EFFECTS OF CHEMICAL TREATMENT OF WHOLE CANOLA SEED ON DIGESTION OF LONG-CHAIN FATTY-ACIDS BY STEERS FED HIGH OR LOW FORAGE DIETS

The objective was to evaluate the effectiveness of alkaline H2O2 treat ment of whole canola seed as a means of weakening the seed coat while simultaneously protecting long-chain unsaturated fatty acids from rumi nal biohydrogenation without hindering their digestion in the lower gu t. Six ruminally and duodenally cannulated beef steers were offered si x isonitrogenous diets for ad libitum intake twice daily in a 6 x 6 La tin square design. Treatments were arranged as a 2 x 3 factorial with two forage percentages (70 vs. 30% of dietary DM as corn silage) and t hree forms of canola seed supplementation, including no canola seed or canola seed added at 10% of dietary DM as treated whole seed or as cr ushed seed. Canola seed contributed 5% added fat to the total diet. Tr eated whole canola seed was superior to crushed seed in increasing the amounts of C-18:1, C-18:2, and C-18:3 flowing to the duodenum and the amounts digested postruminally. However, digestibilites of these long -chain fatty acids (as percentages of the amounts entering the small i ntestine) did not differ between diets containing canola seed as treat ed whole seed or crushed seed. Results suggest that chemically treated whole canola seed can be used as a means of postruminal delivery of d igestible long- chain unsaturated fatty acids, especially C-18:1, whic h contributes 62% of the total fatty acids in canola seed. Results als o suggest that treated whole canola seed may be more beneficial when f ed with low than with high forage diets.