Review: protein value of distillers dried grains with solubles (DDGS) in animal nutrition as affected by the ethanol production process

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

This study aimed to determine the values of net energy (NE), digestible energy (DE) and metabolizable energy (ME) 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 (RD) or 800 g/kg RD + 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. Diets containing the HPDDG had greater DE and ME than those containing CBS and DDGS and greater DE than those containing the DDG (p < 0.05). HPDDG, DDG, CBS and DDGS showed 4498, 3419, 3029 and 3335 kcal/kg DE; 4366, 3305, 2934 and 3214 kcal/kg ME; and 2515, 1938, 1649 and 1725 kcal/kg NE, respectively. Pigs fed diets containing HPDDG and CBS showed greater nitrogen retention efficiency than pigs fed DDGS (p < 0.05). Pigs fed diets containing HPDDG had higher blood urea levels than pigs fed CBS and RD, 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.

Reconceptualization of the mechanism of thermal hydrolysis pretreatment to enhance the anaerobic conversion of sludge organic nitrogen: Decisive role of organic nitrogen occurrence

The occurrence state of organic nitrogen (ON) is the key to affect anaerobic biotransformation of sludge. ON in sludge was chemically classified as PA (easily accessible part), PB (moderately accessible) and PC (hardly accessible) according to the modified CNCPS method. The components of them were analyzed by PY-GCMS, and it was identified that PA was extracellular amino acids, peptides and proteins; PB was genetic material, cell wall peptidoglycans and intracellular proteins; PC was ON that cross-linked with complex macromolecules. The conversion characteristics of PA, PB and PC in sludge and their relationship with anaerobic digestion (AD) performance were investigated after thermal hydrolysis pretreatment (THP) at different temperatures (100-180 °C). With the increase of THP temperature, the hydrolysis of PA and the conversion of PB to PA were promoted. At 180-THP, part of PA was converted to PC due to thermochemical reactions. In the fast degradation stage of AD of ON (ON-fast), PA is the main component of degradation; while in the slow degradation stage (ON-slow), the degradation of ON is mainly dominated by PB. Therefore, THP can significantly increase the proportion of ON-fast and reduce the ON fraction in the digestate (ON-hard). Moreover, PA and PB, rather than PC, were identified as dominant in ON-hard with or without THP for the first time, overturning the traditional view (remaining ON after AD was that cross-linked with complex macromolecules). This is due to that PA and PB are the main ON that make up microbial cells. The findings upgraded our perspective on conversion of ON of sludge during AD and inspire the shifted focus from "degrading PC" to "PC accumulation" for later use, through targeted enhanced PA degradation.

Recent Progress in Distiller's Grains: Chemical Compositions and Biological Activities

Distiller's grains (DGs) are solid mixtures that remain after the production of alcoholic beverages. A large amount of DGs is produced each year during the brewing process. Currently, they are mostly used as a feedstock or substrate in the feed industry. However, the lack of a comprehensive understanding of the chemical composition of DGs is a major constraint on their further development and application for high-value-added usages. Some studies were published on the bioactive constituents of DGs in several different types of journals. Data were therefore collated to provide a comprehensive overview of these natural products. DGs are rich in phenols, phytosterols, and fatty acids, in addition to general lipid and protein constituents. These compounds and their related extracts possess diverse biological activities, including antioxidant, anti-inflammatory, and anti-hyperglycaemic effects. We hope that this review will provide research incentives for the further development and utilisation of DGs to develop high-value-added products.

Animal performance and meat quality characteristics from feedlot-finished steers fed increasing levels of wet distillers grain

One hundred forty-four steers were group-housed in 24 pens that were randomly assigned to one of four dietary treatments defined by the proportion of wet distiller grain plus solubles (WDGS; 0, 15, 30, or 45%) and fed for 84 d pre-slaughter. Animal performance was evaluated using the pen as the experimental unit. Whereas for carcass and meat quality characteristics, meat oxidative stability, and the consumer sensory quality of longissimus thoracis muscle one animal from each pen was randomly selected and used as the experimental unit. No differences (P > 0.05) were observed for subcutaneous fat thickness, rib eye area, marbling score or pH, color parameters, proximate composition, sarcomere length, Warner Bratzler shear force, and cooking loss. Feeding WDGS linearly increased total PUFA (P = 0.05), C18:2 n-6 (P = 0.004) proportions, and n-6/n-3 ratio (P < 0.01) but reduced C16:1 to C18:0 ratio (P < 0.01). Lipid oxidation was greater in beef from steers fed 30% and 45% WDGS (P = 0.05). Dietary WDGS linearly improved (P < 0.05) flavor and overall linking score in the consumer sensory panel.

