“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.”

“Compared with other sites, analysis of stomach contents of catfish from the Olifants Gorge and the Sabiepoort strongly suggested that consumption of a predominantly fish diet was associated with the development of pansteatitis in these fish. In a farmed population of catfish used as positive control, development of pansteatitis could be ascribed to consumption of rancid fish waste from a trout slaughterhouse. In the Olifants Gorge, alien invasive silver carp, Hypophthalmychthys molitrix (Valenciennes), seasonally migrate upstream out of Lake Massingir to spawn. This schooling species is an obligate phytoplankton feeder with consequent high levels of adipose tissue n-3 polyunsaturated fatty acids. In the Olifants Gorge, at least, this may explain seasonal exposure to levels of polyunsaturated fats in the diets of catfish and crocodiles to which these animals are not adapted.”

Yellow Fat Disease and its overloading of autofluorescent storage material is a dietary dilemma.