Why did we fund this project?
This award aims to reduce the number of hens needed to test novel control methods for poultry red mite infestation by using an ‘on-hen’ mite feeding device.
Interventions for poultry red mite infestations are tested in field trials typically after assessing the intervention in vitro. Field trials involve a large number of hens (up to 400 per treatment group) being exposed to red mites for prolonged periods. The mites bite the animals and feed on their blood, which causes irritation and anaemia. With NC3Rs funding, Dr Alasdair Nisbet developed an ‘on-hen’ mite feeding device, which allows a precise number of mites to feed on the leg of an animal for a controlled length of time. The mites can then be recovered from the device and analysed for mortality and fecundity. Using this method reduces the number of hens needed to test an intervention from 400 to four per treatment group. The length of time the animals are exposed to the mites is also reduced from a number of weeks to three hours.
Alasdair has previously optimised the use of the ‘on-hen’ device to allow mites at all developmental stages to feed on the hen without impacting on the animal’s behaviour. Alasdair will now give a workshop with researchers from six different research institutions from across the UK and Europe to facilitate the adoptions of the ‘on-hen’ device in their intervention development programmes.
Infestation of hen houses with poultry red mites (PRM) is a major animal welfare and economic problem for the egg industry worldwide. Demand for novel methods of controlling PRM is high and, typically, the testing of novel control methods uses mites in in vitro efficacy assays initially, followed by field testing using up to 800 hens in each trial. This strategy has 2 major drawbacks:
1) Data from the in vitro assays are highly variable and may not accurately reflect field trials;
2) Field trials involve large numbers of birds continually exposed to parasites for prolonged periods.
To address these issues we developed an 'on-hen' in vivo mite feeding device as an alternative to both the in vitro feeding assays and field studies. This system can be used to test vaccine efficacy in longitudinal studies across prolonged experimental periods on small numbers of hens (4 per treatment group, as opposed to 400 per treatment group in field trials) without continuous exposure of the birds to the parasites. We have successfully transferred this technology to a vaccine-development group at University of Castilla-La Mancha, Spain through a COST Action mobility grant and we now wish to hold a 3-day workshop to disseminate this technology with practical demonstrations and discussions around how it intersects with other novel and emerging tools for PRM research to promote its adoption in laboratories across Europe. The proposed participants in the workshop have interests in both refinement and reduction of the use of hens in the development of novel interventions including pesticides, repellents and vaccines and in investigations of the ability of PRM to spread disease. The principal aims of this proposal are to hold a workshop at Moredun Research Institute to demonstrate the construction and use of the device and discuss how this novel technology may be integrated with other emerging technologies (e.g. RNAi) in this field.