EFFECT OF FLAME ROASTING ON THE NUTRITIONAL QUALITY OF COMMON CEREAL-GRAINS FOR NONRUMINANTS AND RUMINANTS

The effect on nutritional quality of barley, corn, oats and wheat afte r flame roasting at three temperatures was evaluated. Batches of barle y, corn, oats or wheat were flame roasted in a commercial propane heat ed roaster at 67, 100 and 133% of the manufacturer's suggested tempera tures. A sample of non-roasted material was also included for each gra in. Evaluation as non-ruminant feeds was done using a rooster bioassay . For ruminants, the dry matter and crude protein degradation in the r umen and intestinal digestibility were determined. Roasting had little effect on any non-ruminant estimate of utilization but it significant ly (P<0.05) decreased effective ruminal degradation and ruminal degrad ation rates of dry matter and crude protein for all grains, although t he effect was least for corn. Total tract digestibility in ruminants w as not affected by roasting, except for oats and wheat which was reduc ed at the highest level of roasting. For ruminant diets, heat treatmen t by roasting of wheat and barley may be beneficial, resulting in a sl ower release of nutrients in the rumen and allowing more dry matter an d crude protein to escape degradation in the rumen and be digested in the small intestine.