Submitted to: Lipids Journal
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/15/2006
Publication Date: 11/30/2006
Citation: Kronberg, S.L., Barcelo-Coblijn, G., Murphy, E.J. 2006. Bovine muscle n-3 fatty acid content is increased with flaxseed feeding. Lipids J. 41:1059-1068. Interpretive Summary: Americans may be healthier if they would increase their intake of omega-3 fatty acids. These fatty acids are abundant in fish such as salmon and tuna, but many Americans do not eat these fish or do not eat them frequently enough. Consequently, omega-3 enriched sources of the foods that they eat regularly are needed. We conducted a study to determine if higher levels of omega-3 fatty acids could be achieved faster in beef by feeding flaxseed treated with the lignosulfonate process to reduce bio-hydrogenation (destruction) of omega-3 fatty acids in the rumen by rumen microbes and thereby increase omega-3 fatty acids available to and incorporated into bovine muscle cells, and secondly to determine if grilling ribeye steaks would change their fatty acid composition. In summary, omega-3 levels in Hereford beef were clearly enhanced by feeding lignosulfonate-treated flaxseed for 71 days, but not to the extent desired. An improved method for protecting the omega-3 fatty acid in flaxseed (alpha-linolenic acid) from bio-hydrogenation in the bovine rumen and (or) more days of feeding lignosulfonate-treated flaxseed are needed to obtain higher levels of omega-3 fatty acids in beef. If steaks are grilled to an internal temperature of 64 degrees C or less, little or no loss of omega-3 fatty acid will occur in the meat.
Technical Abstract: The objectives of this study were to determine if higher levels of n-3 fatty acids (FA) could be achieved faster in beef by feeding flaxseed treated with the lignosulfonate process to reduce bio-hydrogenation of n-3 FA in the rumen and thereby increase n-3 FA available to and incorporated into bovine muscle cells, and secondly to determine if grilling ribeye steaks would change their FA composition. Diets of Hereford steers were supplemented with or without flaxseed (907 g/steer/d) for 71 d that was treated with the lignosulfonate process. Biopsies were taken from longissimus dorsi muscles of these steers at the end of the supplementation period and FA mass, composition and associated parameters were determined for these samples. Angus steers were fed a diet that included untreated ground flaxseed (454 g/steer for 22 d followed by 907 g/steer for 110 d) then were slaughtered, and one ribeye steak from each steer was sampled before and after grilling to an internal temperature of 64 degrees C on a barbeque grill. These samples were analyzed as described above. Feeding lignosulfonate-treated flaxseed for 71 d increased n-3 FA mass in beef considerably (300, 43, and 33% for ALA, EPA, and DPA, respectively), but not to the extent desired (only 12, 10, 30, and 3 mg/100g for ALA, EPA, DPA and DHA, respectively). Improved methods for protecting n-3 FA from bio-hydrogenation by rumen microbes may allow for greater enrichment of n-3 FA in beef. Grilling ribeye steaks to an internal temperature of 64 degrees C induced little change in their FA composition.