An acute inflammatory response alters bone homeostasis, body composition, and the humoral immune response of broiler chickens.

To quantify the effects of an acute phase response in broilers, chicks were injected with 1 mg/kg Escherichia coli lipopolysaccharide (LPS) at 15 and 23 d. Lipopolysaccharide injection increased feed/gain (P = 0.03), increased liver weight (P = 0.09), and decreased tibia calcium (P = 0.05) and breaking strength (P < 0.04) by d 28. In a second experiment, 3 d postinjection of chicks at d 31, LPS decreased BW (P < 0.01), breast weight (P = 0.08), and tibia breaking strength (P = 0.05), and increased liver weight (P < 0.01), mortality (P = 0.05), and titers to bronchitis and Mycoplasma gallisepticum that were induced by vaccination at hatch or by field exposure, respectively (P = 0.04). For experiment 3, chicks were challenged with LPS at 23d and 27d. Lipopolysaccharide-injected chicks had decreased BW (P = 0.06), feed consumption (P = 0.05), tibia weight (P< 0.01), and breaking strength (P < 0.01), and increased feed/gain (P < 0.01), liver weight (P < 0.01), and plasma ionized calcium level (P = 0.08). For experiment 4, chicks were injected with 0, 0.33, 0.66, 1.00, or 4.25 mg of LPS/kg of BW. There was an inverse relationship between LPS level and BW or bone breaking strength. Experiment 5 compared 4 broiler strains. Strain x LPS interactions were found for bone breaking strength (P = 0.01). Mortality before LPS challenge was inversely correlated to liver weight (r2 = 0.95, P = 0.02) and bone breaking strength (r2 = 0.99, P = 0.01) only after an LPS challenge.