A study of gross, histological and blood biochemical changes in rainbow trout, Oncorhynchus mykiss (Walbaum), with rainbow trout gastroenteritis (RTGE)

J. Del-Pozo, J. F. Turnbull, M. Crumlish, H. W. Ferguson

Research output: Contribution to journalArticlepeer-review

Abstract

The mechanisms behind the pathogenesis of rainbow trout gastroenteritis (RTGE) are still unknown. This study examined the macroscopic and microscopic changes in trout with RTGE (RTGE+), as well as the blood chemistry. A total of 464 rainbow trout were sampled from 11 sites in the UK, comprising 152 RTGE+ fish and 330 random, apparently healthy fish. A case definition for RTGE was assessed by the analysis of its agreement with three laboratory tests: histopathology, packed cell volume and kidney bacteriology. Cluster analysis indicated the presence of three distinct presentations within the population of RTGE+ fish. Cluster A included gross signs associated with moribund RTGE+ fish, and clusters B and C identified gross signs consistent with concurrent diseases, notably furunculosis, enteric redmouth and proliferative kidney disease. The information gained was used to select RTGE+ fish without concurrent disease for the analysis of RTGE pathogenesis with blood biochemistry. This analysis revealed a severe osmotic imbalance and a reduced albumin/globulin ratio as indicatives of selective loss of albumin. These findings are compatible with a protein losing enteropathy.

Original languageEnglish
Pages (from-to)301-310
Number of pages10
JournalJournal of Fish Diseases
Volume33
Issue number4
DOIs
Publication statusPublished - Apr 2010

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