The acute phase response in Japanese quail (Coturnix coturnix japonica)

Experiments were conducted to determine the effect of injection of lipopolysaccharide (LPS, from S. typhimurium) or muramyl dipeptide (MDP, N-acetylmuramyl-L-ala-isoglutamine) in Japanese quail. Doses of MDP between 0.3 and 10 mg/kg body wt. had no effect on body temperature. In contrast, doses of 1.0-22.5 mg LPS/kg body wt. caused significant increases in body temperature. None of the doses of LPS or MDP resulted in mortality. The febrile response to LPS was diminished following a second injection 48 h after the first, and was absent following a third injection. Plasma zinc, an indicator of the acute phase response, was significantly reduced by either LPS or MDP after the first injection (P < 0.001), but not after the second or third injection. Splenic interleukin 1-beta (IL-1 beta) mRNA expression was increased after the first and last injection of LPS (P < 0.001), but only after the first injection of MDP (P < 0.005). Hepatic IL-1 beta mRNA expression was increased after the first, but not the third injection of LPS (P < 0.001), while MDP had no effect. These data indicate that Japanese quail are less sensitive to MDP than LPS, and that quail demonstrate tolerance to LPS following repeated injections. (C) 2001 Elsevier Science Inc. All rights reserved.