Factors affecting the variability in ileal amino acid digestibility in corn distillers dried grains with solubles fed to growing pigs

A. A. Pahm,* C. Pedersen,† D. Hoehler,‡ and H. H. Stein*

*Department of Animal Sciences, University of Illinois, Urbana 61801; †Danisco Animal Nutrition, SN8 1AA Marlborough, Wiltshire, UK; and ‡Evonik Degussa Corp., Kennesaw, GA 30144

Two experiments were conducted to compare the ileal digestibility of AA in distillers dried grains with solubles (DDGS) sourced from different regions (IL, MN, KY), to compare AA digestibility in DDGS and in distillers dried grains (DDG) and to compare AA digestibility in DDGS from ethanol production (DDGSethanol) and DDGS from beverage production (DDGSbeverage). In Exp. 1, five samples of DDGSethanol were sourced from Minnesota (MN1, MN2), Illinois (IL1, IL2), and from Kentucky (KY). In Exp. 2, six samples of DDGSethanol, 1 sample of DDG, and 1 sample of DDGSbeverage were used to compare values for apparent ileal digestibility and standardized ileal digestibility (SID) of AA between DDGSethanol and DDGSbeverage and between DDG and DDGSethanol. 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 DDGSbeverage was greater (P < 0.01) than in DDGSethanol (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 were greater (P < 0.05) than in DDGSethanol, 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 DDGSbeverage may be as digestible as AA in DDGSethanol. The digestibility of AA in DDG is greater than in DDGS, which indicates that AA in the solubles have a lower digestibility than AA in DDG.