The influence of age and repeated lipopolysaccharide administration on body temperature and the concentration of interleukin-6 and IgM antibodies against lipopolysaccharide in broiler chickens

Abstract

Our objective was to create a standardized and reproducible inflammation model in chickens in order to study the pharmacodynamics of several anti-pyretic and anti-inflammatory drugs. We studied the influence of age and repeated lipopolysaccharide (LPS) administration on body temperature and the correlation of this with concentrations of interleukin-6 and IgM antibodies against LPS in plasma of chickens. Three-week-old and 5-week-old broilers were injected intravenously with LPS from Escherichia coli O127: B8 at a dose of 1 mg/kg. LPS administration was repeated after 2 or 7 days. After the first dose of LPS, the body temperature was initially decreased below normal and then later increased above normal. The second dose of LPS reduced the level of hypothermia and the duration of the febrile phase. Three-week-old birds responded to LPS with a higher maximum body temperature and a greater area under the body temperature versus time curve than 5-week-old chickens (P<0.05). Interleukin-6 reached its highest concentration 3 h after LPS administration and returned to baseline levels after 9 h. A second dose of LPS resulted in a significantly lower peak in interleukin-6. Significant higher levels of antibodies against LPS could be detected 7 days after LPS administration. However, there appeared to be no correlation between the reduced response to LPS and the presence of antibodies.

Brain IL-6- and PG-dependent actions of IL-1β and lipopolysaccharide in avian fever

“…Our first scenario is supported by evidence that 1) innate immune activation triggers the release of IL-6 in birds (9,27), 2) avian thrombocytes, a major component of the innate immune system in birds, upregulate their expression of IL-6 mRNA, as well as the important PG-synthesizing enzyme COX-2, after immune challenge (41), and 3) chickens develop fever following hypothalamic injection of PGE 2 (1). There is convincing evidence that IL-6 and PGE 2 are critically important for febrile mediation in mammals (5,29,35), even though the mechanism by which IL-6 instigates changes in the central nervous system to cause fever in mammals is still controversial.…”

“…For this reason, we chose to measure PGE 2 concentrations in the CSF of Pekin ducks 150 min after LPS treatment, during the rising phase, but before the peak of fever. Previous studies with birds confirmed that systemic LPS treatment initiates an increase in plasma IL-6 concentrations (9,27), and there is evidence that, in pigeons, LPS stimulates peripheral PG synthesis (32).…”

“…Xie et al (54) found, in chickens, that LPS (5 mg/kg) caused fever that peaked 3 h postinjection, while plasma IL-6 concentrations were elevated 12 and 24 h after LPS treatment. In contrast, DeBoever et al (9) found, in chickens, that plasma IL-6 concentrations peaked after 3 h and returned to baseline 9 h after LPS treatment (1 mg/kg), while T b reached a peak after ϳ8 h and resolved 24 h after LPS treatment. Although these data suggest that the time course of plasma IL-6 is not correlated with the time course of fever in chickens, it is known that birds possess well-developed cytokine systems (10,19,47,53) and that avian heterophils synthesize (40,42,43) and secrete (27,40) proinflammatory cytokines into the circulation after an immune challenge.…”

“…From the results of these studies, it is evident that circulating avian immune cells secrete IL-6 upon immune challenge (9,47); yet neither the physiological course of IL-6 in birds nor the relationship between IL-6 and febrile mediation has been elucidated. The results of DeBoever et al (9) and Nakamura et al (27) suggest that peripheral IL-6 contributes to febrile mediation, because the peak concentrations of plasma IL-6 occurred during the rising phase of the fever response in chickens. Our results suggest that circulating IL-6 either crosses the BBB or instigates the de novo synthesis of brain IL-6 to mediate fever in birds.…”

Effect of immune stress on growth performance and energy metabolism in broiler chickens

“…2, 194-203, http://dx.doi.org/10.1080/09540105.2014 bacteria and could stimulate animals to produce innate immune response to change the nutrient metabolism, which would significantly reduce the growth rate of animals. Benson, Calvert, Roura, andKlasing (1993), Fraifeld, Blaicher-Kulick, Degen, andKaplanski (1995), Baert, Duchateau, De Boever, Cherlet, andDe Backer (2005) andDe Boever et al (2008) all observed the increased body temperature after repeated injections of LPS, but did not explain this change from a nutritional point of view.…”