Essential oils benefit broiler gut health

Antibiotics in sub-therapeutic doses have been used in animal diets, including poultry diets, to enhance animal performance. Its continuous use however also led to negative effects as disturbed gastrointestinal health and increased antimicrobial resistance, which is a potential threat to human health as well. Reasons why its intensive use has been banned in many countries. Since then, the search has been on to find suitable alternative supplements.

Plant essential oils

Alternatives to antibiotics applied in broiler production include plant essential oils, probiotics, and antimicrobial peptides. Plant essential oils with their bioactive ingredients that express antimicrobial, antioxidant, and anti-inflammatory activities such as oligosaccharides, polyphenols, and saponins, are considered good alternatives. Gastrointestinal health and animal growth are determined by gastrointestinal bacteria, therefore the interaction of alternative products with intestinal bacteria affect gut morphology, nutrient absorption, and immune responses of the host.

Combining eucalyptus oil and carvacrol

Eucalyptus oil and carvacrol are plant oils used in broiler production and known for their effect on the occurrence of necrotic enteritis. Studies with cinnamyl aldehyde and capsaicin have shown anti-inflammatory functions. The effects of a combination of these essential oils on broiler production have not been studied, therefore a combination of these four essential oils was used to investigate their effects on gastrointestinal health by regulating the intestinal probiotic bacteria and improving the intestinal epithelium, and growth performance of broilers.

Experimental set-up

720 male broilers each were divided in three groups: control, Aureomycin supplementation, and combined plant oils supplementation, during a 42 days feeding trial. Growth performances, carcass performances, intestinal sections, and caecal microbiota were investigated. No significant differences were found for feed conversion ratio, feed intake, bodyweight gain, culling rate and carcass performance.

Effect on caecal microbiota

For the aspects of intestinal section, caecal microbiota results demonstrated that bacterial diversity and some representative probiotic bacteria were significantly increased in numbers after supplementation of the combined plant oils mixture. This supplementation did not make significant effects on intestinal wall thickness, villus heights, crypt depths, and the ratio of villus heights/crypt depths compared with the control or antibiotic treatments. The combination of essential oils promoted intestinal health through improving gut bacterial diversity and probiotic bacteria, which results indicate that the combination of essential oils can be applied as an alternative product to antibiotics.