Impact of finishing diets with de-oiled distillers grains or antioxidant containing supplement on beef shelf life

In its entirety this dissertation intended to address the impact of feeding several forms of de-oiled corn distillers grains plus solubles and the effect of supplementing OmniGen-AF as a potential antioxidant source for extending beef shelf life. In study one we learned that despite the de-oiling process, greater inclusion levels (65%, DM basis) of de-oiled wet distillers grains plus solubles (WDGS) causes an increase in polyunsaturated fatty acids (PUFA) similar to the levels obtained with full-fat WDGS. Lower inclusion levels (35 and 50%, DM basis) of de-oiled WDGS have intermediate PUFA content in comparison to 65% de-oiled WDGS, full-fat WDGS and a corn control diet (P \u3c 0.01). In study two cattle finished with 50% de-oiled dry distillers grain plus solubles (DDGS) also resulted in an increased PUFA content in muscle in relation to a corn control group (P \u3c 0.0001). In this instance treatment by retail display interactions indicated that steaks from cattle on the 50% de-oiled DDGS diet had lower color and lipid stability at prolonged retail display times than did the steaks from cattle on the corn control diet (P \u3c 0.0001). In general, the first two studies indicate that even after the de-oiling process and regardless of the moisture content of the distillers grains, feeding corn distillers grains plus solubles increases PUFA content, which in turn negatively impacts beef shelf life. Therefore, it is important to consider this when utilizing these by-products for finishing rations, the addition of antioxidants may be beneficial to off-set any potential detrimental effects of distillesrs grain on beef shelf life. In study three, OmniGen-AF, a potential antioxidant supplement was evaluated. OmniGen-AF supplementation all through the finishing period caused an increase in PUFA content relative to cattle supplemented only through the receiving phase (P = 0.01). Feeding OmniGen-AF all through the finishing phase however did not alter color, lipid stability, or superoxide dismutase activity (P \u3e 0.05). Therefore, in order to consider OmniGen-AF as an effective antioxidant source it may need to be fed at a greater concentration (greater than 4g/45.36kg BW/hd/d) or perhaps more potent antioxidants merit evaluation, particularly in feedlot rations utilizing corn distiller by-products