Compositional effects of corn distillers dried grains with solubles with variable oil content on digestible, metabolizable, and net energy values in growing pigs

Two experiments were conducted in growing-finishing pigs to determine the DE and ME (Exp. 1, 96.3 kg of BW) and NE (Exp. 2, 45.4 kg of BW) content of corn distillers dried grains with solubles (C-DDGS), and to refine or develop DE, ME, and NE prediction equations based on chemical composition of C-DDGS. Composition of the 6 C-DDGS sources varied (ash, 4.71 to 5.63%; CP, 29.65 to 32.21%; ether extract, 6.99 to 13.34%; NDF, 38.27 to 39.58%; total dietary fiber, 31.12 to 32.81%; DM basis), with the determined DE ranging from 3,836 to 4,038 kcal/kg of DM, ME from 3,716 to 3,893 kcal/kg of DM, and NE from 2,107 to 2,310 kcal/kg of DM. Regardless of the range in C-DDGS composition and the resulting DE, ME, or NE value, no chemical parameter measured (GE, CP, starch, total dietary fiber, NDF, ADF, hemicellulose, ether extract, or ash) was significant at P ≤ 0.15 to be retained in the regression model to predict DE, ME, or NE content in the C-DDGS sources evaluated. Apparent total-tract digestibilities of several nutritional components were also measured for comparative purposes but were not included in the prediction model. On average, the C-DDGS used in these studies contained 3,931, 3,793, and 2,207 kcal of DE, ME, and NE per kilogram of DM, respectively. These results suggest that C-DDGS composition and subsequent DE, ME, and NE can be highly variable and that a wider range in ingredient chemical composition and DE, ME, and NE values, as well as more C-DDGS sources, appear to be necessary to generate energy-prediction equations than used in the current experiments.