Valorization of rapeseed meal. 3. Effects of glucosinolate content on food intake, weight gain, liver weight and plasma thyroid hormone levels in growing rats.

Seven groups of 10 growing rats each were fed a control diet or rapeseed diets with glucosinolate contents ranging from 4.4 to 36.6 mM/kg DM. After a 5-day adaptation period, the rats were fed ad libitum for 17 days. The food intake of the experimental groups was maximal after 11 days and was, on an average, 4 to 45% lower than that of the control group. The differences were still greater during the last 7 days. Daily weight gain was also maximal after 8 days and began to decrease, dropping to 1 g during the last days. There were negative curvilinear relationships between food intake or weight gain and diet glucosinolate content. Liver weight (g/100 g of body weight) was not significantly altered by glucosinolate intakes between 0.08 and 0.39 mM/day. However, in the groups fed the diets with the lowest glucosinolate contents, plasma triiodothyronine (T3) and thyroxine (T4) levels were 50% lower than in the control group and 70 or 80% lower, respectively, with the diets having the highest glucosinolate contents.