Advances in the Application of Phytogenic Extracts as Antioxidants and Their Potential Mechanisms in Ruminants

Under current breeding conditions, multiple stressors are important challenges facing animal husbandry in achieving animal wellbeing. For many years, the use of antibiotics has been a social concern in the livestock industry. With the implementation of the non-antibiotics policy, there is an urgent need to find relevant technologies and products to replace antibiotics and to solve the problem of disease prevention during animal growth. Phytogenic extracts have the unique advantages of being natural and extensive sources, having a low residue, and being pollution-free and renewable. They can relieve the various stresses, including oxidative stress, on animals and even control their inflammation by regulating the signaling pathways of proinflammatory cytokines, improving animal immunity, and improving the structure of microorganisms in the gastrointestinal tract, thereby becoming the priority choice for improving animal health. In this study, we reviewed the types of antioxidants commonly used in the livestock industry and their applicable effects on ruminants, as well as the recent research progress on their potential mechanisms of action. This review may provide a reference for further research and for the application of other phytogenic extracts and the elucidation of their precise mechanisms of action.