Effect of flame roasting on the nutritional quality of common cereal grains for non-ruminants and ruminants

The effect on nutritional quality of barley, maize, oats and wheat after flame roasting at 3 temperatures for each cereal (between 74 and 193 degrees C) in a commercial propane heated roaster at 67, 100 and 133% of the manufacturer's suggested temperatures was studied. A sample of unroasted material was included for each grain. Evaluation as non-ruminant feeds was done using a rooster bioassay. For ruminants, DM and crude protein degradation in the rumen and intestinal digestibility were estimated. Roasting had little effect on any non-ruminant estimate of utilization but it decreased (P<0.05) effective rumen degradation and rumen degradation rates of DM and crude protein for all grains, although the effect was least for maize. Total tract digestibility in ruminants was not affected by roasting, except for oats and wheat, which was reduced at the highest level of roasting. For ruminant diets, heat treatment by roasting of wheat and barley may be beneficial, resulting in a slower release of nutrients in the rumen and allowing more DM and crude protein to escape degradation in the rumen and be digested in the small intestine..