Datasheet: Corn DDGS

Introduction

Corn distiller's dried grains with solubles (DDGS) is the co-product derived from the process of producing ethanol from corn kernels.

During the fermentation process, most of the corn starch is converted to ethanol and carbon dioxide, concentrating the remaining nutrients (protein, fat, vitamins, and minerals) in the DDGS. This results in higher nutrient density compared to the original corn grain.

This co-product is characterized by its high protein content, typically around 27% (although there are concentrates that reach 40% CP), and its significant energy value.

This high protein content makes it an attractive ingredient as a protein source for swine. However, its amino acid profile can be limiting in some essential amino acids, especially lysine, threonine, and tryptophan. In addition, the availability of lysine can be reduced due to Maillard reactions caused by the heating that occurs during the production process (cooking process to hydrolyze starch into glucose and thus facilitate the fermentation of sugars to ethanol and CO₂).

Therefore, protein quality can vary significantly between different batches of DDGS due to variations in the production process and the raw material used.

It also contains notable amounts of fat, fiber, and easily digestible carbohydrates, which make it an interesting ingredient for swine feed.

It should be noted that most of the fibrous fraction is insoluble, ranging from approximately 31.8% to 37.3%, while the soluble fiber content is generally less than 2%. This high proportion of insoluble fiber can reduce the digestibility of the diet, which is basically linked to the content of non-starch polysaccharides: Cellulose 8-12%, Hemicellulose 12-25% (with arabinoxylans contributing 10-20% within this group), Arabinoxylans 10-20%, and Beta-glucans: 1-3%.

The variation in these fractions depends basically on the corn variety, the growing conditions, and the distillation process. Non-starch polysaccharides in corn DDGS can play an important role in intestinal health and microbiota in swine, however, we must consider the proper balance between the benefits and functionality of fermentation and production of short-chain fatty acids (SCFA) and the possible negative effects on digestion and nutrient absorption (viscosity and interference with absorption).

The physical structure of the fiber may trap part of the fat, limiting its accessibility to digestive enzymes and further contributing to the lower energy content available for absorption.

Fermentation can lead to the production of beneficial metabolites such as short peptides and other compounds that can improve the nutritional value of DDGS. These metabolites can have positive effects on pig health and performance.

Finally, the starch fermentation process contributes to the concentration of nutrients, compounds, and molecules that have not been degraded by this process. Mycotoxins, which are small and stable molecules, are not destroyed or significantly degraded in this process. Common mycotoxins that can be found in corn DDGS include aflatoxins, fumonisins, zearalenone, and trichothecenes (such as DON or vomitoxin), and are directly related to the original quality of the corn used. Therefore, it is essential to implement quality control measures to detect contaminants such as mycotoxins and to ensure compliance with safety standards for these types of ingredients.

Comparative study of nutritional values

The systems used in the comparison are FEDNA (Spain), CVB (the Netherlands), INRA (France), NRC (USA), and ROSTAGNO (Brazil).

¹Among the evaluation systems studied, CVB considers only one category for corn DDGS. However, INRA and BRAZIL consider 2 categories differentiated basically by crude protein concentration. FEDNA and NRC consider a wider range of categories beyond protein content, considering fat content and residual unfermented starch.

Corn DDGS is usually the most commonly available protein ingredient in swine feed mills. It comes either in the form of coarse meal directly from the fermentation and distillery process or compressed into coarse pellets for ease of transport and processing.

Its availability very much determines its inclusion in swine diets, and the ingredient tends to be mainly used in growing and finishing formulas. Although the nutritional profile is not a limiting factor for the rest of the physiological phases, given its high variability between batches and processing plants, regardless of quality control, it is usually less used in breeding sow and nursery diets due to the reluctance associated with the content of potentially challenging agents for the intestinal mucosa, liver, and reproductive tract (mainly anti-nutritional factors and mycotoxins).

The level of inclusion is highly variable between countries and feed types and is closely linked to the fermentation and distillery industry, as well as the volumes produced, which are basically subject to the price and demand of ethanol, as well as to domestic regulations and international trade policies.

