CHEMICAL CHARACTERIZATION AND NUTRIENT AVAILABILITY OF HIGH AND LOW-FIBER CANOLA-MEAL

Tail-end dehulling separates regular canola meal (CM) into low (LFCM) and high (HFCM) fiber fractions. The study was designed to study the e ffects of tail-end dehulling of CM on the chemical composition, rumina l nutrient degradability, and intestinal protein availability of the r esulting HFCM and LFCM fractions. Relative to LFCM and CM, HFCM had hi gher (P < 0.05) neutral (NDF) and acid (ADF) detergent fiber and acid detergent lignin (ADL) levels. Canola meal had higher (P < 0.05) ADF a nd ADL but not NDF relative to LFCM. Crude protein (CP) was lower (P < 0.05) in HFCM than in CM and was lower (P < 0.05) in CM than in LFCM. Neutral and acid detergent insoluble CP followed the pattern of NDF a nd ADF, respectively. Protein fractionation showed no difference in no n-protein nitrogen between the three meals. True protein was lower (P < 0.05) in HFCM than CM and LFCM. Sub-fractionation of true protein re sulted in a B-1 fraction of 148, 145, and 129 g kg(-1) for CM, LFCM an d HFCM, respectively. Respective values for B-2 and B-3 fractions were 768, 769, and 751 g kg(-1) and 84, 86, and 120 g kg(-1). Results indi cated that ruminal effective degradability of dry matter and ADF was l ower (P < 0.05) in HFCM relative to CM and was lower in CP relative to LFCM. Ruminal effective degradability of CP and NDF was lower in HFCM than in CM and LFCM. No differences were observed between CM and LFCM . Intestinal digestibility of rumen undegraded protein was higher (P < 0.05) in LFCM than in CM and was higher (P < 0.05) in CM than in LFCM . It was concluded that tail-end dehulling of canola meal resulted in a LFCM with higher protein and lower NDF and ADF content and improved nutrient availability and a HFCM with a lower protein and a higher fib er (particularly ADF) content and reduced nutrient availability. Furth er studies are required to determine the effect of feeding HFCM on rum inant performance.