The increase of productivity in the poultry industry has been accompanied by various impacts, including emergence of a large variety of pathogens and bacterial resistance. These impacts are in part due to the indiscriminate use of chemotherapeutic agents as a result of management practices in rearing cycles. This review provides a summary of the use of probiotics for prevention of bacterial diseases in poultry, as well as demonstrating the potential role of probiotics in the growth performance and immune response of poultry, safety and wholesomeness of dressed poultry meat evidencing consumer’s protection, with a critical evaluation of results obtained to date.

Avian colibacillosis and salmonellosis are considered to be the major bacterial diseases in the poultry industry world-wide. Colibacillosis and salmonellosis are the most common avian diseases that are communicable to humans. This article provides the vital information on the epidemiology, pathogenesis, diagnosis, control and public health concerns of avian colibacillosis and salmonellosis. A better understanding of the information addressed in this review article will assist the poultry researchers and the poultry industry in continuing to make progress in reducing and eliminating avian colibacillosis and salmonellosis from the poultry flocks, thereby reducing potential hazards to the public health posed by these bacterial diseases.

Bacterio-pathological investigation on 1751 dead chickens during one year period from January to December 2002 at the BRAC Poultry Disease Diagnostic Centre, Gazipur showed that 39.81% (n=697) cases with seven types of different bacteriological diseases of which salmonellosis (n=385), colibacillosis (n=147) and fowl cholera (n=114) were found significantly higher rate of prevalence then staphylococcosis (n=6),  gangrenous dermatitis (n=17), necrotic enteritis (n=24) and infectious coryza (n=4). Accordingly, avian salmonellosis, colibacillosis and pasteurellosis were selected for detailed investigation. Age wise prevalence of avian salmonellosis showed highest infection rate in adult layers (53.25%) in comparison to brooding (14.55%), growing (16.10%) and pullet (16.10%) chickens. The avian colibacillosis was found widely prevalent in all age groups of chickens (9.52 to 36.73%) with specially high prevalence rate in adult layer birds (36.73%). Fowl cholera was recorded in chickens more than two weeks of age with significantly (p < 0.01) highest occurrence in adult chickens. Seasonal influence showed significantly (p < 0.01) highest proportionate prevalence of salmonellosis during summer (48.05%) in comparison to rainy (28.31%) and winter (23.66%) seasons. Colibacillosis was recorded more or less uniformly in all the three seasons of the year with significantly (p < 0.01) higher rate during summer (40.82%) season. Similarly, the prevalence of fowl cholera was also found significantly (p < 0.01) highest during summer (49.12%) in comparison to rainy (26.32%) and winter (24.56%) seasons. The isolated causative agents of avian salmonellosis (Salmonella pullorum), avian colibacillosis (Escherichia coli) and avian pasteurellosis (Pasteurella multocida) were characterized by bacteriological methods which were also subjected to pathogenicity study in 52-day old broiler chickens. Pathogenicity study showed that the incubation period of these three bacterial diseases were recorded as 96 hours and clinical signs appeared on 4th day of inoculation and observed that S. pullorum, E. coli and P.  multocida resulted 100% morbidity in chickens. Key words: Characterization; pathogenicity; salmonellosis; colibacillosis; pasteurellosis; chickens doi: 10.3329/bjvm.v2i1.1926 Bangl. J. Vet. Med. (2004). 2(1) : 01-08