Increasing omega fatty acid in cow's milk through diet manipulation: Effect on milk flavor.

This topic was addressed by K.A.S. Nelson and S. Martini in a paper called: Increasing omega fatty acid in cow's milk through diet manipulation: Effect on milk flavor. The paper was published in the Journal of Dairy Science, Volume 92, pages 1378-1386.

It is well-recognized that the n-3 fatty acids, specifically EPA and DHA, also known as the omega fatty acids, play a significant role in reducing the risk of cardiovascular disease, hypertension and certain autoimmune and inflammatory diseases. The possible health benefits of the associated conjugated linoleic acid (CLA) are anticarcinogenic, antiobesity, growth promotion and immunomodulation. Fish oil is the richest source of EPA and DHA, whereas dairy products and ruminant meat normally supply the greatest concentrations of CLA in the human diet. However, the dietary supply remains marginal which emphasizes the need to increase concentrations. Here is where the problem lies: adding fish oil to dairy products during manufacturing often result in suboptimal texture and off or fishy flavors. A more acceptable way is to try and increase these acids in the milk of cows by dietary manipulation. This is the approach adopted by the authors in this investigation.

In their trial one group of cows were fed a Control diet with a standard fat supplement containing no fish oil, and fed at 1.65% of feed dry matter (DM); in a second group 0.41% of the 1.65% standard fat supplement was replaced by 0.21% partially rumen-inert calcium salts containing 71% fish oil; in a third group 0.41% rumen-inert calcium salts containing 71% fish oil replaced the standard fat supplement to the extent of 0.83% of feed DM, whereas in the fourth group 0.83% rumen-inert calcium salts containing 43% fish oil were fed at a level of 0.83% of feed DM. Thus, in the four treatments progressively more EPA, DHA and CLA should have been protected from rumen fermentation and reached the small intestine to be absorbed intact. The results show that this in fact was successful as increases in the n-3 fatty acids were recorded to the extent of 100-200%. Another positive was that despite the substantial increase in these acids as a result of the increasing concentration of fish oil fed, a trained sensory panel could not detect any difference in milk flavor between the Control and the fish oil containing treatments, neither could they detect significant evidence of off flavors. This is promising for milk and the quest to create even more healthy and marketable products, but it should be realized that flavor is but one of the characteristics that define high quality dairy products.