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Loma salmonae ‐associated growth rate suppression in rainbow trout, Oncorhynchus mykiss (Walbaum), occurs during early onset xenoma dissolution as determined by in situ hybridization and immunohistochemistry
Author(s) -
Speare D. J.,
Daley J.,
Markham R. J. F.,
Sheppard J.,
Beaman H. J.,
Sanchez J. G.
Publication year - 1998
Publication title -
journal of fish diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 85
eISSN - 1365-2761
pISSN - 0140-7775
DOI - 10.1046/j.1365-2761.1998.00112.x
Subject(s) - rainbow trout , biology , gill , parasite hosting , in situ hybridization , spore , immunohistochemistry , antigen , monoclonal antibody , andrology , antibody , fish <actinopterygii> , zoology , microbiology and biotechnology , immunology , fishery , biochemistry , gene expression , gene , medicine , world wide web , computer science
Experimental infection of rainbow trout, Oncorhynchus mykiss (Walbaum), juveniles with Loma salmonae at a water temperature of 15 °C yielded detectable parasite DNA within the gills by week 2 post‐exposure (PE) and detectable spore‐wall antigen within developing xenomas by week 3 PE, as determined by in situ hybridization and monoclonal antibody (Mab) based immunohistochemistry, respectively. The microsporidian was most commonly located within endothelial cells of lamellar basal channels. Whereas the onset of xenoma formation appeared to be relatively synchronous, as expected from previous studies, xenoma dissolution followed an unexpected biphasic pattern with peaks at weeks 4 and 9 PE. The onset of significant growth rate suppression, at week 4 PE in exposed fish, was temporally associated with the appearance of gill lesions which, in turn, were centred about sites of premature xenoma dissolution. The latter was determined by the detection of spore‐wall antigen within lesions. Co‐habitant control fish began developing xenomas by week 10, indicating the infective potential of those spores released from the principal fish during early xenoma dissolution. Although infection with L. salmonae significantly affects fish growth rates, the time‐course of this suppression is limited, and as an unexpected finding, growth rate recovery commences prior to the infection’s resolution.