| Abstract: |
This study was carried out for studying the current status of Ornithobacterium rhinotracheale infection in broiler farms at Sharkia governorate.Twenty-three ORT isolates were isolated from 8 out of 72 (11.1%) commercial broiler farms (208 birds) during 2003- 2004 from different localities at Sharkia governorate. Examined birds were ranged from 18 – 42 days-old and suffered from respiratory troublThe incidence of isolation of O.rhinotracheale from different organs were 4.6%, 1.58 %, 1.22%, 0.98%, 0.52% from trachea, lungs, air-sacs, sinus and liver respectively.Obtained colonies on sheep blood agar after 24 hours of incubation appeared as pin-point colonies. After 48 hour, the colonies appeared as pin-headed colonies, circular, opaque, grey to grey white, non pigmented, non hemolytic, convex with smooth surface Biochemical reactions revealed the identity of ORT isolates. It was oxidase, ONPG positive, Catalase negative, highly pleomorphic Gram negative bacteria with variable carbohydrate fermentation pattern.Experimental infection of broiler chickens through aerosol infection with ORT and E.coli, Mycoplasma gallisepticum and the effect of environment in the infection revealed that:• Respiratory signs and lesions produced were differing according to the concomitant infection.• The organism aggravated by E.coli and bad environmental condition, while there was interference with Mycoplasma gallisepticum.• The mortality differed according to the concurrent infection. Hence, concurrent infection with E.coli, Mycoplasma gallisepticum and bad hygiene evoked 25%, 5% and 10% mortality respectively. While no mortality recorded when infection with E.coli, MG and• The reisolation of the organism ranged from 0 to 30% according to the concurrent infection.
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