Results of a study to determine the lethal doses (ld100 and ld50) of s. typhimurium in experiments on laying chickens

In laboratory experiments carried out on 12 day old chickens, the 100% lethal dose (LD100) was established in the amount of 600 million microbial bodies - S. typhimurium. Thus LD50 (killing 50% of chickens) amounted to 400 million Salmonella. The duration of the incubation period in the hyperacute course of experimental salmonellosis of chickens (5 heads) was 6 to 10 hours. Clinical signs and pathological changes characteristic of this disease were not observed. They died 8-12 hours after infection. The incubation period in acute course lasted from 10 hours to 14 hours. In two sick chickens, clinical signs of the disease began to appear after 16 hours, in four more - after 20-24 hours after infection. As a result of bacteriological examination of pathological material (parenchymal organs, tubular bone) of chickens with salmonellosis, cultures of S. typhimurium with all cultural, morphological, biochemical and tinctorial properties were re-isolated