrates, lipids and nucleic acid. This research discussed the main concepts of the free radicals and ROS: main types, their training and how they act on the cellular structures causing significant tissue injury. The main antioxidant defense systems and the influence of the increase in the production of ROS in the respiratory tract of large animals are also discussed, with emphasis on the involvement of ROS in diseases such as pneumonia in ruminants and recurrent obstruction of the airways and pulmonary hemorrhage induced by exercise in horses.
free radicals; reactive oxygen species (ROS); respiratory tract; farm animals
