INFLUENCE OF PHYSICAL TREATMENT OF RAPE E XPELLER, WHEAT, MAIZE AND MAIZE GLUTEN FEED ON DEGRADABILITY IN THE RUMEN AND ON THE ENZYMATIC IN-VITRO DIGESTIBILITY OF NONDEGRADED CRUDE PROTEIN

The influence of physical treatment-expansion and flaking-on crude pro teins degradability in the rumen was studied in maize, maize-gluten fe ed, rape extracted meal and in the expanded one at 120 degrees C and 1 50 degrees C, rape cake, wheat and flaked wheat by in sacco method. Th e enzymatic digestibility of crude protein in the rumen undegraded res idues of the above mentioned feeds was determined by an enzymatically in vitro method. The treatment of feed decreased significantly the ori ginal solubility and theoretical degradability of crude proteins, and the amount of undegraded crude proteins was increased. Positive influe nce on the amount of enzymatically digested crude protein was determin ed in rape expanded at 120 degrees C and 150 degrees C (60, 61 and/or 68%). Flaking of wheat had a similar effect. Enzymatic digestibility a t undegraded rests where increased by 8-10% after the heat treatment a nd it remained almost unchanged in expanded maize-gluten feed.