Abstract |
Two commercial layer chicken flocks that were fed a flax-based diet beginning at 28 weeks of age for the production of omega-3 fatty-acid-enriched eggs experienced increased mortality when the birds reached 37 weeks. The average weekly mortality was 0.34% over a 20-week period, with peak mortality of 0.9% for 1 week. Reduced feed consumption, reduced body weight gain and poor peak production were noticed prior to the onset of increased mortality. A total of 245 birds were necropsied and 78% of these had lesions in the liver and spleen, with 44% of those necropsied having changes consistent with hepatitis- splenomegaly syndrome, with lesions ranging from acute periportal lymphoplasmacytic hepatitis to chronic severe cholangiohepatitis with haemorrhage, vasculitis and amyloidosis. A total of 11% of the birds had lesions typical of fatty liver haemorrhagic syndrome, and 22% had lesions found in both hepatitis- splenomegaly syndrome and fatty liver haemorrhagic syndrome. No significant bacteria or viruses were recovered from samples of the liver/bile or spleen but 11 of 21 bile samples contained avian hepatitis E virus RNA detectable with a reverse transcriptase-polymerase chain reaction assay. Comparative sequence analysis found identities of 82 to 92% and 78 to 80% between the helicase and capsid protein genes, respectively, of the virus detected in this outbreak and those of other avian hepatitis E virus isolates, suggesting extensive genetic heterogeneity in avian hepatitis E viruses in Ontario flocks.
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Authors | A C Agunos, D Yoo, S A Youssef, D Ran, B Binnington, D B Hunter |
Journal | Avian pathology : journal of the W.V.P.A
(Avian Pathol)
Vol. 35
Issue 5
Pg. 404-12
(Oct 2006)
ISSN: 0307-9457 [Print] England |
PMID | 16990151
(Publication Type: Journal Article)
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Topics |
- Animal Feed
- Animal Nutritional Physiological Phenomena
- Animals
- Chickens
(virology)
- Diet
- Disease Outbreaks
(veterinary)
- Fatty Liver
(complications, epidemiology, veterinary, virology)
- Female
- Flax
- Hemorrhage
(complications, epidemiology, veterinary, virology)
- Hepatitis, Viral, Animal
(epidemiology, pathology, virology)
- Hepevirus
(genetics, isolation & purification)
- Ontario
(epidemiology)
- Phylogeny
- Poultry Diseases
(epidemiology, pathology, virology)
- RNA Virus Infections
(epidemiology, veterinary, virology)
- Splenomegaly
(complications, epidemiology, veterinary, virology)
- Syndrome
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