ARS | Publication request: 35% corn wet distiller's grains plus solubles in steam-flaked and dry-rolled corn based diets: Effects on fatty acids, sensory attributes, and shelf-life of loins

Submitted to: Experiment Station Bulletins
Publication Type: Experiment Station
Publication Acceptance Date: September 1, 2008
Publication Date: N/A

Interpretive Summary: The availability and concurrent use of wet distiller's grains plus solubles (WDGS) in finishing diets for beef cattle continues to increase as the ethanol industry expands. While much of the research focus has been on the energy value of WDGS relative to the corn it replaces, recent questions have been posed related to the effects of feeding WDGS on beef quality. These concerns are based primarily on the premise that replacing corn, which is primarily starch, with WDGS, which has essentially no starch, will reduce blood glucose and negatively impact the deposition of intramuscular fat (marbling). Furthermore, incorporation of WDGS into steam-flaked corn (SFC) based finishing diets may be especially detrimental to marbling because steam-flaking increases ruminal starch digestion, thereby reducing glucose absorption in the small intest6ine relative to dry-rolled corn (DRC) based diets. Additionally, there are limited data available on the impacts of feeding WDGS on consumer sensory attributes and shelf-life. Therefore, the objective of this research was to determine the impacts of feeding 35% WDGS in SFC- and DRC-based finishing diets on marbling, sensory attributes, and shelf-life of beef loins. In the study, 54 crossbred steers were fed DRC- or SFC-based finishing diets that contained 0% or 35% WDGS (dry matter basis). The monounsaturated: saturated fatty acid ratio of lipids within the longissimus muscle (i.e. ribeye) was strongly decreased by WDGS (P < 0.01), indicating a decrease in intramuscular fat cell differentiation. Although the differences in sensory attributes caused by dietary treatments were statistically significant, they were small in actual magnitude and probably of no practical significance. Inclusion of WDGS into finishing diets increased lipid oxidation after five days of storage (P = 0.01). These data indicate that feeding 35% WDGS in DRC- and SFC-based finishing diets may negatively impact intramuscular adipocyte differentiation and decrease shelf-life, but likely have little impact on beef taste and quality.

Technical Abstract: Fifty-four crossbred steers were fed dry-rolled corn (DRC) or steam-flaked corn (SFC) based finishing rations with or without 35% wet distiller's grain plus solubles (WDGS) to determine effects of corn processing method and WDGS inclusion on marbling attributes, sensory attributes, and shelf-life of beef loins. The monounsaturated: saturated ratio of fatty acids from longissimus muscle was strongly decreased by WDGS (P < 0.01), indicating a depression of intramuscular adipocyte differentiation. Differences in sensory attributes due to dietary treatment were statistically significant, but minimal in magnitude. Inclusion of WDGS into finishing diets increased lipid oxidation after five days of storage (P = 0.01) as measured by thiobarbituric acid reactive substances. These data indicate that feeding 35% WDGS in DRC- and SFC-based finishing diets may negatively impact intramuscular adipocyte differentiation and decrease shelf-life, but likely have little impact on beef taste and quality.