The United States is the main producer of DDGS, but South America is also significant. They are the primary consumers and control the exports to Europe and Asia where the fermentation industry is small, and they therefore depend on the import and trade of corn DDGS.

Corn DDGS are basically a protein ingredient but their fat and fiber content is not negligible, and they can have interesting nutritional value and functionality in the formulation of swine feed.

The average protein content in corn DDGS produced by traditional methods is around 27.6%±1.42, although it presents high variability (CV>5%). However, systems subject to typical producing countries (NRC and BRAZIL) consider a differentiated category with a much higher protein content, reaching values between 42 and 45%. Although less common, these protein concentrations are obtained with technological variants during processing and fermentation, including fractionation, which consists of incorporating technologies for fiber separation, protein fractionation, and elimination of non-protein components, allowing further concentration of the protein fraction. Protein content is inversely proportional to starch and residual sugar content (R²=0.45). As it is a protein ingredient, >30% of the DM is explained by protein. Protein content also determines the energy value of the ingredient ME (3137±355 kcal/kg; CV=11.3%) and NE (2223±182 kcal/kg; CV=8.2%), with coefficients of determination of R²=0.51 and R²=0.35, respectively.

The fat content (9.2±3.24 %; CV=38.5%) is highly variable and is the result of the concentration and non-degradation of the lipid fraction during the fermentation process. Although the ethereal extract is not determinant in the final energy value, its residual content contributes positively (R²=0.23) if we do not consider the observations corresponding to high protein content.

The average crude fiber value is also a result of the non-degradation of this fraction during the fermentation and distillation process. The average crude fiber content is 7.4%±0.91, however, the variability is high (CV>10%), although a direct relationship applicable by technological processing or implementation of fragmentation methods is not observed since the values considered for high protein DDGS by NRC and BRAZIL are 7.3 and 6.9%, respectively.

The range of dry matter proposed by the different evaluation systems is very stable across all systems, with very little variation among them (89.9%±0.99; CV=1.10%). However, the content of starch and sugars (mainly pentoses and hexoses, including galactoses) is much more variable and subject to processing in the case of starch (6.36%±3.24; CV=50.9%), and to the nature of the variety or growing conditions in the case of sugars (1.6%±0.58; CV=36.2%), which can also condition the formulation process or the result of the formulation if this variability is not taken into account.

The variation and response observed to protein content is what determines the AA profile associated with the nature of the corn grain used and the processing (presence of starch and residual sugars). Variable concentrations of lysine (2.85%±0.27; CV=9.40%), threonine (3.64%±0.11; CV=3.12%), and tryptophan (0.69%±0.10; CV=14.2%) are present. A variability not directly explained by variability in protein content. Sulfur amino acids (3.81%±0.77; CV=20.9%), present the highest variability.

The protein and lysine digestibility coefficient ranges between 50-55% and is very similar across the evaluation systems studied. However, processing and residual starch content are inversely proportional to AA digestibility (R²=0.3 to 0.50, respectively between lysine and tryptophan).

Corn DDGS present slightly higher calcium content (0.04%%±0.020; CV>60%) and higher total phosphorus (0.67%%±0.18; CV>25%) compared to corn grain (0.02-0.03% Ca and 0.25-0.30% P), and have similar Ca and slightly higher in P compared to traditional cereals such as barley (0.05-0.07% Ca and 0.5-0.40% P), wheat (0.04-0.05% Ca and 0.35-0.40% P), and rye (0.04-0.06% Ca and 0.35-0.40% P).

Recent findings

1. Brazilian Corn Ethanol Coproducts for Pigs: Feeding Value and Blood Parameters.

The present study aimed to determine the values of net energy, digestible energy, metabolizable energy, and digestibility coefficients of corn ethanol coproducts produced in Brazil and their effects on the nitrogen balance and blood parameters of pigs.

Ten barrows were housed in metabolic study cages for total collection and fed a reference diet or 800 g/kg reference diet + 200 g/kg of a coproduct of corn ethanol. Distiller's dried grains with solubles (DDGS), corn bran with solubles (CBS), distiller's dried grains (DDG), and high-protein distiller's dried grain (HPDDG) were evaluated. The experimental design was randomized blocks with three repetitions per period, totaling six repetitions per diet.

