Essential Oils, Chemical Compounds, and Their Effects on the Gut Microorganisms and Broiler Chicken Production Original paper

What was reviewed?

This review systematically evaluated the role of essential oils (EOs) in improving broiler chickens’ health, gut microbiota, and production outcomes. By analyzing 158 publications, it explored the antimicrobial, antioxidant, and growth-promoting properties of EOs sourced from a wide range of plants such as Origanum, Cymbopogon, Citrus, and Eucalyptus. The focus was on how these plant-derived compounds influence gut microbiota composition, inhibit pathogenic bacteria, and serve as sustainable alternatives to antibiotics in poultry farming. The review also detailed various modes of action, including nutrient absorption enhancement, immune system fortification, and oxidative stress reduction, positioning EOs as a promising tool for sustainable broiler production.

Who was reviewed?

The review focused on studies investigating broiler chickens, specifically those examining the effects of dietary or water supplementation with essential oils. It addressed different microbial communities within the chicken gut, noting common bacterial families such as Lachnospiraceae, Ruminococcaceae, and Veillonellaceae, and pathogens like Escherichia coli, Salmonella spp., and Clostridium perfringens. The review highlighted how EOs influenced these microbiota and the overall health and productivity of broilers.

What were the most important findings?

The review found that essential oils exert significant antimicrobial activity, especially against pathogens like E. coli, Klebsiella pneumoniae, Salmonella spp., and Staphylococcus spp. For example, cinnamaldehyde from cinnamon bark and compounds from Cymbopogon citratus were highly effective in reducing pathogenic bacterial loads, improving intestinal morphology, and promoting a healthier gut environment. Origanum EO not only enhanced gut health but also demonstrated strong antioxidant effects, while Citrus oils showed dual benefits of microbial control and reduction of Eimeria oocysts. Importantly, the use of EOs led to improvements in nutrient absorption through enhanced gut morphology, specifically increasing villi height and enzyme activity, thereby boosting growth performance. These findings emphasize the potential of EOs to rebalance gut microbial populations toward beneficial species like Lactobacillus, reduce pathogenic colonization, and serve as natural growth promoters.

What are the greatest implications of this review?

The review underscores that essential oils can act as sustainable and effective alternatives to antibiotics in poultry production. Their ability to reduce pathogenic bacteria while supporting beneficial gut microbiota is critical in addressing antibiotic resistance issues. The implications extend to safer poultry products for consumers and better environmental outcomes. However, the review also highlighted the need for further research to standardize EO formulations, determine optimal dosages, and assess long-term safety for both animals and humans. The findings encourage poultry producers to consider EOs as part of integrated gut health management strategies that align with global moves toward antibiotic-free animal farming.