Effects of Chemical Treatment of Whole Canola Seed on Digestion of Long-Chain Fatty Acids by Steers Fed High or Low Forage Diets

¹ Department of Animal Sciences, University of Illinois, Urbana 61801
² Department of Animal Sciences, University of Illinois, Urbana 61801

The objective was to evaluate the effectiveness of alkaline H₂O₂ treatment of whole canola seed as a means of weakening the seed coat while simultaneously protecting long-chain unsaturated fatty acids from ruminal biohydrogenation without hindering their digestion in the lower gut. Six ruminally and duodenally cannulated beef steers were offered six isonitrogenous diets for ad libitum intake twice daily in a 6 x 6 Latin square design. Treatments were arranged as a 2 x 3 factorial with two forage percentages (70 vs. 30% of dietary DM as a corn silage) and three forms of canola seed supplementation, including no canola seed or canola seed added at 10% of dietary DM as treated whole seed or as crushed seed. Canola seed contributed 5% added fat to the total diet. Treated 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, digestibilities of these long-chain fatty acids (as percentages of the amounts entering the small intestine) did not differ between diets containing canola seed as treated whole seed or crushed seed. Results suggest that chemically treated whole canola seed can be used as a means of postruminal delivery of digestible long-chain unsaturated fatty acids, especially C_18:1, which contributes 62% of the total fatty acids in canola seed. Results also suggest that treated whole canola seed may be more beneficial when fed with low than with high forage diets.

Key Words: canola seed • forage percentage • fatty acids • steers

Submitted on October 11, 1994
Accepted on October 6, 1995