Dr Alasdair Nisbet, has been successful in obtaining new research funding from the National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs) to evaluate a new technique that would greatly reduce the number of hens used in the efficacy testing of vaccines against poultry red mites.
Poultry Red Mite (PRM) is a significant economic and welfare concern to the industry worldwide. The mites are blood feeders, often attacking resting birds at night causing pain, irritation, anaemia and a drop in egg production. Demand for novel methods of controlling PRM is high and, typically, the testing of novel control methods uses mites in laboratory-based (“in vitro”) tests initially, followed by field testing using large numbers of hens.
Dr Nisbet and his team at Moredun are working to develop vaccines to control poultry red mite and have used in vitro feeding devices to feed antibodies from immunised hens to small numbers of mites to identify effective vaccine antigens before moving into field trials which use up to 800 hens in each trial. This strategy has 2 major drawbacks: 1) Data from the in vitro feeding devices 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 scientists at Moredun developed an 'on-hen' 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.
Dr Nisbet said, “The specific aim of the proposed study is to further develop the in vivo feeding device into a highly reliable tool for monitoring vaccine- or acaricide-induced effects on mite mortality and and therefore reduce the reliance on large scale, prolonged field trials. We hope that if this project is successful it will lead to the reduction in the numbers of hens used in the efficacy testing of vaccines.”
Dr Vicky Robinson, Chief Executive of the NC3Rs, said: "As always we are funding a diverse range of great projects which will impact on the 3Rs and we will work with the scientists we fund to ensure the 3Rs potential of their science is maximised to benefit as many animals as possible.”
Professor Julie Fitzpatrick, Scientific Director Moredun Research Institute said, “We are delighted that Moredun has been awarded this research grant by NC3Rs and we are committed to the principles of refining, replacing and reducing the use of animals in research. Dr Nisbet and his team are conducting ground breaking work in developing new vaccines to control this devastating disease in hens and this new research project will help them to progress towards this important goal”.