Comparison of fatty acids in beef tissues from conventional, organic and natural feeding systems in western Canada

Turner, T. D., Jensen, J., Pilfold, J. L., Prema, D., Donkor, K. K., Cinel, B., Thompson, D. J., Dugan, M. E. R. and Church, J. S. 2015. Comparison of fatty acids in beef tissues from conventional, organic and natural feeding systems in western Canada. Can. J. Anim. Sci. 95: 49–58. The effect of production system on intramuscular and associated trim fatty acid (FA) profiles of retail ribeye steaks from conventional and niche market organic and natural (grain- or grass-fed) beef were compared. Meat from organic grain- and grass-fed systems was leaner, containing greater proportions of polyunsaturated FA, i.e., 18:3n-3, 20:5n-3, 22:5n-3, 22:6n-3. Correspondingly, the n-6/n-3 ratios of organic grain- and grass-fed systems were 3:1, while conventional and natural grain systems had ratios of 8:1. High forage-to-grain ratio production systems increased proportions of desirable biohydrogenation intermediates (BI), including t11-18:1 and c9,t11-18:2, whereas conventional and natural grain systems elevated t10-18:1. Trim fat was similarly affected by production system, and was a relatively richer source of BI. Overall, proportions of desirable FAs, including n-3 and BI, were greater for organic grain- and grass-fed systems, emphasizing the importance of a high forage-to-grain ratio to enhance the healthfulness of beef, whereas conventional and natural grain-fed systems were largely equivalent.