It was concluded that pigs fed diets containing HPDDG had higher blood urea levels than pigs fed CBS and reference diet, while triglyceride levels in animals that received the CBS diet were greater than those in animals that received all other diets. The HPDDG had the highest energy levels and the best digestibility coefficients. The chemical composition of coproducts influences the nitrogen balance and circulating levels of urea and triglycerides in pigs.

2. Effects of Feeding Corn Distillers Dried Grains with Solubles on Muscle Quality Traits and Lipidomics Profiling of Finishing Pigs.

The present study investigated the effects of adding corn distiller's dried grains with solubles (DDGS) to the diet on the meat quality, chemical composition, fatty acid composition, and lipidomics profiling in the longissimus thoracis of finishing pigs.

Twenty-four healthy crossbred pigs (average body weight 61.23 ± 3.25 kg) were randomly divided into two groups with three replicates per group and four pigs per pen. The control group was fed a basal diet, and the DDGS group was fed an experimental diet with 30% DDGS.

The study concluded that, feeding DDGS affects the meat quality and fatty acid composition and may affect the lipid profile in the longissimus thoracis of finishing pigs by regulating lipid metabolism.

3. Performance response of increasing the standardized ileal digestible tryptophan:lysine ratio in diets containing 40% dried distiller grains with solubles.

The present work studied the impact of supplementing corn by-products from the ethanol industry, such as dried distiller's grains with solubles (DDGS), since they can be an economical feed ingredient in pig rations. However, when pigs are fed high dietary levels of DDGS, their growth performance can decrease. This decrease may be a result of the protein composition of the diet and more specifically the dietary amino acid composition.

In the present study, the amino acid, tryptophan, was incrementally increased in diets containing 40% DDGS. The increase in dietary tryptophan resulted in increased pig feed intake and growth rate of pigs. These results suggest that increasing the dietary tryptophan level can help mitigate a portion of the decreased growth performance seen by pigs consuming higher dietary levels of DDGS. However, feeding 40% DDGS still resulted in a lower cumulative growth rate compared to a standard corn soybean meal diet.

It is concluded that other nutritional strategies are required to restore the growth performance of pigs fed 40% DDGS relative to a standard corn-soybean meal diet, but increasing dietary tryptophan can help to partially restore growth performance.

4. Environmental impacts of eco-nutrition swine feeding programs in spatially explicit geographic regions of the United States.

Very few studies have been conducted to determine the differences in environmental impacts based on the diet composition of growing-finishing swine feeding programs across major pork production regions in the United States. Therefore, the objective of this study was to determine and compare greenhouse gas emissions, water consumption, land use, as well as nitrogen (N), phosphorus (P), and carbon (C) balance of five diet formulation strategies and feeding programs for growing-finishing pigs (25–130 kg body weight) in the three spatially explicit U.S. pork production regions.

The corn dried distiller's grains with solubles (DDGS), food waste, and low protein-synthetic amino acid diets had less estimated N and P excretion compared with corn-soybean meal diets, and the addition of phytase to corn-soybean meal diets resulted in the greatest reduction in P excretion among feeding programs. Adding food waste to diets resulted in the least overall greenhouse gas emissions, water consumption, and land use compared with all other feeding programs, and land use was less for the DDGS and low protein-synthetic amino acid feeding programs than corn-soybean meal and phytase feeding programs.

References

FAOSTAT: http://www.fao.org/faostat/es/#data/QC

http://www.mapama.gob.es/es/agricultura/temas/producciones-agricolas/cultivos-herbaceos/cereales/

FEDNA: http://www.fundacionfedna.org/

Rostagno, H,S, 2017, TABLAS BRASILEÑAS PARA AVES Y CERDOS, Composición de Alimentos y Requerimientos Nutricionales, 4° Ed.

Sauvant D, Perez, J, y Tran G, 2004, Tablas de composición y de valor nutritivo de las materias primas destinadas a los animales de interés ganadero, INRA.

https://www.indexmundi.com/agriculture/