| Although the Acute Phase Response (APR) is protective, secondary systemic responses triggered by this response cause damage. Down regulation of this cascade may improve animal performance. The purpose of this research was to examine the effects of an APR on broiler performance and body composition, to explore the role of bone in APR modulation in broilers with severe Tibial Dyschondroplasia (TD), and to modify an APR through nutritional manipulation of 25-hydroxycholecalciferol. Injection of 1 mg E. coli LPS/Kg BW increased (P < 0.05) chick liver weight, feed/gain, and mortality; decreased tibia bone calcium, weight, elasticity, and strength (P < 0.05), and increased plasma ionized calcium (P < 0.05). LPS injection increased bronchitis, mycoplasma, and REO titers within 72 hours (P < 0.041). There was an inverse relationship between level of LPS injection, and weight gain, bone strength, and elasticity. Mortality was inversely correlated to liver weight (R 2 = 0.95, P = 0.020) and bone strength (R2 = 0.99, P = 0.010) after an LPS challenge. LPS increased (P < 0.05) chick body temperature and lowered breast yield. Non-injected +TD chicks had larger (P < 0.05) breast than -TD birds. LPS injection increased (P < 0.05) liver weight after 42--48 hours in -TD birds but not in +TD birds. Although +TD chicks had a stronger (P < 0.05) febrile response than -TD birds, mortality of +TD birds was not higher (P > 0.05) than that of -TD birds (26.1% vs. 35.4). +TD birds had lower (P < 0.05) tibia strength, higher fever, and higher Newcastle and bronchitis titers than -TD birds. E. coli LPS challenge increased (P < 0.001) mice plasma IL-1B, IL-6, TNF-alpha, IL-10, IL-4, and IL-12 p40. Supplementation of 25 OH increased (P = 0.002) plasma IL-6 and decreased plasma TNF alpha (P = 0.137) and IL-12 p40 (P = 0.086). Addition of 240 mg 25 OH D3/Kg of feed down regulated (P < 0.001) IL-1B, TNF alpha, and IL-12 p40 in challenged mice microphages. The APR was catabolic, adaptive, and cumulative. Changes in bone homeostasis occurring during an inflammatory response might serve a regulatory function. |
