Isolation and Identification of Bacterial Agents Associated With Respiratory Infections In Broiler Chicken with Special Reference to Ornithobacterium Rhinotracheale
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Date
2007
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Publisher
TANUVAS, Chennai
Abstract
A study was undertaken on bacterial agents associated with respiratory
infections in broiler chicken with special reference to Ornithobacterium
rhinotracheale.
A total of 104 samples such as trachea, lungs, air sacs, infraorbital sinus
exudate swab, heart blood swab and liver samples were collected at necropsy from
recently dead and ailing birds showing respiratory disease symptoms from 23
commercially reared broiler farms in and round Erode and Namakkal towns of
Tamil Nadu state. In total 25 (51.0 per cent), 3 (6.1 per cent), 8 (16.3 per cent), 8
(16.3 per cent), 3 (6.1 per cent), 2 (4.0 per cent), isolates were identified as E. coli,
O. rhinotracheale, P. haemolytica, H. paragallinarum, Staphylococcus aureus and
Streptococcus spp. respectively. The E. coli was isolated in pure culture from
fifteen cases, from one case with O. rhinotracheale, from eight cases with
P. haemolytica, and one case with H. paragallinarum. Ornithobacterium
rhinotracheale was recovered in pure culture from two cases, and one isolate with
E. coli. H. paragallinarum was isolated purely from six cases, from one case with
E. coli, from one case with Staphylococcus aureus. Staphylococcus aureus was
isolated in pure culture from two cases, and one case with H. paragallinarum.
Streptococcus spp. was purely isolated from two cases.
The three bacterial isolates identified as Ornithobacterium rhinotracheale
by colonial morphology and biochemical tests were analyzed further by polymerase
chain reaction analysis.
Biochemical reactions of all the three isolates revealed no growth on
MacConkey’s agar and no reaction on triple sugar iron agar. All the isolates were
positive for oxidase, acetyl methyl carbinol production, β-galactosidase (ONPG) and
urease activity. The isolates were negative for catalase, citrate utilization, indole,
methyl red reaction, nitrate reduction, phenylalanine deamination and gelatin
liquefication. All the isolates were positive for arginine dehydrolase and negative for
lysine and ornithine decarboxylases. All the three isolates produced no gas upon
fermentation of any carbohydrate.
In polymerase chain reaction analysis, all the three isolates produced the
predicted size of 784 bp amplicons.
Standardized serum plate agglutination test (SPAT) for rapid serologic
detection of birds exposed to O. rhinotracheale, was developed. Total of 147 blood
samples were collected from broilers (86) and layers (61), with the history of respiratory
disorders and used for SPAT. Of the 86 serum samples obtained from broiler
chickens, 17 (19.77 per cent) were positive for antibodies to O. rhinotracheale, which
represented 4 of the 15 (26.67 per cent) flocks examined. Of the 61 serum samples
obtained from layer chickens, 21(34.43 per cent) were positive for antibodies to O.
rhinotracheale, which represented 4 of the 16 (25 per cent) flocks examined.
The results of SPAT indicated that the prevalence of O. rhinotracheale
antibodies is high in the layer chicken compared to broiler population. This SPAT for
detecting O. rhinotracheale antibodies could be a valuable technique in the mass
screening of flocks for O. rhinotracheale infections in poultry population.
Gross and histopathological studies evinced that O. rhinotracheale could
cause pathological changes on the tissues of O. rhinotracheale infected birds
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Keywords
Veterinary Science, Veterinary Microbiology