The ethanol industry is now extracting much of the corn oil in DDGS. This changes the nutrient value of DDGS when used as a feed ingredient but the exact effects have not been determined.

Dr Bill Dozier and Dr Joe Hess at Auburn University recently completed a research project funded by the USPOULTRY Foundation in which they determined the effects of removing the oil from DDGS on the energy content and amino acid digestibility in broilers.

They documented a significant decrease in energy content and were able to determine which amino acids were affected by oil removal. These results will allow rations to be more precisely formulated using DDGS from which the corn oil has been removed.

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 per cent crude protein (CP), 12 per cent ether extract (EE) and 44 per cent neutral detergent fibre (NDF).

With the ethanol industry seeking alternative 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 per cent to six per cent EE, while in contrast, concentrations of other nutrients in the resultant reduced-oil DDGS are increased.

The objectives of this research were to:

1. determine apparent metabolisable energy (AMEn) and amino acid digestibility of three 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 amino acid values determined from Objective 1.

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

In Experiment 2, apparent amino acid digestibility was determined feeding either L-DDGS, M-DDGS or H-DDGS.

Apparent amino acid digestibility coefficients were negatively affected by oil extraction for methionine, lysine, threonine, tryptophan and arginine. Conversely, no differences in apparent amino acid digestibility coefficients were seen for isoleucine, leucine and valine. These results indicated that L-DDGS had lower apparent amino acid 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 3, diets were formulated to contain L-DDGS, M-DDGS and H-DDGS at moderate (5, 7 and 9 per cent) and high (8, 10 and 12 per cent) 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.

In Experiment 4, diets were formulated to contain L-DDGS, M-DDGS, and H-DDGS at moderate (5, 7, 9 and 11 per cent) and high (8, 10, 12 and 14 per cent) inclusion rates of DDGS and fed to male broilers from one to 49 days of age. Neither DDGS source or inclusion rate affected cumulative performance nor parts yield.

In general, these data indicated acceptable performance can be obtained with deoiled DDGS if diets are formulated to the actual nutrient values of DDGS. Using an L-DDGS source can provide adequate performance but may increase diet cost because of its lower energy contribution.

October 2014