CHRONIC EXPOSURE OF PIGS TO AIRBORNE DUST AND ENDOTOXINS IN AN ENVIRONMENTAL CHAMBER - TECHNICAL NOTE

A new experimental setup was developed to expose pigs to dust and airb orne endotoxins in an environmental chamber, at levels liable to be en countered in pig farm buildings. The following parameters were evaluat ed in a chamber containing two pigs of 10 kg body-weight: inhalable an d respirable dust gravimetric concentrations were measured using area samplers and expressed as mg/m(3). The respirable dust concentration w as also measured using a 'TM digital mu P respirable dust-measuring in strument', which has been shown to give similar results to the gravime tric method. The endotoxin concentration was evaluated using the Limul us-assay and expressed as ng/m(3) of air containing the inhalable or r espirable dust or as ng/mg of inhalable and respirable dust. Feed flou r dust was introduced into the chamber to obtain different concentrati ons of inhalable and respirable dust ranging from 3.62 to 76.66 mg/m(3 ) and from 0.24 to 1.40 mg/m(3), respectively. The endotoxin concentra tion was modulated by mixing the feed flour with Escherichia cell endo toxins before blowing ii into the chamber. The endotoxin concentration s in the air containing inhalable or respirable dust ranged from 28.9 to 270.0 ng/m(3) and from 2.22 to 36.38 ng/m(3), respectively, dependi ng on the amount of endotoxins added to the dust. Data were also obtai ned in a piggery. The experimental setup detailed in this paper could be used to study the significance of air contaminants in the developme nt of pig respiratory diseases.