Essential oils in broiler chicken diets as antimicrobial agents: Systematic review

Abstract

The search for alternative ingredient options in the animal diet that have antimicrobial activity is due to many factors, such as pathogens increasing resistance and the presence of antibiotic residues in animal products consumed by humans. Therefore, there is a rising demand for natural additives that do not interfere with animal development or human health. Here, we compare studies on the use of essential oils as antimicrobial agents in broiler chicken diets. First, 90 papers were found using the key words “broilers”, “antimicrobial”, and “essential oils”. The second step was to select the papers according to the scales of Jadad and Medeiros and Stein, where six remaining researchers were selected to describe the antimicrobial activity of essential oils in response to enteric pathogens. Essential oils (EOS) have antimicrobial activity against different pathogens, such as E. coli, S. Enteritidis, S. Heidelberg and C. perfringens, and are considered alternatives to antibiotics used in animal production. The EOs that showed the greatest effectiveness were oregano essential oil (EO), cinnamaldehyde and thymol concentrates; when used together with additives such as sodium butyrate and xylanase, there was better antimicrobial action and improved animal performance. Ginger and carvacrol EOS also demonstrated antimicrobial activities, as did thymol, cinnamaldehyde and eucalyptus EO concentrates, but studies on the specific action of plant species that produce EOS for certain pathogens are still lacking; thus, the topic lacks an ongoing study addressing the addition of EOS in the feed of poultry production.