April 22/Life Science Weekly -- According to a U.S. study, "Milk with an increased content of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and conjugated linoleic acid (CLA) was obtained by incorporating fish oil into the feed of cows. The four feed treatments used were a control diet of 57% forage and 43% concentrate mix with EnerGII fat supplement at 1.65% of dietary DM, or EnerGII in the basal diet was partially replaced with 1) 0.21% partially ruminally inert calcium salts of 71% fish oil given at 0.41% of DM; 2) 0.41% inert calcium salts of 71% fish oil given at 0.83% of DM; or 3) 0.83% inert calcium salts of 43% fish oil given at 0.83% of DM."
"The cows were milked after 5- and 8-week, and the EPA, DHA, and CLA contents in the pasteurized whole milk were determined. The presence of off-flavors in the milk was investigated after three and 10 days of storage. Twelve judges were trained to evaluate the presence of grassy, fishy, oily, oxidized and rancid off-flavors. Although levels of EPA, DHA, vaccenic acid and CLA increased for all four treatments, a trained sensory panel detected no difference in milk flavor between treatments and the control, with little or no intensity of off-flavors. Results suggest that feeding fish oil and EnerGII at varying levels enhanced CLA, EPA, DHA, and total n-3 fatty acids in milk over the length of the experiment without negatively affecting milk flavor," wrote K.A.S. Nelson and colleagues, Utah State University.
The researchers concluded, "This creates the potential for a more marketable and healthful product."
Nelson and colleagues published their study in the Journal of Dairy Science ("Increasing omega fatty acid content in cow's milk through diet manipulation: Effect on milk flavor." Journal of Dairy Science, 2009;92(4):1378-1386).
For more information, contact S. Martini, Utah State University, Dept. of Nutrition & Food Science, Logan, UT 84322.
From the April 27, 2009, Prepared Foods E-dition