Abstract
Department of Animal Science, Faculty of Agriculture, Tohoku University, Sendai Effect of goitrin (goitrogen in rapeseed) upon nitrogen balance was investigated in mature male rats weighing about 360g fed either normal protein diet (CP 16.5%) or low-protein diet (CP 5%) . Crystalline goitrin prepared from rapeseed (Brassica napus) was mixed into the diets at level of 0.05% and fed to rats for 14 days. Digestibility of dry matter, gross energy and crude protein were not affected by administration of goitrin in the both diets. Administration of goitrin increased retention of nitrogen in rats fed the normal protein diet. On the other hand, administration of goitrin caused decrease of feed consumption and of nitrogen retention in rats fed the low-protein diet. Endogenous urinary nitrogen per head and metabolic fecal nitrogen per g of feed intake were not affected by administration of goitrin when nitrogen-free diet was fed.
