Experimental Lactococcus garvieae infection in rainbow trout, Oncorhynchus mykiss, Walbaum 1792: a comparative histopathological and immunohistochemical study
WOS: 000334071700007PubMed ID: 23957738The aim of this study was to induce Lactococcus garvieae infection in young and adult fish through different routes [intraperitoneal (IP) and immersion (IM)] and to investigate the pathogenesis and histopathological and immunohistochemical findings comparatively. For this purpose, a total of 180 rainbow trout (90 young, 20 +/- 5g and 90 adult, 80 +/- 10g) obtained from a commercial fish farm were used. The fish were divided into eight groups, four experimental groups (Young-Adult IP groups and Young-Adult IM groups, each contain 30 fish) and four control groups (Young-Adult IP Control groups and Young-Adult IM control groups, each contain 15 fishes). The experimental study was conducted using L.garvieae, and confirmatory identification was performed by PCR. The sequence result of the PCR amplicon of 16S rDNA from isolate L.garvieae LAC1 was determined and deposited in the GenBank database under accession number . Fish in the IP groups were intraperitoneally administered an inoculate containing 10(6)cfumL(-1) bacteria 0.1mL. In the IM groups, fish were kept in inoculated water containing 10(8)cfumL(-1) bacteria for 20min. Mortality as well as clinical and pathological findings was recorded daily, and significant differences in macroscopic and microscopic results were observed between the IP and IM administration groups. All tissue samples were immunohistochemically stained by the avidin-biotin-peroxidase complex and immunofluorescence (IF) methods using polyclonal antibody to detect L.garvieae antigens. In immunoperoxidase staining in the IP groups, positive reactions to bacterial antigens were most commonly seen in the spleen, kidney, heart, liver, peritoneum and swim bladder. In the IM groups, bacterial antigens were most commonly found in the eye, gill, spleen and kidney. In the IF method, the distribution of antigens in tissue and organs was similar to the reactions with immunoperoxidase staining. Finally, in this experimental study, an important correlation was seen between the distribution of L.garvieae antigens and lesions developing in many organ and tissues.Adnan Menderes University Scientific Research Projects UnitAdnan Menderes University [VTF-11001]This study was supported by Adnan Menderes University Scientific Research Projects Unit (Project no: VTF-11001)
