Digestibility of dietary fiber in distillers coproducts fed to growing pigs

P. E. Urriola,* G. C. Shurson,† and H. H. Stein*

The objective of this work was to measure the apparent ileal digestibility (AID) and the apparent total tract digestibility (ATTD) of dietary fiber in different sources of distillers dried grains with solubles (DDGS) and to calculate hindgut fermentation of dietary fiber in DDGS fed to growing pigs. Diets, ileal digesta, and fecal samples from pigs fed corn or diets containing 1 of 28 sources of distillers coproducts were analyzed for fiber. Of the 28 sources of coproducts, 24 sources were corn DDGS (C-DDGS), 1 source was sorghum DDGS (S-DDGS), 1 source was DDGS from a blend of sorghum and corn (SC-DDGS), 1 source was C-DDGS from beverage production (DDGSbeverage), and a source of corn distillers dried grain (DDG) was also included in the experiment. Total dietary fiber (TDF) and DM were analyzed in all DDGS sources, ileal digesta, and fecal samples. Hindgut fermentation was calculated by subtracting values for AID from values for ATTD. In 10 sources of DDGS and in ileal and fecal samples from pigs fed those sources, crude fiber, ADF, NDF, insoluble dietary fiber (IDF), and soluble dietary fiber (SDF) were also determined. Concentrations of CP, ether extract, and ash were also analyzed in these samples, and concentrations of organic residue (OR) were calculated by subtracting the concentration of CP, ether extract, and water from OM. The AID and the ATTD of TDF differed (P < 0.01) among sources of C-DDGS. The average AID of TDF in 10 sources of C-DDGS (21.5%) was not different (P > 0.05) from the AID of TDF in corn (16.5%), but the ATTD and the hindgut fermentation of TDF in the 10 sources of C-DDGS (44.5 and 23.0%, respectively) were greater (P < 0.05) than in corn (23.1 and 6.6%, respectively). The AID of crude fiber, NDF, IDF, SDF, and TDF were not different between C-DDGS and S-DDGS, but the AID of ADF was greater (P < 0.01) in S-DDGS (57.4%) than in C-DDGS (36.8%). The ATTD of OR in S-DDGS (72.5%) and SC-DDGS (68.4%) were less (P < 0.05) than in C-DDGS (77.1%), but the ATTD of ADF, NDF, IDF, SDF, and TDF were not different among the 3 sources of DDGS. The AID, ATTD, and hindgut fermentation of TDF were not different between DDGS from an ethanol plant and DDGS from a beverage plant. The average AID, ATTD, and hindgut fermentation of TDF in the 24 sources of C-DDGS were 23.0, 47.3, and 24.4%, respectively. It is concluded that the AID and ATTD of fiber differ among sources of DDGS and those differences may contribute to differences in the digestibility of energy in DDGS.

Key words: dietary fiber, digestibility, distillers coproduct, distillers dried grains with solubles, pig