Chicken-derived IgY recognizes developing and mature stages of Loma salmonae (Microsporidia) in Pacific salmon, Oncorhynchus spp.

A polyclonal IgY preparation, purified from yolk of immunized hens, is shown to be useful for the detection of Loma salmonae in Pacific salmon. Purity of the IgY was confirmed by SDS-PAGE and western blots of yolk protein extracts. Reactivity of the IgY preparation to L. salmonae was determined through indirect-fluorescent antibody tests on purified spores and by immunohistochemistry. Developing xenomas in histological sections of heart and gill tissue of infected chinook salmon (Oncorhynchus tshawytscha) were visualized as early as 4 weeks post-exposure (PE). Non-lethal detection of L. salmonae was obtained by indirect-fluorescent microscopy of acetone-fixed gill smears. The IgY preparation was shown to react with another Loma sp., L. branchialis. In contrast, no reactivity was observed with other microsporidian parasites of fish such as Pseudoloma neurophilia and Glugea anomala. Yolk derived IgY may be useful in the detection of other fish pathogens.