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The objective of this study was to identify the causative agents of hepatitis observed in broiler chickens at processing. Livers of chickens from 16 broiler farms in Saskatchewan with gross lesions of hepatitis were collected at processing. In addition to routine bacterial isolation and histopathological examination, serologic studies for infectious bursal disease virus (IBDV) and Chicken anaemia virus (CAV), calculation of the ratio of the weight of the bursa of Fabricius (BF) to body weight (BBW), and histopathological examination of the BF were done. Of the 264 livers with gross lesions, 83% had multifocal to coalescing necrotizing hepatitis, 16% had perihepatitis, and 1% had hemorrhages. No definitive causative microorganisms were isolated from the hepatic lesions; however, no significant bacterial isolations were made. Bursal atrophy, low BBW ratio, and high titer of antibody against IBDV each correlated with the rate of total condemnations (P = 0.0188, P = 0.0001, and P = 0.0073, respectively). Nucleotide sequencing of IBDV isolated from the BF identified the variant strains Delaware-E and 586. Condemnation because of hepatic lesions was correlated with titer of antibody against IBDV and BBW (P = 0.016 and P = 0.027). The results of this study demonstrate that hepatic lesions in Saskatchewan chickens are not currently caused by a primary bacterial pathogen but are associated with indicators of immunosuppression that is likely due to variant IBDV.L’objectif de la présente étude était d’identifier les agents causals de l’hépatite observée chez des poulets à griller au moment de la transformation. Les foies de poulets provenant de 16 fermes de poulets à griller en Saskatchewan avec des lésions macroscopiques d’hépatite furent prélevés. En plus de l’isolement bactérien de routine et de l’examen histopathologique, on effectua des analyses sérologiques pour le virus de la bursite infectieuse aviaire (VBIA) et le virus de l’anémie du poulet (VAP), le calcul du ratio du poids de la bourse de Fabricius (BF) sur le poids corporel (BPC), et l’examen histopathologique de la BF. Sur les 264 foies ayant des lésions macroscopiques, 83 % avaient des lésions multifocales à coalescentes d’hépatite nécrosante, 16 % de la péri-hépatite et 1 % des hémorragies. Aucun agent causal définitif ne fut isolé des lésions hépatiques; toutefois, aucun agent bactérien significatif ne fut isolé. Une atrophie de la bourse, un faible ratio BPC, et un titre élevé d’anticorps dirigé contre VBIA corrélaient tous avec le taux de condamnation totale ( |
