|Carroll, Jeffery - Jeff Carroll|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 7/28/2000
Publication Date: N/A
Technical Abstract: Infectious processes have been modeled experimentally with bacterial lipopolysaccharide (LPS). However, febrile, anorectic, and neuroendocrine responses to LPS are limited to a few hours post-challenge. In contrast, in porcine models of bacterial infection, these responses expand into several days post-infection, suggesting that LPS challenge models have limitations for modeling bona fide infectious processes. The current stud was designed to assess changes in systemic cytokines in pigs in response to Actinobacillus pleuropneumoniae (APP) infection. Weaned pigs were housed in individual pens with free access to feed and water. Jugular catheters were inserted nonsurgically into all pigs about 7 d prior to challenge. At infection, pigs were given 5 X 10**8 CFU APP intranasally (n=3), or a similar intranasal volume of sterile media (n=3). Serum was collected at frequent intervals from -12 to 24 h relative to infection, and later assayed for interleukin 1beta (IL1), tumor necrosis factor alpha (TNF), an interferon gamma (IFN) utilizing porcine specific ELISAs for each cytokine. Infection with APP failed to alter profiles of IL1 (P>.3), TNF (P>.5) and IFN (p>.5) in the 24 h post-infection. Concentrations of IL1 generally averaged between 30-70 pg/mL and TNF between 90-160 pg/mL for both treatments. All concentrations of IFN were below 20 pg/mL. We reported previously this APP model evoked a prolonged surge in serum cortisol, disrupted feed intake, and resulted in unmistakable clinical signs of disease in infected pigs. Thus, we conclude that this bacterial pneumonia model is not associated with changes in systemic IL1, TNF and IFN in weaned pigs.