Development of a novel value-added distillers dried grains with solubles: Effects on amino acid and energy digestibility in pigs

Ethanol production from corn in the U.S. is increasing at an annual rate of 30% resulting in large increases in the availability of the resulting byproduct, distillers dried grains with solubles (DDGS). A majority of DDGS is fed to ruminant animals due to its high fiber content and relatively low amino acid digestibility. However, DDGS production will outgrow its demand as a ruminant animal feed. The first objective of this research was to evaluate the differences in amino acid and energy digestibility among various sources of DDGS available on the market that varied in the degree of lightness or darkness due to differences in drying temperatures and times. This was accomplished by using the true ileal amino acid digestibility technique in growing swine using a low-protein casein diet to determine endogenous amino acid losses. The results demonstrated that essential amino acid digestibility was lower (P < 0.05) in sources 1 and 5, the two sources darkest in color. However, source 5, the darkest colored DDGS, had a 10% lower (P < 0.05) overall essential amino acid digestibility and a 15% lower (P < 0.05) lysine digestibility than the other four sources. Lysine digestibility appeared to be reduced to a greater extent by the degree of darkness of DDGS more so than the other essential amino acids. These results suggest that darker DDGS have lower (P < 0.05) lysine and essential amino acid digestibilities than lighter colored DDGS sources.; The fiber portion of DDGS is primarily cellulose and hemicelluloses that have a low digestibility in nonruminants. The hydrolysis of these indigestible components using physical, chemical and enzymatic processes may improve the availability of nutrients when fed to pigs. The second objective of this research was to produce various value-added DDGS with the goal of breaking down as much fiber as possible to improve nutrient digestibility in the pig. The four value-added products produced were DDGS steeped with (+S/+E) or without (+S/-E) enzymes or DDGS that had been acid pretreated followed by steeping with (+A/+S/+E) or without (+A/+S/-E) enzymes. Steeping with enzymes resulted in a 30--40% reduction in neutral and acid detergent fiber (NDF and ADF) content while acid pretreatments followed by steeping with enzymes reduced NDF and ADF contents by 95%. (Abstract shortened by UMI.)...