Bath exposure of Atlantic halibut (Hippoglossus hippoglossus L.) yolk sac larvae to bacterial lipopolysaccharide (LPS): absorption and distribution of the LPS and effect on fish survival.

摘要

When exposed to radiolabelled lipopolysaccharide (LPS) from Aeromonas salmonicida subsp. salmonicida (6.25, 12.5, 25, 50 or 100μg [3H]LPS/ml), Atlantic halibut larvae absorbed LPS after 5 days exposure in a time and concentration dependent manner.Absorption was comparatively less in larvae exposed to 50 and 100μg/ml than in groups exposed to the other 3 concentration at 10 and 15 days. Fluorescence microscopy of sections from larvae exposed to FITC-LPS (25, 50 or 100μg/ml) for 5, 10 or 15 daysdetected fluorescence in intestinal epithelial cells, connective tissue cells adjacent to the intestines, in cells between the integumental layer and yolk sac, and in some integument epithelial cells. Immunohistochemistry showed that LPS was confined tointestinal epithelial cells, lumen of excretory duct and in many cells in the epidermal layer. Larvae exposed to 12.5, 25, 50 and 100μg/ml LPS survived for significantly longer after exposure to 50 and 100μg/ml from day 20 and throughout the yolk sac period compared with control larvae.