Comparative pathology of heart and liver lesions of broiler chickens that died of ascites, heart failure, and others.

Pathologic changes of 120 dead broilers from a flock of 1000 birds were compared. Macroscopically, the changes were divided into three pathologic types: ascites (retention of ascitic fluid), heart failure (right heart dilation and/or hydropericardium without retention of ascitic fluid), and others (without ascites or heart failure). The rates of ascites, heart failure, and others were 55.8% (67/120), 33.3% (40/120), and 10.8% (13/120), respectively. Histologically, cardiac histologic changes (myocardial degeneration with calcification and epicardial fibrosis) were seen in 40 of 67 (59.7%) ascites cases. Hepatic histologic changes (hepatocytic degeneration/necrosis and hepatic capsule fibrosis) were seen in 64 of 67 (95.5%) ascites cases. Cardiac histologic changes were seen in 24 of 40 heart failure cases (60.0%). Hepatic histologic changes were seen in 36 of 40 (90.0%) heart failure cases. Six of 13 others had hepatic histologic changes, but the remaining seven birds had no significant histologic changes. Ascites and heart failure cases had almost the same percentages of hepatic and cardiac histologic changes. This study indicates that two pathologic types, ascites and heart failure, may be closely related conditions and that hepatic histologic changes may be common and fundamental lesions in the pathogenesis of these pathologic types.