Evaluation of dietary rapeseed protein concentrate flours in rats and dogs

Abstract

Two high-protein concentrate flours made from rapeseed ( Brassica spp.) were fed to growing dogs and rats for 90 days in semisynthetic diets. The oxazolidinethione concentrations of the two types of flour were of the order of 0.287 and 0.02 mg/g. In each experiment, 20 and 40% of the total dietary protein was supplied by the rapeseed flour (RSF); the balance was supplied as casein. Control groups received only casein. Only a low order of antithyroid activity was detected in the flours used. Measures of thyroid 131I uptake, serum thyroxine concentration, thyroid weight, and histology remained essentially normal. Serum glutamic-pyruvic transaminase activity was decreased by RSF, while packed cell volume and erythrocyte counts increased in the rats. No treatment-associated abnormalities were noted in the dogs. It was concluded that the antithyroid effects of the RSF used in this study were substantially reduced compared to the RSF used in other studies.