Effects of inhalation of dust and endotoxin on respiratory tracts of pigs.
OBJECTIVE
To assess the effects of inhalation of feed flour dust and dustborne endotoxin on respiratory tracts of pigs.


METHODS
29 healthy Belgian Landrace pigs.


METHODS
Pigs housed in an environmental chamber were exposed for 6 days to feed flour dust (1 to 15 mg/m3) and dustborne endotoxins (50 to 2,500 ng/m3). 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.


RESULTS
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/m3, 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 edema in the bronchi were identified by light microscopy. Effects attributable to E. coli endotoxin exposure were not identified.


CONCLUSIONS
Inhalation of feed flour dust did not affect nasal mucosa but did induce bronchial airway inflammation. Dustborne endotoxins did not have effects attributable to endotoxin alone.
Urbain
B
B
Département de Pharmacologie-Pharmacothérapie-Toxicologie, Faculté de Médecine Vétérinaire, Université de Liège, Belgium.
Mast
J
J
Beerens
D
D
N'Guyen
T Q
TQ
Goddeeris
B
B
Ansay
M
M
Gustin
P
P
D000418:Albumins / Q000032:analysis; D000821:Animal Feed; D000818:Animals; D000911:Antibodies, Monoclonal; D018893:Bronchoalveolar Lavage / Q000662:veterinary; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D004391:Dust / Q000009:adverse effects*; D004731:Endotoxins / Q000009:adverse effects / Q000276:immunology*; D004926:Escherichia coli / Q000472:pathogenicity; D005434:Flow Cytometry / Q000662:veterinary; D005455:Fluorescent Antibody Technique / Q000662:veterinary; D019570:Inhalation Exposure / Q000009:adverse effects*; D007770:L-Lactate Dehydrogenase / Q000097:blood; D007958:Leukocyte Count / Q000662:veterinary; D008168:Lung / Q000473:pathology; D017817:Nasal Lavage Fluid / Q000276:immunology; D011863:Radioimmunoassay / Q000662:veterinary; D011897:Random Allocation; D012140:Respiratory Tract Diseases / Q000209:etiology / Q000276:immunology / Q000662:veterinary*; D013552:Swine; D013553:Swine Diseases / Q000209:etiology* / Q000276:immunology / Q000517:prevention & control
D000418:Albumins; D000911:Antibodies, Monoclonal; D004391:Dust; D004731:Endotoxins; D007770:L-Lactate Dehydrogenase