Application of plant essential oils in pig diets

Abstract This chapter summarizes current research on the efficacy, possible mechanisms, and feasibility in the application of phytogenic compounds as feed additives in pig diets. Phytogenic compounds are defined as plant-derived natural bioactive compounds with positive effects on animal growth and health, and are often applied to essential oils (EOs), botanicals, and herbal extracts. Some phytogenic compounds have a variety of functions, including antimicrobial, antioxidative, antiinflammatory, and immunoregulatory effects. The commercial phytochemicals applied in pig production including oregano EO and cinnamaldeyde have been shown to improve growth performance and intestinal health in weaned piglets, reproductive performance in sows, and semen quality in boars. Therefore, several phytochemicals are regarded as potential alternatives to antibiotics in pig production. However, there has been a lack of consistency in laboratory results due to the varied composition of products, dosages, and duration of treatment. The integration of multi-omics information may help to understand the mechanisms underlying phytogenic compounds' functions and subsequently guide their effective use.