An Improved Method for in Vitro Feeding of Dermanyssus Gallinae (Poultry Red Mite) Using Baudruche Membrane (Goldbeater’s Skin)

Background: Dermanyssus gallinae, or poultry red mite (PRM), is one of the most economically important ectoparasites in laying hens worldwide with infestations leading to both welfare and economic issues. Research into the testing and validation of novel vaccines and systemic acaricides to control PRM initially requires the use of in vitro methodologies before using in vivo assessments. In vitro methods to date have either involved PRM feeding on hen blood through biological membranes such as chick skin, which can be difficult to obtain and variable in quality, or through synthetic membranes that are unsatisfactory due to breakage and lack of natural feeding cues. The use of hen blood in these systems also requires multiple procedures (bleeds) to provide sufficient material for experimental replicates and the potential for using other species, from which larger blood volumes can be withdrawn in a single procedure (e.g. geese), could improve this technique as a refinement in the use of animals in research.

Methods: Using adult female PRM, an initial experiment with an existing in vitro feeding device employing a Parafilm™ M membrane [1] was used to investigate any differences in mite feeding, egg laying and mortality when fed goose or hen blood. Subsequently, any effects on these parameters when PRM were fed through two different membranes; Parafilm™ M and Baudruche membrane, and a combination of these membranes with an overlaid polyester mesh to promote mite attachment, were then tested using goose blood as the food source.

Results: PRM fed equally well on goose or hen blood through a Parafilm™ M membrane and there were no statistically significant differences in mortality of PRM fed with either blood type, although a significant increase (p = 0.03) in eggs laid per fed mite when using goose blood was demonstrated, indicating that goose blood is a satisfactory replacement for hens blood. A 70% increase in PRM feeding was observed when mites were fed on goose blood through a Baudruche membrane when compared to the Parafilm™ M membrane. Addition of an overlaid polyester mesh did not further improve feeding rates on either membrane. A significant increase (p = 0.04) in PRM egg laying was observed in mites fed on goose blood through Baudruche membrane, compared to those fed through Parafilm™ M. A mean of 1.22 eggs per fed mite was obtained using the Baudruche feeding device compared to only 0.87 eggs per fed mite using the Parafilm™ M device when neither had a polyester mesh overlay. It was noted that PRM feeding through Baudruche membrane had fed to repletion when compared to those fed through Parafilm™ M.

Conclusion: The in vitro feeding of poultry red mite can be readily facilitated through the use of goose blood in feeding devices with Baudruche membrane.