Synergistic action of E. coli endotoxin and Pasteurella multocida type A for the induction of bronchopneumonia in pigs

No significant changes were observed in Pma-treated or in control animals. Each LPS doses induced DWG reduction while the higher generated a severe subacute interstitial pneumonia causing hyperthermia and an increase in Penh. The combination of the lower LPS doses with Pma produced an asymptomatic bronchopneumonia leading to DWG reduction, rise in Penh and an increase in BALF macrophages and neutrophils. With 400 μg/kg LPS, Pma worsened the inflammatory process as illustrated by cough, hyperthermia, major DWG reduction and by a greater Penh response. Lung lesions consisted of severe exudative bronchopneumonia. We concluded that LPS may negatively influence growth, predispose to persisting lung inflammatory process and promote Pma infection depending on the dose previously administered.