Levels of bacterial endotoxin in air of animal houses determined with the use of gas chromatography-mass spectrometry and Limulus test.

Air samples were collected on glass fibre filters in 22 animal houses and 3 hay storage barns and examined for the presence of bacterial endotoxin with the Limulus (LAL) test and the gas chromatography-tandem mass spectrometry (GC-MSMS) technique, based on detection of 3-hydroxy fatty acids (3-OH-FAs) as chemical markers of the endotoxin lipopolysaccharide. The median concentrations of airborne endotoxin determined with LAL test in poultry houses, sheep sheds, piggeries, cow barns, and horse stables were respectively 62.49 microg/m3, 26.2 microg/m3, 3.8 microg/m3, 1.65 microg/m3, and 1.14 microg/m3, while those determined with the GC-MSMS technique were respectively 1.06 microg/m3, 7.91 microg/m3, 0.2 microg/m3, 0.31 microg/m3, and 1.42 microg/m3. The median concentrations of airborne endotoxin determined with LAL test and GC-MSMS technique in hay storage barns were much smaller, 0.09 microg/m3 and 0.03 microg/m3, respectively. The concentrations of airborne endotoxin (LPS) detected with GC-MSMS method in the air of sheep sheds were significantly greater than in all other examined facilities, while those detected in hay storage barns were significantly smaller than in all other examined facilities (p<0.05). The concentrations of airborne endotoxin determined with LAL test and GC-MSMS analysis exceeded in most of animal houses examined (91% by each method) the threshold limit value for airborne endotoxin of 0.1 microg/m3 proposed by various authors. A significant correlation (p<0.05) between the concentrations of endotoxin determined with the LAL and GC-MSMS techniques was found in the air samples collected in poultry houses and sheep sheds, but not in other examined facilities. 3-OH FAs with C14-C18 chains were predominant in the air of the facilities under study. A significant correlation (p<0.05) was found between the concentrations of endotoxin determined with LAL test and the amounts of 3-OH FAs with C14-C16 chains. In conclusion, endotoxin in the concentrations detected in this study may present a respiratory hazard to both humans and livestock animals.