Essential oils and their use in animal feeds for monogastric animals – Effects on feed quality, gut microbiota, growth performance and food safety: a review

Essential oils (EOs) are important aromatic components of herbs and spices and their biological activities have been known and utilised since ancient times in perfumery, food preservation, flavouring, and medicine. Some of their biological activities include antibacterial, antifungal, anti-oxidant and anti-inflammatory effects amongst others. EOs have received attention in recent years as potential ‘natural’ alternatives for replacing antibiotic growth promoters (AGPs) in animal diets due to their positive impact on growth performance, gut microbiota and welfare. The purpose of this paper is to provide an overview of our own published and unpublished data on the antibacterial, antifungal and insecticidal activity of thymol and cinnamaldehyde (TC blend), and to describe the effects of this specific EO blend on gut microbiota, growth performance and welfare, carcass characteristics and food safety. The possible modes of action of EOs are discussed and areas for future research are proposed.