In Exp. 1, five samples of DDGS-ethanol were sourced from Minnesota (MN1, MN2), Illinois (IL1, IL2), and from Kentucky (KY). In Exp. 2, six samples of DDGS-ethanol, 1 sample of DDG, and 1 sample of DDGS-beverage were used to compare values for apparent ileal digestibility and standardized ileal digestibility (SID) of AA between DDGS-ethanol and DDGS-beverage and between DDG and DDGS-ethanol.
Results of Exp. 1 showed that the SID of Lys in DDGS from MN2 (72.8%) was greater (P < 0.01) than in DDGS from MN1 (66.8%), IL1 (66.8%), and KY (65.8%) but not different from IL2 (70.1%). Except for Leu and Glu, no differences in SID for any of the other AA were observed among the 5 sources of DDGS. In Exp. 2, the SID for Lys in DDGS-beverage was greater (P < 0.01) than in DDGS-ethanol (69.3 vs. 64.8%), but for CP and all other AA except His, no differences between the 2 types of DDGS were observed. The SID for most AA in DDG was greater (P < 0.05) than in DDGS-ethanol, which suggests that the AA in the solubles that are added to DDGS may be less digestible than the AA in DDG.
In conclusion, results of these experiments confirm that the digestibility of Lys is more variable among sources of DDGS than the digestibility of other AA. However, the SID of AA among DDGS sources within a region can vary as much as among DDGS sources from different regions, and AA in DDGS-beverage may be as digestible as AA in DDGS-ethanol. The digestibility of AA in DDG is greater than in DDGS, which indicates that AA in the solubles has a lower digestibility than AA in DDG.
AA Pahm, C Pedersen, D Hoehler and HH Stein 2008. Journal of Animal Science, 86:2180-2189.