DISTRIBUTION OF INTRAVENOUSLY AND PERORALLY ADMINISTERED AEROMONAS-SALMONICIDA LIPOPOLYSACCHARIDE IN ATLANTIC SALMON, SALMO-SALAR L

The uptake and distribution of Aeromonas salmonicida lipopolysaccharid e (LPS) in Atlantic salmon, Salmo salar L., was investigated. The puri fied LPS molecule was radiolabelled by bromine oxidation and subsequen t sodium borotritide reduction, or fluorescein labelled. After intrave nous injection, high amounts of radiolabelled LPS was found in the spl een, liver, anterior and posterior kidneys at 30 min and 2 h. Twenty f our hours after i.v. administration, the spleen still contained high a mounts of radioactivity, the liver contained increased amounts while t he anterior and posterior kidneys showed reduced contents of radioacti vity compared with the findings 30 min and 2 h after administration. A fter peroral administration, relatively less radioactive LPS accumulat ed in the liver compared with the spleen and kidneys at 0.5, 1, 4 and 24 h. At 24 and 48 h after administration the anterior intestine conta ined high amounts of radioactivity while the posterior intestine conta ined low amounts. Histological examinations of tissue sections reveale d accumulation of fluorescein-labelled LPS in kidney sinusoidal endoth elial cells and macrophages and in splenic ellipsoid sheath cells (mac rophages and reticular cells). Liver endothelial cells also showed acc umulation of FITC-LPS. (C) 1996 Academic Press Limited