Effect of essential oils on Salmonella Heidelberg

Feed withdrawal (8-10 h) pre slaughter reduces the amount of faeces in the bird and gut and therefore, reduces the potential risk of carcasses being contaminated with Salmonella during processing. However, feed withdrawal has been shown to increase the populations of Salmonella in caeca and crops of broilers.

A study on this topic was carried out at various US research institutions. The objectives were to determine the effect of essential oil compared to non-pharmaceutical compounds on the performance, mortality and prevalence of Salmonella Heidelberg (SH) in broilers challenged with SH.

In experiment 1, chicks were randomly assigned to water treatments containing organic acids, essential oils (EO), lactic acid levulinic acid plus sodium dodecyl sulphate, or no added compounds (control). In experiment 2 , chicks were assigned to water treatments containing three concentrations of essential oil and control. In both experiments treatments were administered in drinking water on 0 to 7 and 35 to 42 days.

One-half of the chicks were challenged with SH and placed in pens with unchallenged chicks at day one. Performance and mortality were determined during the 42 day study. Prevalence of SH was determined on drag swabs (0, 14 and 42 days) and in the ceca and crops at 42 days.

Broilers in experiment 1 receiving EO had significantly greater gain and lower mortality than other treatments. Challenged broilers receiving EO and unchallenged broilers receiving EO and lactic acid, had significantly lower SH in crops than other treatments.

In experiment 2, the 0.05% EO administered in drinking water, significantly reduced SH colonisation in crops of challenged birds, significantly lowered the FCR and increased weight gain compared to controls. The EO in drinking water did not significantly reduce SH colonisation in caeca or faecal shedding in broilers.

From these experiments, it can be concluded that essential oils may control SH contamination in broilers when administered in drinking water. Furthermore, essential oils may be an alternative to organic acids in broilers as pre slaughter intervention as SH reduction treatment.

Source: Walid Alali and co-workers, abstracts of the International Poultry Scientific Forum 2013, Atlanta, GA, USA