The use of plant extracts in animal feeding trials has been considered as a potentialalternative to improve the redox stability of meat. Bioactive compounds from plant extractscan provide the antioxidative mechanisms required to improve animal health and welfareand, to protect meat against oxidation. Pharmacological properties and antioxidant effectshave been associated to the extract of hops and to the extracts of yerba mate. However, theeffects of hops and yerba mate as dietary supplement for animal feeding on the metabolicprofile and the redox stability of meat have not been reported yet. Addition of extract ofmate to a standard maize/soy feed at a level of 0.5, 1.0 or 1.5% to the diet of feedlot forcattle resulted in an increased level of inosine monophosphate, creatine, carnosine and ofconjugated linoleic acid in the fresh meat. The tendency to radical formation in meatslurries as quantified by EPR spin-trapping decreased for increasing mate extract additionto feed especially after storage of the meat indicating an increased resistance to oxidationfor meat. Addition of hops extract at different levels (0, 30 ppm, 60 ppm, 240 ppm) to thediet of broilers demonstrated to have significant effects on the averaged concentration ofpolar metabolites that are of relevance for meat quality. The major metabolic differencesbetween control group (no supplements) and broilers fed different levels of -acids wereachieved using 30 ppm of supplement. As determined by EPR spin-trapping, increasedredox stability was obtained in the samples referring to the animals fed 30 ppm oflupulones and may be related to the highest level of endogenous antioxidants, especiallyanserine, carnosine and NADH. Myosin and actin were recognized as the main targets ofprotein oxidation in meat. Myofibrillar proteins from animals fed with hops -acidsshowed to be less susceptible to oxidation when compared to control group.Mate and hops-acids extracts demonstrated to be promising additives to feedlot for, respectively, cattleand broilers and can improve the oxidative stability, nutritive value, sensory quality, andconsumer acceptance of meat.