This has direct economic implications. A DDGS lot that appears attractive on crude protein price alone may be less competitive once its lower energy value is accounted for in the complete diet.

Oil extraction can also influence amino acid quality. Research has shown that low-oil DDGS may differ from higher-oil sources in the apparent digestibility of amino acids including lysine, methionine, threonine, tryptophan and arginine.

Higher oil is not automatically better

Although higher-fat DDGS can contribute more energy, greater oil content also changes how the ingredient behaves during manufacturing and storage.

Higher residual fat can influence:

• Pellet quality and durability
• Ingredient flowability
• Dietary fat balancing
• Oxidative stability during storage
• Handling and shelf-life considerations

Drying conditions can determine protein quality

Drying is essential to reduce moisture and stabilize DDGS for transport and storage. However, excessive thermal exposure can reduce the biological value of the protein.

DDGS contains both protein and residual reducing sugars. Under excessive heat, these compounds can participate in Maillard reactions, which are particularly important for lysine because its reactive amino group is highly susceptible to heat damage.

The result can be a DDGS sample that still tests well for crude protein but supplies less usable lysine to the bird. Poultry research has repeatedly identified lysine as one of the amino acids most vulnerable to heat damage in DDGS.

Why lysine deserves special attention

Corn is already relatively low in lysine compared with its total protein content, so heat damage can further magnify this limitation in DDGS.

Published poultry work reports substantial variation in lysine digestibility among DDGS sources. Reviews have noted digestibility values around 50–65% in broilers for some DDGS products, compared with much higher values in soybean meal. :contentReference[oaicite:3]{index=3}

This is particularly relevant in starter diets, where amino acid density and digestibility are critical and marginal lysine deficiencies can quickly affect growth and feed efficiency.

Can color reveal heat damage?

Darker DDGS has historically been associated with excessive drying and greater Maillard reaction activity. Research in poultry has shown that some of the darkest DDGS samples can have lower lysine availability and lower metabolizable energy.

However, color should only be used as a warning signal rather than a definitive quality test. Grain type, solubles addition and processing conditions can all affect appearance independently of protein damage.

Where possible, nutritionists should rely on more direct measurements such as:

• Reactive lysine
• Standardized ileal digestible amino acids
• Analyzed crude fat
• AMEn or validated energy estimates
• Moisture and fiber
• Near-infrared spectroscopy where properly calibrated

Source variability matters as much as composition

DDGS composition varies because ethanol plants do not all use the same processing system. Differences may arise from:

Recent broiler work continues to demonstrate that different DDGS processors can produce ingredients with different AMEn values and standardized ileal amino acid digestibility, reinforcing the need for source-specific evaluation.

Formulate from analyzed values, not averages

Because variability can be substantial, poultry feed mills can reduce risk by building DDGS quality control into routine procurement.

Best practice includes:

• Regular laboratory analysis of incoming DDGS for protein, fat, fiber and moisture.
• Source-specific formulation rather than relying exclusively on generic matrix values.
• Using digestible amino acid values where available.
• Monitoring reactive lysine or other heat-damage indicators for suspect lots.
• Adjusting energy values according to residual oil content.
• Maintaining supplier and processing-history records.

Mycotoxin risk also needs attention

DDGS can also carry mycotoxins that were present in the original grain. Because starch is removed during fermentation, other grain components become concentrated in the remaining co-product.

For feed mills using significant DDGS volumes, routine mycotoxin surveillance should therefore form part of the same supplier-specific quality program used for energy and amino acid evaluation.

How much DDGS can poultry diets use?

DDGS can be incorporated successfully into broiler and layer diets, but useful inclusion rates depend heavily on ingredient quality, age of the bird and how accurately energy and amino acid values are represented in the formulation.

Research suggests that higher inclusion rates can be more challenging, particularly when lysine digestibility or energy values are overestimated. Some poultry studies have reported impaired broiler performance when DDGS levels move beyond approximately 15%, reinforcing the importance of formulation accuracy at higher inclusion rates.

This does not mean there is one universal maximum inclusion rate. Instead, it highlights that the acceptable level depends on the quality of the DDGS and the precision of the overall diet formulation.

Processing history can matter more than crude protein

For integrators and feed mills, one of the most important lessons is that crude protein alone does not determine the economic value of DDGS.

A product with slightly lower crude protein but higher usable energy, more reactive lysine and less thermal damage may deliver more value than a darker, heavily de-oiled product with a superficially attractive protein concentration.

Outlook

DDGS will remain an important ingredient for poultry producers seeking alternative sources of protein, energy and phosphorus. But the ethanol sector itself continues to evolve, particularly as more plants extract corn oil for use in biodiesel and other markets.

That means the nutritional profile of DDGS is also changing.

Nutritionists who track residual oil, digestible amino acids, heat damage and source-specific variability will be better positioned to capture the economic value of DDGS while avoiding hidden formulation errors.