Distiller’s Dried Grains with Solubles Affects Fatty Acid Composition of Beef

Sixteen steers (BW = 394.7 - 20.7 kg) were allotted by weight to 1 of 2 treatments to test the effects of distiller’s dried grains with solubles (DDGS) on the fatty acid profile of muscle tissue. Treatments consisted of a whole shelled corn, soybean hulls, and alfalfa hay based finishing diet with DDGS included at 16% of DM or soybean meal and cracked corn (control), which were fed for approximately 77 d. Diets were formulated to be isocaloric at 1.44 and 1.45 Mcal of NEg/kg of DM for DDGS and control treatments, respectively. At slaughter, a 2.5 cm thick cross section of the LM was taken between the 11th and 12th rib; all external fat around the cut was removed, and the cut was stored at -80°C for later analysis. The chemical composition of LM (i.e., moisture, crude fat, CP, and ash) did not differ (P > 0.10) between treatments. Fat tissue extracted from LM samples was separated into triacylglycerol and phospholipid fractions and analyzed for fatty acid composition. There was no effect of treatment on the fatty acid composition of the triacylglycerol fraction. However, in the phospholipid fraction, DDGS increased (P < 0.05) linoleate (18:2n6 cis; 29.3 vs. 20.7%, respectively) and PUFA (43.7 vs. 32.5%, respectively) in LM samples compared with control. In conclusion, DDGS increased the amount of unsaturated fatty acids in the phospholipid but not the triacylglycerol fraction of LM.