A pilot study into the chemical and sensorial effect of thyme and pennyroyal essential oil on hens eggs

Summary Previously, it has been shown that thyme and pennyroyal essential oils have potential as acaricides against the poultry red mite Dermanyssus gallinae. The effect of these oils on the occurrence of taint in hens' eggs was investigated using in vitro immersion tests and in vivo methods where poultry huts containing laying hens were sprayed weekly with oil. Analysis of extracts from eggs by gas chromatography mass spectrometry (GCMS) showed that no detectable taint was present in hens' eggs. However, consumer sniff tests, although restricted and only preliminary in nature, showed a significant negative response to the smell of both unbroken and cracked open eggs between those taken from poultry huts treated with pennyroyal essential oil and all other eggs tested. Some essential oils, such as thyme, may be more suitable as an acaracidal product than others, such as pennyroyal, for the use within a commercial poultry system for laying hens.