ACUTE-PHASE PROTEIN RESPONSE, FOOD-INTAKE, LIVEWEIGHT CHANGE AND LESIONS FOLLOWING INTRATHORACIC INJECTION OF YEAST IN SHEEP

Acute phase protein concentrations in blood, food intake and liveweigh t changes were compared in 10 sheep given intrathoracic-injections of yeast and 10 control sheep over a period of 61 days. The yeast injecti ons caused acute pleuritis and limited necrotising lung lesions which progressed to fibrous pleural adhesions and walled-off abscesses. The responses of ceruloplasmin, fibrinogen and haptoglobin were closely co rrelated (r = 0.87 to 0.91) in the yeast-injected sheep with peaks on days 5 or 7 after treatment (4, 4.6 and over 130 times control, respec tively). Albumin concentration fell to a nadir of 89 per cent of contr ol on day 12 after treatment. Depression of food intake was temporally related to the 'positive' acute phase protein responses with a nadir on day 5 after treatment (30 per cent of control). Liveweight showed a pronounced fall to five days after treatment and thereafter remained depressed relative to the controls for most of the experimental period . The data suggest that the 'positive' acute phase proteins may be use ful indicators of production losses due to inflammatory diseases in sh eep.