Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 11, 1999
Publication Date: N/A
Interpretive Summary: Bacterial infection produces many physiological changes which cause sickness. In certain bacteria this is due to a type of toxic factor called endotoxin present on their cell wall. We studied the effects of one endotoxin on 3 week-old broiler chickens after different times of their injection. The endotoxin produced fever, sickness, loss of body weight, increase in liver weight, and increased the levels of certain white blood cells called heterophils. Birds injected similarly with salt solutions did not show these changes. The levels of certain blood proteins increased in endotoxin-treated birds. It appears that some of these proteins may be responsible for sickness during early time periods after injection and other proteins may be responsible for recovery of the birds at later times.
Technical Abstract: The effects of Salmonella typhimurium lipopolysaccharide (LPS) on the physiology of 3 wk-old broiler chickens were studied at 12 h, 24 h, and 48 h after a single intravenous injection of saline or LPS. LPS elevated cloacal temperature by 3 h after injection, induced a diuretic response, and decreased BW gain. An increase in the relative liver weight was evident in LPS-treated birds at all time intervals, whereas a decrease in the relative weight of bursa of Fabricius was observed only at the 48 h time point. The plasma interleukin-6 (IL-6) and the blood heterophil concentrations were elevated at 12 and 24 h following LPS administration. These changes were not observed in control or 48 h LPS- treated chickens. A decrease in the blood glucose concentration in LPS- treated birds at 12 h was accompanied by an elevation in the blood phosphate level. An increase in total plasma protein concentration was observed only at 24 and 48 h after LPS treatment. Comparative SDS-PAGE analysis of plasma proteins from these birds under non-reducing conditions showed some quantitative differences in four bands of proteins between saline and LPS-treated chickens. A protein corresponding to an approximate MW of 65 kDa increased in LPS-treated chickens, and three other proteins with MW of approximately 39 kDa, 49 kDa, and 56 kDa showed reductions in concentration compared to saline- treated controls. These results show that LPS induces a number of physiological changes that may be responsible for the regulation of the acute phase response in chickens.