Endotoxin concentration in poultry houses for laying hens kept in cages or in alternative housing systems

International audience; 1. Endotoxins as components of organic dust may have adverse effects on the respiratory health of workers in poultry buildings. The move towards more welfare-friendly housing systems for layers may increase worker exposure to air contaminants due to the use of litter. 2. The endotoxin concentrations in the inhalable fraction of airborne dust (below 100 µm) from cage and alternative system henhouses (on-floor, free range and aviaries) were compared under both experimental and commercial conditions. 3. The endotoxin concentration was higher in experimental aviaries (median: 565 EU/m3, range: 362-1,491 EU/m3) than in cage housing (98 EU/m3 (51-470)). 4. In field conditions, the endotoxin concentration in the air of 13 alternative henhouses was higher (35 to 3,156 EU/m3) than in cage system buildings (n=8, 78-576 EU/m3). It was correlated to the respirable dust concentration (fraction below 5 µm) and to the temperature inside the henhouse but no seasonal variation was observed. 5. The present study emphasizes that considerable worker exposure to endotoxins may occur in henhouses especially in alternative systems.