RAMA DEVI, VSRILATHA, ChRAO, V.D.PPARIMALA, D.M2016-12-212016-12-212003-10http://krishikosh.egranth.ac.in/handle/1/91927THESESABSTRACT : Liver performs a variety of functions and plays important role in the metabolic processes. The liver lesions were reported in chicken only in relation to certain specific poultry diseases and no detailed systematic studies were done. Hence, the present study was under taken to find out the incidence of various pathological conditions affecting the liver in chicken along with their possible etiological basis. In the present study 1485 birds comprising of 342 broilers and 1143 layers were subjected to post mortem examination that were procured from commercial poultry farms situated in and around Tirupati. Gross and histopathological studies were made and the lesions found were reported. Bacterial isolations were also attempted from suitable liver lesions to know the etiology. Histopathological lesions were observed in 797 birds out of 1485 examined with an incidence of 53.67%. Gross lesions could be observed in 746 birds (50.23%). Various pathological conditions such as circulatory (3.57%), degenerative (19.79%) and inflammatory changes (22.36%) and miscellaneous conditions (7.92%) were recorded. Circulatory disturbances included congestion, which constituted about 4.68% in broilers and 1.57% in layers and haemorrhages observed to an extent of 2.34% in broilers and 0.96% in layers. Out of 1485 birds examined, degenerative changes were observed in 19.79% of birds. The incidence of cloudy swelling was 2.05% in broilers and 1.31% in layers. Hydropic degeneration was found in 3.22% and 1.62% of broilers and layers respectively. Fatty change was observed in 4.10% of broilers and in 2.36% of layers. Necrosis was categorized into focal, centrilobular, periportal and diffuse necrosis. Of these focal necrosis was recorded in 4.10% of broilers and in 5.42% of layers amounting to 5.12% out of total birds. It was the most frequently observed type of necrosis. Centrilobular necrosis was 2.63% in broilers and 4.72% in layers. Periportal necrosis was noticed in 3.22% and 4.29% of broilers and layers respectively. Diffuse necrosis was found in 0.18% of layers. An incidence of 22.36% of inflammatory changes was encountered out of 1485 birds examined. Of these, acute hepatitis was noticed in 4.10% and 5.69% of broilers and layers respectively and sub-acute hepatitis was found in 2.92% of broilers and 5.25% of layers. Chronic hepatitis was recorded in 3.80% and 4.90% of broilers and layers respectively. Perihepatitis was seen in 3.51% and 4.63% of broilers and layers respectively and cholangiohepatitis had an incidence of 2.63% in broilers and 3.50% in layers with an overall percentage of 3.30. Miscellaneous conditions of 7.92% were recorded in the present study out of 1485 birds. Incidence of aflatoxicosis was 2.92% and 3.06% in broilers and layers respectively. Gout was observed in 4.68% of broilers and 3.23% of layers. Fatty liver haemorrhagic syndrome was seen in about 0.58% of broilers, while ascites was found in 2.34% and 0.53% of broilers and layers respectively. Hepatic granuloma was recorded in 0.29% of broilers and 0.09%of layers. Marek’s disease was recorded in of 0.18% of layers. Various microorganisms that were isolated on bacteriological examination from the liver lesions included Clostridium perfringens, E.coli, Pasteurella multocida, Pseudomonas aeruoginosa, and Salmonella gallinarum. Of these, Clostridium perfringens was mainly responsible for cholangiohepatitis and E.coli for perihepatitis. Few suspected feed samples were collected and analyzed for aflatoxin content. Aflatoxin B1 was detected that ranged from 0.01 to 0.5ppm. From the present study, it was evident that considerable number of liver lesions were observed in chicken and a systematic study of liver lesions is helpful in making diagnosis of various poultry diseases.enLIVER LESIONS; CHICKEN; PATHOLOGYThesis