Pathological Study of Bacterial Infection that Causes Liver Lesions in Chickens

In Bangladesh, poultry disease diagnosis almost entirely depends upon the post mortem examination. The present study was conducted to determine the prevalence of bacterial diseases and liver lesions in chickens based on gross and microscopic lesions. The study was conducted to 377 liver samples collected from chickens from July to December 2017 in the Rajshahi district, Bangladesh. During the collection of samples, clinical signs and gross changes were recorded very carefully. Histomorphological changes were investigated under a light microscope and the lesions were characterized. In this study, the overall prevalence of bacterial diseases was recorded as 14.05% whereas layer chickens (9.54%) and broiler chickens (4.50%). During the study, the prevalence of Salmonellosis was found 8.22% whereas 11.66% in layer chickens and 3.25% in broiler chickens. On the other hand, the prevalence of Colibacillosis was identified 5.83% in chickens in which 3.18% were broiler chickens and 2.65% were layer chickens. In the case of Salmonellosis, grossly livers were friable, congested, enlarged, bronze discoloration with white focal necrosis, egg follicles were congested and hemorrhagic with stalk formation; microscopically livers formed multifocal nodules with coagulation necrosis. Birds with Colibacillosis grossly showed fluid accumulation in the peritoneal cavity of chicks, dark-colored swollen liver and spleen, and perihepatitis. The fatty liver hemorrhagic syndrome showed clotted blood on the liver, congested, enlarged and friable liver, paleness of the body and excess abdominal fat. From the present study, it was evident that considerable numbers of liver lesions were observed in chicken and a systematic study of liver lesions is helpful in making a diagnosis of various poultry diseases.