Evaluation Of Deoiled Distiller's Dried Grains With Solubles

By W. A. Dozier, III and J. B. Hess

The ethanol industry produces a variety of co-products, ranging from dehydrated corn germ meal to corn bran, with high-oil distiller's dried grains with solubles (DDGS) being approximately 31 percent crude protein (CP), 12 percent ether extract (EE), and 44 percent neutral detergent fiber (NDF). With the ethanol industry seeking alternate profit streams from ethanol plants and the biodiesel industry seeking alternatives to high-priced soybean oil, one potential additional product is corn oil extracted from existing ethanol plants. In extracting the oil in DDGS, crude fat levels can drop from approximately 12 percent to 6 percent EE, while in contrast, concentrations of other nutrients in the resultant reduced-oil DDGS are increased.

The objectives were to: 1) determine metabolizable energy (AMEn) and amino acid (AA) digestibility of 3 sources of DDGS and 2) examine growth and meat yield responses of broilers fed diets consisting of three sources of DDGS fed to different inclusion levels from one to 35 day and one to 49 day of age. Diets were formulated using AMEn and digestible AA values determined from Objective 1.

In experiment one, AMEn was determined as 1,975, 2,644, and 3,137 kcal/kg for low-oil DDGS (L-DDGS), medium-oil DDGS (M-DDGS), and high-oil DDGS (H-DDGS), respectively.

In experiment two, apparent AA digestibility was determined feeding either L-DDGS, M-DDGS, or H-DDGS. Apparent AA digestibility coefficients were negatively affected by oil extraction for methionine, lysine, threonine, tryptophan and arginine. Conversely, no differences in apparent AA digestibility coefficients were seen for isoleucine, leucine and valine. These results indicated that L-DDGS had lower apparent AA coefficients for methionine, lysine, threonine, tryptophan and arginine compared with H-DDGS and that this should be considered when formulating diets using deoiled DDGS.

In experiment three, diets were formulated to contain L-DDGS, M-DDGS, and H-DDGS at moderate (5, 7, and 9 percent) and high (8, 10, and 12 percent) inclusion rates of DDGS and fed to male broilers from one to 35 days of age. Broilers receiving diets with a higher inclusion of DDGS had lower body weight gains and poorer feed conversion ratios. Oil content of the DDGS source did not affect live performance. Abdominal fat yield was reduced and breast yield was increased for broilers receiving the H-DDGS source at moderate inclusion levels.