Airborne Particulate Matter and Culturable Bacteria Reduction from Spraying Slightly Acidic Electrolyzed Water in an Experimental Aviary Laying-Hen Housing Chamber

Abstract

<p>Compared to conventional cage laying-hen houses, aviary hen houses generally have much higher concentrations of airborne dust and bacteria due to generation of bioaerosols by the hens’ access to and activities on the litter floor. Hence, reducing these airborne agents is important to safeguard the health of the animals and workers in such housing systems. Spraying slightly acidic electrolyzed water (SAEW) is a novel approach to reducing airborne culturable bacteria (CB) and particulate matter (PM) levels in hen houses. The objective of this study was to evaluate the efficacy of reducing airborne CB and PM in an experimental aviary chamber by periodic spraying of SAEW (Trt), as compared to no spraying (Ctrl_ns) or spraying of tap water (Ctrl_w). The hens were provided 16 h light and 8 h dark (lights on at 6:00 h and off at 22:00 h) and were given access to the litter floor from 12:00 h to 22:00 h. The Trt regimen sprayed SAEW at 14:00 h for 15 min at a dosage of 80 mL m^-2; the Ctrl_ns regimen had no spraying; and the Ctrl_w regimen sprayed tap water following the same procedure as with Trt. Concentrations of airborne CB and PM in six aerodynamic size ranges (0.65-1.1, 1.1-2.1, 2.1-3.3, 3.3-4.7, 4.7-7.1, and >7.1 μm) were measured at 1.5 m above the floor in the center of the room during the periods of 13:45-14:00 h and 14:45-15:00 h. Compared to Ctrl_ns, spraying SAEW significantly reduced airborne CB (>2.1 μm) by up to 49% ±10% (p < 0.05), while Ctrl_w did not show a reduction effect. No significant difference was found between Trt and Ctrl_w in reducing airborne PM, although both reduced or tended to suppress PM >7.1 μm in size. The results show that spraying SAEW can inactivate airborne CB attached to PM. Thus, this is a promising technique for alleviating the adverse health impacts of bioaerosols in aviary laying-hen housing systems.</p>