Phytogenic Feed Additives in Poultry: Achievements, Prospective and Challenges

Simple Summary Plant secondary metabolites and essential oils also known as phytogenics are biologically active compounds that have recently attracted increased interest as feed additives in poultry production, due to their ability to promote feed efficiency by enhancing the production of digestive secretions and nutrient absorption, reduce pathogenic load in the gut, exert antioxidant properties and decrease the microbial burden on the animal's immune status. However, the mechanisms are far from being fully elucidated. Better understanding the interaction of phytogenics with gastrointestinal function and health as well as other feed ingredients/additives is crucial to design potentially cost-effective blends. Phytogenic feed additives have been largely tested in poultry production with the aim to identify their effects on the gastrointestinal function and health, and their implications on the birds' systemic health and welfare, the production efficiency of flocks, food safety, and environmental impact. These feed additives originating from plants, and consisting of herbs, spices, fruit, and other plant parts, include many different bioactive ingredients. Reviewing published documents about the supplementation of phytogenic feed additives reveals contradictory results regarding their effectiveness in poultry production. This indicates that more effort is still needed to determine the appropriate inclusion levels and fully elucidate their mode of actions. In this frame, this review aimed to sum up the current trends in the use of phytogenic feed additives in poultry with a special focus on their interaction with gut ecosystem, gut function, in vivo oxidative status and immune system as well as other feed additives, especially organic acids.

Automated summary

Plant phytogenic feed additives have been widely tested in poultry production to improve feed efficiency, digestion, and reduce pathogenic load, but their mechanisms of action still need further research. More efforts are needed to determine the proper inclusion levels and fully elucidate their mode of actions.