Pansteatitis in rainbow trout Salmo gairdneri Richardson: a clinical and histopathological study


Professor R. J. Roberts, MRCVS, FRSE, Unit of Aquatic Pathobiology, University of Stirling, Stirling, Scotland FK9 4LA.


Abstract. Pansteatitis is a nutritionally mediated condition associated with the feeding of certain types of fish oil or unsaturated fatty acids of fish origin in a diet poor in vitamin E. It occurs regularly in mink, cats, pigs and poultry, all of which are fed on high fish diets, but this is the first description of the condition from cultured fish. The main presenting signs in affected rainbow trout were swimming aberrations, discolouration and high mortality after minimal stress. Gross postmortem features were restricted to changes in the liver and swimbladder but, at the microscopic level, histopathological changes involving inflammatory cellular infiltration of lipid tissue in swimbladder, abdominal and peripancreatic fat and hypodermis, accompanied by myopathic changes, were regularly observed.