Impact of the mites Dermanyssus gallinae and Tyrophagus putrescentiae on production and health of laying hens

Mites are considered a threat to the commercial poultry industry due to their direct and indirect pathogenic effects. Dermanyssus gallinae is among the mite species that endanger production, as it is hematophagous and poses a serious sanitary risk. Recently, Tyrophagus putrescentiae has also drawn attention as a potential pest in the poultry industry, and its attacks have been related to clinical symptoms such as cutaneous eruptions and bird restlessness. Considering the potential economic, sanitary, and productive losses both species represent to the laying-hen industry, the aim of the present study was to evaluate the influence of D. gallinae and T. putrescentiae on the health and productivity of commercial laying hens by carrying out infestation experiments and by monitoring laying hens for a period of 60 days. Tyrophagus putrescentiae and D. gallinae affected egg quality and zootechnical parameters in laying hens. Hens infested by T. putrescentiae had behavioral changes, weight loss, stress symptoms, and decreased egg laying and quality, as well as diarrhea, gradual feather loss, and itching. Hens infested by D. gallinae also had weight loss, behavioral changes, and stress symptoms, leading to decreased laying and egg quality. The present study proposes an experimental model to understand the impacts caused by T. putrescentiae and D. gallinae on commercial laying production and egg quality parameters.