Histopathological Profiling of Respiratory Tract Lesions in Chickens

The present study was aimed to characterize histopathological lesions associated with respiratory ailments. Carcasses from a total of 186 broiler flocks and 39 layers flocks showing gross respiratory lesions were examined histopathologically for non-inflammatory and inflammatory lesions. Trachea revealed varying degree of congestion (36.0%) (noninflammatory), acute catarrhal tracheitis (32.1%), acute haemorrhagic tracheitis (11.9%), fibrinous exudative tracheitis (11.0%), and chronic catarrhal tracheitis (9.0%) (inflammatory). Non-inflammatory lesions of lungs included varying degree of congestion (8.7%) and haemorrhage (6.3%). Inflammatory lung lesions were characteristic of bronchopneumonia and included acute catarrhal bronchopneumonia (30.6%), acute sero-fibrinous bronchopneumonia (3.4%), acute haemorrhagic bronchopneumonia (23.1%), acute necrotic bronchopneumonia (8.3%), purulent bronchopneumonia (3.3%), chronic bronchopneumonia (7.6%), acute bronchointerstitial pneumonia (2.6%), chronic bronchointerstitial pneumonia (3.9%) and non-specific granulomatous pneumonia (2.3%). Lesions observed in air sacs included acute airsacculitis (49.3%) and chronic air sacculitis (50.7%). In general the occurrence of various acute lesions was comparable between broilers and layers, whereas occurrence of chronic lesions was comparatively more in layers.