Maize dried distillers grains with solubles (DDGS) is a widely used alternative feed ingredient in swine diets, with an metabolizable energy (ME) content comparable to maize (Stein and Shurson, 2009). However in recent years, most ethanol plants have been extracting maize oil, thereby producing reduced-oil DDGS. Oil extraction has resulted in large variability in ether extract (EE; 50–120 g/kg) and ME content among DDGS sources (Kerr et al., 2013), which may increase the risk of inaccurate diet formulations. Although the reduction in oil content was expected to reduce ME content of DDGS, Kerr et al. (2013) showed that EE content was a poor predictor of ME content.
Prediction equations (Pedersen et al., 2007; Anderson et al., 2012; Kerr et al., 2013) and a commercial service (ILLUMINATE; Nutriquest, Mason City, IA) have been developed to predict ME content of DDGS sources based on chemical composition. Cross-validation of published equations by Urriola et al. (2014) indicated that using the combination of equations from Anderson et al. (2012): Digestible energy (DE) = −2,161 + (1.39 × gross energy; GE) − (20.7 × neutral detergent fiber; NDF) − (49.3 × EE) and ME = −261 + (1.05 × DE) − (7.89 × crude protein; CP) + (2.47 × NDF) − (4.99 × EE), generated the most accurate and precise ME estimates for DDGS. However, these estimates require validation using growth performance data.
Feeding diets containing a traditional high-oil (>100 g/kg EE) DDGS source reduced belly and pork fat firmness because maize oil contains a high concentration of polyunsaturated fatty acids (PUFA; Stein and Shurson, 2009; Xu et al., 2010a; Davis et al., 2015). Pork fat quality may be improved by feeding DDGS sources with less oil content, but limited data are available to show the magnitude of this improvement. The objectives of this study were to determine the effects of feeding diets containing 40% DDGS with variable oil content on growth performance, carcass traits, and pork fat quality of growing-finishing pigs, and to evaluate the ME predictions for DDGS using the Anderson et al. (2012) equations and ILLUMINATE® estimates.