Management or environmental conditions of the current intensive animal production systems may induce acceleration of heart rate, blood flow and a set of metabolic adjustments which, at the end, may promote an imbalance between the production of reactive oxygen species and the animalʹs antioxidant defense mechanisms, resulting in oxidative stress. The oxidative stress in the living animal also is promoted by a high intake of polyunsaturated fatty acids, or by a deficiency of nutrients involved in the antioxidant defense system. In any case, high levels of oxidative stress might influence negatively the animal welfare, and hence the animal performance in intensive production systems. Moreover, the meat quality may also be affected by oxidative stress. Thus, oxidation of lipids is a major cause of deterioration in the meat from fattening and suckling lambs affecting directly meat characteristics such as flavor, color, texture, nutritive value and safety of the product. Lipid oxidation in muscle food is initiated in the living animal, as explained before, but damage to lipids is accentuated, in particular, during handling, processing and storage, thus promoting the reduction of shelf life of meat.