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

Abstract

The chemical composition and nutritional value of seeds, press-cakes and solvent meals produced under the same processing conditions from yellow-seeded spring Brassica rapa (YSR), and dark-seeded winter Brassica napus (DSR) rape were determined. Both varieties were of double low type. YSR products contained 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 two 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 respective 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 evaluated products and better on YSR than DSR cake and meal.