Adding oregano oil to broiler diets can cut Salmonella levels in young birds, potentially providing producers with a natural option to improve flock health and food safety.
A study led by the USDA and Nutrinae has shown that an oregano-based feed additive can reduce the number of broilers carrying Salmonella Enteritidis, a strain associated with food borne illness.
In a two-trial study, day-old chicks were put on either a standard corn–soya starter or the same diet with an oregano oil additive at 300g/tonne. Birds were orally challenged at seven days and sampled at 21 days to assess Salmonella Enteritidis in the ceca and liver.
Researchers found birds fed the oregano diet had fewer positive gut samples, with 40% testing positive compared with 61% in the control group.
The amount of Salmonella in the gut was also far lower — around 3,000 colony-forming units per gram of content, compared with 350,000 in the controls. Liver positives did not differ between groups, suggesting the main effect was in the gut.
The results suggest oregano oil could be a useful pre-harvest tool, helping producers limit Salmonella in flocks before birds reach the processing plant.
How oregano works in poultry diets
Oregano oil is rich in compounds such as carvacrol and thymol, which can damage bacterial cell walls and disrupt energy production.
In this study, published in Poultry Science, a distilled Greek oregano oil with a high carvacrol content was effective on its own – unlike many commercial blends which combine oils with acids or other botanicals.
Birds on the oregano diet also showed stronger immune responses in the gut. Activity of key immune markers was nearly doubled compared with those on a standard diet, suggesting oregano may help stimulate natural defences as well as lowering bacterial load.
With antibiotic growth promoters off the table in many markets and pressure mounting to reduce pathogens on-farm, natural feed additives are gaining traction.
The global animal feed additive market is forecast to more than double by 2030, driven in part by consumer demand for antibiotic-free poultry.
While this work focused on chicks up to three weeks old, the researchers said they plan to track the impact of oregano oil across a full 42-day production cycle, including its effect on performance and food safety outcomes.
Key takeaways
- Oregano feed additive helped young broilers carry less Salmonella in controlled trials.
- Fewer birds tested positive and gut bacterial levels were far lower than in controls.
- Single-ingredient Greek oregano oil used at a practical inclusion rate in starter feed.
- Useful pre-harvest tool for poultry producers aiming to reduce Salmonella and support ABF systems.
- Further work planned over a full grow-out to confirm effects on performance and food safety.
