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A total of eleven growing barrows (initial BW = 44.6 ± 6.5 kg) were surgically fitted with a T-cannula in the distal ileum and allotted to 11 diets and 8 periods. A total of eleven experimental diets were formulated. Ten diets based on each source of DDGS and one N-free diet. The N-free diet was used to measure basal ileal endogenous losses of N and AA. Therefore, one diet contained 66.7% S-DDGS, 1 diet contained 66.7% SC-DDGS, 8 diets contained 66.7% C-DDGS, and 1 diet was N-free. Chromic oxide (0.3%) was used in all diets as an indigestible marker. The direct procedure was used to measure apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of CP and AA in the 10 sources of DDGS.
The AID of Lys was not different among S-DDGS, SC-DDGS, and C-DDGS. The mean SID of CP, Arg, and Lys in C-DDGS were not different from values obtained in S-DDGS and SC-DDGS. The SID of Trp in S-DDGS (72.0%) was greater (P < 0.01) than in C-DDGS (64.9%), but there was no difference between C-DDGS and SC-DDGS (62.4%). The SID of CP and all AA were different among the 8 sources of C-DDGS (P < 0.01). Among the indispensable AA, Lys had the greatest variation and the SID ranged from 55.7 to 68.7%. The concentration of total and digestible AA was highly correlated (r2) for Arg (0.88), Ile (0.85), Leu (0.82), Phe (0.84), and Trp (0.84), but reduced r2 values were observed for Lys (0.66) and Thr (0.39). A low correlation between the concentration and digestibility of AA indicates that it is desirable to develop in vitro procedures to predict digestible AA concentration in DDGS.
It is concluded the SID values for CP and Lys in S-DDGS and SC-DDGS are within the range of values obtained in C-DDGS, but for many other AA, SID values in S-DDGS and in SC-DDGS are less than in C-DDGS.
PE Urriola, D Hoehler, C Pedersen, HH Stein, and GC Shurson. 2009. Journal of Animal Science, 87:2574–2580.
