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Pathological and immunological responses associated with differential survival of Chinook salmon following Renibacterium salmoninarum challenge

Diseases of Aquatic Organisms

By:
, , , , and
DOI: 10.3354/dao02214

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Abstract

Chinook salmon Oncorhynchus tshawytscha are highly susceptible to Renibacterium salmoninarum, the causative agent of bacterial kidney disease (BKD). Previously we demonstrated that introduced Chinook salmon from Lake Michigan, Wisconsin (WI), USA, have higher survival following R. salmoninarum challenge relative to the progenitor stock from Green River, Washington, USA. In the present study, we investigated the pathological and immunological responses that are associated with differential survival in the 2 Chinook salmon stocks following intra-peritoneal R. salmoninarum challenge of 2 different cohort years (2003 and 2005). Histological evaluation revealed delayed appearance of severe granulomatous lesions in the kidney and lower overall prevalence of membranous glomerulopathy in the higher surviving WI stock. The higher survival WI stock had a lower bacterial load at 28 d post-infection, as measured by reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR). However, at all other time points, bacterial load levels were similar despite higher mortality in the more susceptible Green River stock, suggesting the possibility that the stocks may differ in their tolerance to infection by the bacterium. Interferon-y, inducible nitric oxide synthase (iNOS), Mx-1, and transferrin gene expression were up-regulated in both stocks following challenge. A trend of higher iNOS gene expression at later time points (≥28 d post-infection) was observed in the lower surviving Green River stock, suggesting the possibility that higher iNOS expression may contribute to greater pathology in that stock.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Pathological and immunological responses associated with differential survival of Chinook salmon following Renibacterium salmoninarum challenge
Series title:
Diseases of Aquatic Organisms
DOI:
10.3354/dao02214
Volume
90
Issue:
1
Year Published:
2010
Language:
English
Publisher:
Inter-Research Science Center
Publisher location:
Oldendorf/Luhe Germany
Contributing office(s):
Western Fisheries Research Center
Description:
10 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Diseases of Aquatic Organisms
Number of Pages:
10
Country:
United States
State:
Michigan
Other Geospatial:
Green River
Additional Online Files(Y/N):
N