Oral exposure to culture material extract containing fumonisins predisposes swine to the development of pneumonitis caused by Pasteurellamultocida

Abstract

Fumonisin B(1) (FB(1)) is a mycotoxin produced by Fusarium verticillioides and F. proliferatum that commonly occurs in maize. In swine, consumption of contaminated feed induces liver damage and pulmonary edema. Pasteurella multocida is a secondary pathogen, which can generate a respiratory disorder in predisposed pigs. In this study, we examined the effect of oral exposure to fumonisin-containing culture material on lung inflammation caused by P. multocida. Piglets received by gavage a crude extract of fumonisin, 0.5mg FB(1)/kg body weight/day, for 7 days. One day later, the animals were instilled intratracheally with a non toxin producing type A strain of P. multocida and followed up for 13 additional days. Pig weight and cough frequency were measured throughout the experiment. Lung lesions, bronchoalveolar lavage fluid (BALF) cell composition and the expression of inflammatory cytokines were evaluated at the autopsy. Ingestion of fumonisin culture material or infection with P. multocida did not affect weight gain, induced no clinical sign or lung lesion, and only had minimal effect on BALF cell composition. Ingestion of mycotoxin extract increased the expression of IL-8, IL-18 and IFN-gamma mRNA compared with P. multocida infection that increased the expression of TNF-alpha. The combined treatment with fumonisin culture material and P. multocida delayed growth, induced cough, and increased BALF total cells, macrophages and lymphocytes. Lung lesions were significantly enhanced in these animals and consisted of subacute interstitial pneumonia. TNF-alpha, IFN-gamma and IL-18 mRNA expression was also increased. Taken together, our data showed that fumonisin culture material is a predisposing factor to lung inflammation. These results may have implications for humans and animals consuming FB(1) contaminated food or feed.