Composition and nutritional value for chickens and rats of seeds, cake andsolvent meal from low-glucosinolate yellow-seeded spring rape and dark-seeded winter rape

The chemical composition and nutritional value of seeds, press-cakes and so lvent meals produced under the same processing conditions from yellow-seede d spring Brassica rapa (YSR), and dark-seeded winter Brassica napus (DSR) r ape were determined. Both varieties were of double low type. YSR products c ontained more protein and less fibre than DSR products, YSR meal contained less glucosinolates and had a similar concentration of amino acids (g/16 gN ) as DSR meal. The nutritional value of DSR and YSR seeds and products was evaluated in tw o experiments on 261 broiler cockerels; press-cakes and solvent meals also in 4 experiments on 212 male rats. In chickens, the energy value of all YSR products was considerably higher than DSR due to greater fat digestibility . In rats, the nutritional value of protein (TD, BV, NPU) and energy value of YSR cake and meal were similar or marginally greater than of the respect ive DSR products. Growth performance of chickens fed isoenergetic diets containing 20% of YSR and DSR meal did not differ from controls. In rats, feed intake and growth rate were negatively correlated with the glucosinolate level in the evalua ted products and better on YSR than DSR cake and meal.