Odor characterization of the poultry red mite (Dermanyssus gallinae) for identification of volatile biomarkers of infestation across multiple commercial laying hen systems.

Infestations by the poultry red mite (PRM) (Dermanyssus gallinae) in laying hen farms can have serious adverse effects on animal health and welfare, and lead to increased egg production costs. Early detection of the PRM is paramount to mitigate its negative impact and for effective pest control. However, current detection methods are labor-intensive and time-consuming. As poultry experts have reported that the presence of PRM is accompanied by a specific scent, opportunities lie in using odor-based detection methods. These methods may offer a fast and reliable alternative for identifying PRM infestations in early stages. To date, however, there is a lack of data on the odor profile of PRM as it has not been characterized. Therefore, in this study, the first step is taken towards determining the composition of the emitted scent of PRM. Samples of PRM and litter were collected across multiple commercial laying hen farms and subjected to TD-GC-MS analysis with subsequent multivariate analysis. Five highly specific volatile organic compound (VOC) targets were identified (1-vinyl-aziridine, 1H-pyrrole, 1-octen-3-one, heptanal and octanal), independent of housing type, feed and farm management. Although the metabolic origin of these VOCs could not be determined in this study, the odor character of several of these VOCs (1-octen-3-one, heptanal and octanal) matches the poultry experts' description. Furthermore, the specificity of all identified VOC targets to PRM samples make them highly interesting potential targets for odor-based detection of PRM infestation.