Morphological effects of rapeseed oil in rats. III. Studies in germ-free rats

The morphological effects on the myocardium of feeding rapeseed oil were compared in conventional and germ-free rats in short-term experiments (10 days). It was concluded that the fatty accumulation in the heart muscle cells occurring in rats fed rapeseed oil was not influenced by the presence or absence of a normal intestinal flora. In long-term experiments (80 days) under similar conditions, the myocardial effects of feeding germ-free rats with conventional rapeseed oil, rapeseed oil from the Canadian cultivar Oro very low in erucic acid, or arachis oil were studied in serial sections. Severe myocardial lesions developed in the group of rats fed conventional rapeseed oil, while in the other two groups the myocardium was completely normal. These results give no support to the theory that other factors than C22:1 acids in rapeseed oil are responsible for the myocardial lesions.