The objective of this project was to assess effects of pretreatment methods (chemical, enzymatic, and mechanical) on the digestibility of energy in DDGS. Combinations of different methods were investigated using in vitro models. The in vitro treatments investigated were: sodium hydroxide, ammonium hydroxide, hydrochloric acid and two types of enzyme, one a cellulase/xylanase mix and the other an enzyme complex containing a wide range of carbohydrases, designed to break down hemicellulose in biomass. The parameters considered for the in vitro tests were acid and neutral detergent fiber (ADF, NDF) as well as total dietary fiber (TDF) to get the amount of digestible fiber, cellulose and hemicellulose remaining in the DDGS after treatment, as well as lysine, used as an indicator of digestibility. The most promising methods from the in vitro study were then used in an in vivo experiment to determine if the improvements observed in vitro also resulted in improvements in energy digestibility of DDGS when fed to pigs.

The in vitro studies showed that the sodium hydroxide and enzyme treatments were significantly different in fiber content and the enzyme treatments were also higher in lysine than the control, therefore these were selected for the in vivo study. In addition, two more treatments, calcium oxide and mechanical extrusion were tested in vivo.

The animal studies showed that the cellulase was effective in improving the ME of DDGS. In contrast, addition of an enzyme mixture, extrusion, or chemical treatments of DDGS did not consistently improve the ATTD of the ingredient.
For more information, please contact Dr. Sabrina Trupia (email: or Dr. Hans Stein (email: