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The effect of essential oils showing acaricidal activity against the poultry red mite (Dermanyssus gallinae) on aspects of welfare and production of laying hens

Lookup NU author(s): Dr Olivier Sparagano, Dr Gordon Port, Dr Ed Okello, Dr Jonathan Guy


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The poultry red mite (Dermanyssus gallinae) causes severe welfare concerns for laying hens arising from anaemia and disease transmission, and has been identified as an associated risk factor in cannibalistic feather pecking. Previous work suggests that essential oils may offer an alternative to synthetic acaricides to control D. gallinae Such alternatives are needed due to the limitations of synthetic acaricides (eg availability, resistance, environmental concerns and product residues) The aim of the current study was to ensure that selected essential oils have no negative impact on either hen welfare or egg production. To achieve this aim, small groups of laying hens were confined in poultry huts for a period of eight weeks during which time the interior of the huts was sprayed at weekly intervals with one of four different treatments. i) Thyme essential oil at 5x the LC90 level (the concentration of oil previously found to kill 90% of D. gallinae under laboratory conditions) for D. gallinae in 500 ml of water, ii) Pennyroyal essential oil at 5x the LC90 level for D. gallinae in 500 ml of water, in) Solvent-only (huts treated with 500 ml of water), and iv) Pseudo-spray where huts were not treated with any product, but subjected to sham-spraying. The results suggest that pennyroyal essential oil would not be suitable for further development as an acaricide for D. gallinae, since this treatment had to be terminated early in the study period as a result of concerns about the welfare of hens exposed to this oil. Conversely, there were few differences in feather condition, hen weight, feed intake, feeding efficiency, egg production or egg weight between thyme-treated huts and huts that were either pseudo-sprayed or sprayed with solvent-only (water). It is concluded that thyme essential oil is a promising candidate for further development as an acaricide for D gallinae to help safeguard the welfare of laying hens in commercial poultry systems.

Publication metadata

Author(s): George DR, Sparagano OAE, Port G, Okello E, Shiel RS, Guy JH

Publication type: Article

Publication status: Published

Journal: Animal Welfare

Year: 2010

Volume: 19

Issue: 3

Pages: 265-273

Print publication date: 01/08/2010

ISSN (print): 0962-7286

ISSN (electronic):

Publisher: Universities Federation for Animal Welfare