Sequential Pathogenicity Study of Enteric Bacteria Isolated from Chicken Feeds on Broiler Chickens

Abstract

This study was carried out to investigate the pathogenic potentials of enteric bacteria isolated from chicken feeds sold in Anambra State, Nigeria. A total of 1,536 of different chicken feed samples were collected and screened for the presence of enteric bacteria using pour plate technique. The isolates obtained were characterized and identified. The pathogenic potentials of the isolates on broiler chickens were investigated by challenging the chickens orally using 0.5 ml of the inoculum (10⁸cells/ml). All chickens were kept under complete observation for 4 weeks for pathological signs and symptoms, mortalities and gross morphological lesions of the internal organs. Escherichia coli O157:H7 SS52 (EC), Salmonella ser. Typhimurium U288 (ST), Escherichia coli SEC470 (ES), Salmonella ser. Enteritidis YU39 (SY) and Salmonella ser. Enteritidis FM366 (SE) were isolated from the feed samples. There were significant pathological lesions among the infected chickens, and these decreased significantly (P<0.05) as the age of the chickens increased.The histopathological examination of infected organs revealed congestion, mononuclear infiltration, hemorrhage, necrosis and significant destruction of the organs. The mean plate counts of EC was highest followed by SE, and ST was the least among the plated organs. The isolates showed obvious pathological features among the infected chickens, and these obvious pathological features were pronounced among the chicks mostly the day old chicks.