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Abstract

Salmonella enterica can be considered as one of the most important causes of foodpoisoning with poultry thought to be the main source. Although S. Typhimurium, S. Enteritidis and the vast majority of other Salmonella serovars generally produce little systemic disease in adult chickens, they are able to colonize the alimentary tract of poultry. The two caeca are the main sites of the colonization of Salmonellae in chickens, and the bacteria can be easily harvested from the caeca for analysis. Bacterial proteins analyses utilizing SDS-PAGE showed differences between in vitro and in vivo that out of about 40 protein bands of in vitro preparation only a few (3-5) bands can be visualized from in vivo preparations. We suggested that some avian proteases might be responsible. Accordingly, and to investigate the hypothesis that an inactivated vaccine harvested from chickens is thought to be more protective than bacteria grown in broth culture, the immunogenicity of inactivated vaccines, either proteins or formalin killed bacteria (S. Enteritidis) harvested from chicken intestine and those from broth culture (in vitro), were compared using bacterial proteins or formalin killed bacteria as an orally inoculated vaccine candidate in chicken. The results demonstrated that sonicated proteins extracts in general have a stronger effect as vaccines against S. Enteritidis colonization in chickens than formalin killed bacteria. In contrast, the in vitro sonicated proteins obtained from a nutrient broth culture had a much better protective vaccine effect than the in vivo sonicated proteins preparations harvested from bacteria grown in chickens. IntroductionMany bacterial pathogens such as Clostridium, Staphylococcus, Campylobacter and many other bacterial strains are capable of causing food-poisoning, and Salmonella enterica can be considered as one of the most important causes with poultry thought to be the main source. Although S. Typhimurium, S. Enteritidis and the vast majority of other Salmonella serovars generally produce little systemic disease in adult chickens, they are able to colonize the alimentary tract of poultry, resulting in contamination of poultry carcasses and entry into the human food chain. However, there is a great demand to control food-poisoning salmonellosis at both breeder and layer levels at the national and global level in order to produce Salmonelle-free poultry products, due to the current correlation between S. Enteritidis PT4 and poultry products. Salmonellosis costs the European Union a minimum of 500-900 million Euros annually. Salmonellosis in food animals is a major target for reduction of human infection by the European Union. Legislation has been introduced to monitor the most important Salmonellae serovars. The major Salmonellae serovars of public health consequence are S. Typhimurium and S. Enteritidis (causing 15% and 60% respectively of all cases in Europe in 2002).Elazomi and Dhawi studied newly-hatched chickens infected with S. Enteritidis. They analyzed proteins of S. Enteritidis...