title: Changes in the innate immune response of Atlantic salmon, Salmo salar L., exposed to experimental infection with Neoparamoeba sp.
abstract: An experiment was conducted to determine the effect of Neoparamoeba sp. infection on the innate immune responses of Atlantic salmon. Atlantic salmon were experimentally infected with Neoparamoeba sp. and serially sampled 0, 1, 4, 6, 8 and 11 days post-exposure (dpe). Histological analysis of infected fish gill arches identified the presence of characteristic amoebic gill disease lesions as early as 1 dpe with a steady increase in the number of affected gill filaments over time. Immune parameters investigated were anterior kidney phagocyte function (respiratory burst, chemotaxis and phagocytosis) and total plasma protein and lysozyme. In comparison with non-exposed control fish basal respiratory burst responses were suppressed at 8 and 11 dpe, while phorbol myristate acetate-stimulated activity was significantly suppressed at 11 dpe. Variable differences in phagocytic activity and phagocytic rate following infection were identified. There was an increase in the chemotactic response of anterior kidney macrophages isolated from exposed fish relative to control fish at 8 dpe. Total protein and lysozyme levels were not affected by Neoparamoeba sp. exposure.
authors.affiliation: Tasmanian Aquaculture and Fisheries Institute and Aquafin CRC, School of Aquaculture, University of Tasmania, Launceston, Tasmania, Australia. kagross@utas.edu.au
authors.forename: K A
authors.initials: KA
authors.lastname: Gross
authors.forename: M D
authors.initials: MD
authors.lastname: Powell
authors.forename: R
authors.initials: R
authors.lastname: Butler
authors.forename: R N
authors.initials: RN
authors.lastname: Morrison
authors.forename: B F
authors.initials: BF
authors.lastname: Nowak
mesh_terms: D000818:Animals; D017756:Aquaculture; D001798:Blood Proteins; D002633:Chemotaxis / Q000276:immunology; D005393:Fish Diseases / Q000276:immunology* / Q000469:parasitology*; D005880:Gills / Q000473:pathology; D006652:Histological Techniques; D007113:Immunity, Innate / Q000276:immunology*; D016840:Lobosea / Q000276:immunology*; D009113:Muramidase; D010587:Phagocytosis / Q000276:immunology; D011528:Protozoan Infections / Q000276:immunology; D011529:Protozoan Infections, Animal; D016897:Respiratory Burst / Q000276:immunology; D020317:Salmo salar; D013997:Time Factors
chemical_list: D001798:Blood Proteins; D009113:Muramidase