Location: Natural Resource Management ResearchTitle: Treatment of flaxseed to reduce biohydrogenation of a-linolenic acid by ruminal microbes in sheep and cattle and increase n-3 fatty acid concentrations in red meat Author
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/23/2012
Publication Date: 12/19/2012
Citation: Kronberg, S.L., Scholljegerdes, E.J., Murphy, E.J., Ward, R.E., Maddock, T.D., Schauer, C.S. 2012. Treatment of flaxseed to reduce biohydrogenation of a-linolenic acid by ruminal microbes in sheep and cattle and increase n-3 fatty acid concentrations in red meat. Journal of Animal Science. 90:4618-4624. DOI: 10.2527/jas.2011-4774. Interpretive Summary: There is considerable evidence that the health of many people could be improved by greater intake of omega-3 fatty acids. Red meat can be a source of omega-3 fatty acids. We conducted a study to determine if omega-3 fatty acid concentrations could be increased in the muscle of sheep and cattle by feeding them flaxseed that was treated to protect the common plant omega-3 fatty acid from being converted to more saturated fatty acids by microbes in the rumen of sheep and cattle. We found that consumption of treated flaxseed raised omega-3 fatty acid concentrations in the blood and muscle of lambs and in the blood of steers but did not raise omega-3 fatty acid concentrations in the muscle of the steers. Supplementing the diets of forage-fed lambs with flaxseed that is treated to reduce conversion of ALA by ruminal microbes can increase concentrations of omega-3 FA in the muscle of lambs; however, alternatives are needed to protect the omega-3 fatty acid in flaxseed from microbial conversion in the rumen of cattle on grain-based diets.
Technical Abstract: Our study determined if flaxseed treated with a formaldehyde-free process increased n-3 fatty acid (FA) levels in ruminant muscle. Twenty-four lambs (initial BW 43.8 ± 4.4 kg) were randomly divided into 4 groups for a 90-d trial. One treatment group (FLX) was fed 136 g/d of non-treated ground flaxseed, another treatment group (FLXT1) was fed 136 g/d of flaxseed treated to protect a-linolenic acid (ALA) from microbial hydrogenation, a third treatment group (FLXT2) was fed 136 g/d of a second treated flaxseed, and a fourth treatment group (CNTL) was fed corn and soybean meal with similar CP and DE levels as the other treatments. Intake of treated flaxseed raised plasma triacylglycerol concentrations of ALA more (P < 0.01) than intake of non-treated flaxseed did, but there was no difference (P = 0.65) in ALA increase between FLXT1 and FLXT2. Intake of treated flaxseed increased (P = 0.05) muscle phospholipid ALA and eicosapentaenoic acid (EPA) concentrations more than non-treated flaxseed did. There were no differences in muscle phospholipid n-3 concentrations between FLXT1 and FLXT2. Ten yearling steers (initial BW 437 ± 18 kg) were randomly divided into two groups. One group was fed ground flaxseed (0.05% BW/steer/d; FLX; n = 5), and a second group was fed treated flaxseed at the same rate (FLXT; n = 5). The 175-d trial was divided into 2 periods –a high roughage, low concentrate period then a high concentrate, low roughage period. Steers were fed rations that were formulated to be isonitrogenous, isocaloric, and isolipidic. There was no difference (P = 0.37) in elevation of ALA in blood plasma of FLX and FLXT groups at end of first period. However, FLXT had 16% higher (P = 0.003) concentration of ALA in their plasma during the second period. Muscle phospholipid n-3 FA were not greater (P = 0.55) for steers in the FLXT group. Intake of treated flaxseed raised n-3 concentrations in blood and muscle of lambs and in blood of steers but did not raise n-3 FA concentrations in muscle of steers. Supplementing the diets of forage-fed lambs with flaxseed treated to reduce hydrogenation of ALA by ruminal microbes can increase concentrations of n-3 FA in the muscle of the lambs.