Effects of inhalation of dust and endotoxin on respiratory tracts of pigs
Urbain, B.; Mast, J.; Beerens, D.; N'Guyen, T.Q.; Goddeeris, B.; Ansay, M.; Gustin, P.
American Journal of Veterinary Research 60(9): 1055-1060
1999
ISSN/ISBN: 0002-9645 PMID: 10490071 Document Number: 506921
Healthy Belgian Landrace pigs housed in an environmental chamber were exposed for 6 days to feed flour dust (1 to 15 mg/msuperscript 3) and dustborne endotoxins (50 to 2500 ng/msuperscript 3). 29 pigs were used, including controls. Effects were evaluated by measuring albumin concentration, lactate dehydrogenase (LDH) activity, cell composition of nasal lavage (NL) and bronchoalveolar lavage (BAL) fluids and blood, and percentages of CD4+ and CD8+ T lymphocytes in blood and lavage fluids. Dustborne endotoxin was obtained by mixing endotoxins from Escherichia coli (serotype O127:B8) with feed flour before spraying the flour in the environmental chamber. Exposure did not affect cell composition of NL fluid or blood. Total cell counts of BAL fluids were increased in all groups exposed to dust. Macrophage counts were increased in pigs exposed to inhalable dust concentrations as low as 4.4 mg/msuperscript 3, and lymphocyte counts were increased in groups exposed to high dust concentrations. Percentages of CD4+ and CD8+ T lymphocytes in blood and lavage fluids were unchanged. In all dust-exposed groups, albumin content of BAL fluid was increased, whereas LDH activity was unaffected. Macrophage and lymphocyte infiltration and oedema in the bronchi were identified by light microscopy. Effects attributable to E. coli endotoxin exposure were not identified. It is concluded that inhalation of feed flour dust did not affect nasal mucosa but did induce bronchial airway inflammation.