The effects of high and low erucic acid rapeseed oils in diets for rats

Fully refined rapessed oils of high (regular rapeseed oil, B. campestris) and low erucic acid content (Span oil, B. campestris; commercially hydrogenated Span oil and Zephyr oil, B. napus) and soybean oil were fed to male and female Sprague-Dawley rats at a level of 15% by weight in the diet. In the first experiment, 5 male and 5 female rats per treatment were housed individually, whereas in the second experiment 5 male or 5 female rats per treatment were housed in groups of five. Body weight gain was not influenced by the dietary treatments in experiment 1. However, in experiment 2 the groups fed the diets containing regular rapeseed oil or Span oil showed significantly (P less than 0.05) lower body weight gains when compared to soybean oil fed groups but not when compared to the hydrogenated Span or Zephyr oil fed groups. Focal lesions were found in cardiac tissue of the rats, but not in liver and spleen tissue. The incidence of lesions was similar on all ration treatments. A significantly (P LESS THAN 0.01) higher incidence of cardiac lesions was found in male rats than in female rats.