Influence of dietary corn distillers' dried grains with solubles on nutrient digestibility, growth performance, and carcass traits in rabbits

Two experiments were performed to evaluate the digestibility and growth performance of New Zealand White rabbits fed corn distillers' dried grains with solubles (DDGS). For the digestibility trial, 20 rabbits were housed in metabolic cages. The animals were distributed in two treatments, T1 (control diet without inclusion of DDGS) and T2 (control diet + 300 g kg^-1 DDGS). For the growth performance trial, 100 rabbits (50 males and 50 females) were assigned in a factorial design 2 × 5 (2 gender × 5 inclusions of DDGS) and five replicates. The treatments were composed of diets with inclusions of 0, 60, 120, 180, and 240 g kg^-1 of DDGS. The rabbits were housed at 35 days old, and the experiment lasted 35 days. The DDGS showed high digestibility for protein (74.10%) and lipids (81.51%) and a high content of digestible energy (2979 kcal kg^-1). In the second trial, growth performance and carcass yield and organ relative weights were evaluated. There were no interactions between gender and DDGS inclusions (P > 0.05). A linear decrease was observed for feed intake (FI) for the period from days 35 to 50 (FI, P = 0.001) and FI and FCR from days 35 to 70 (FI, P = 0.004; FCR, P = 0.001) with the increasing levels of DDGS. Rabbits supplemented with 240 g kg^-1 had lower (P < 0.05) whole carcass yield (WCY) and carcass without head yield compared with the control rabbits. DDGS is highly digestible in rabbits, and when supplemented up to 240 g kg^-1 in diets, it improved FCR but reduced FI and WCY.

Evaluation of dehydrated corn silage as the primary forage for lactating dairy cows

The objective was to compare productivity of lactating dairy cows fed dehydrated corn silage with those fed whole-crop barley silage. Twelve multiparous Holstein cows in mid lactation were fed diets containing dehydrated corn silage (DCS) or barley silage with additional grain (BSHG) or without (BSLG) in a 3 × 3 Latin square design, with 21-d periods, balanced for carryover effects. The dietary starch content was similar for DCS and BSHG diets, and dietary forage content was similar for DCS and BSLG diets. Experimental diets did not affect dry matter intake, but cows fed DCS diet decreased milk yield compared with those fed barley silage regardless of the dietary starch content. Apparent total-tract digestibility of starch and crude protein was also lower for cows fed DCS compared with those fed barley silage, and milk urea N content was lowest for cows fed DCS diet, indicating that DCS likely had less protein degradation in the rumen than barley silage. Milk fat content and yield, energy-corrected milk yield, and feed efficiency were not different between cows fed BSHG and DCS diets, but higher for cows fed BSLG than those fed BSHG or DCS diet, which can be attributed to the difference in dietary starch content. Feeding DCS in place of barley silage did not improve productivity of lactating dairy cows in the current study, and further research is warranted to optimize its utilization in dairy diets.

Meat Quality and Muscle Tissue Proteome of Crossbred Bulls Finished under Feedlot Using Wet Distiller Grains By-Product

Wet distiller grains (WDG) are a corn by-product rich in protein and fiber that can be used in feedlot diets. This study evaluated F1 Angus-Nellore bulls fed on a control diet vs. WDG (n = 25/treatment). After a period of 129 days on these feeds, the animals were slaughtered and Longissimus thoracis samples were collected for both a meat quality evaluation and gel-based proteomic analyses. A greater ribeye area (99.47 cm²) and higher carcass weight (333.6 kg) (p < 0.05) were observed in the WDG-finished cattle compared to the control (80.7 cm²; 306.3 kg). Furthermore, there were differences (p < 0.05) in the intramuscular fat between the WDG and control animals (IMF = 2.77 vs. 4.19%), which led to a significant decrease (p < 0.05) in saturated fatty acids (FA). However, no differences (p > 0.10) were observed in terms of tenderness, evaluated using Warner–Bratzler shear force (WBSF). The proteomic and bioinformatic analyses revealed substantial changes in the biological processes, molecular functions, and cellular components of the WDG-finished cattle compared to the control. Proteins related to a myriad of interconnected pathways, such as contractile and structural pathways, energy metabolism, oxidative stress and cell redox homeostasis, and transport and signaling. In this experiment, the use of WDG supplementation influenced the protein expression of several proteins, some of which are known biomarkers of beef quality (tenderness and color), as well as the protein–protein interactions that can act as the origins of increases in muscle growth and reductions in IMF deposition. However, despite the effects on the proteome, the tenderness, evaluated by WBSF, and fatty acid profile were not compromised by WDG supplementation.

Evaluation of the Chemical Composition, Bioactive Substance, Gas Production, and Rumen Fermentation Parameters of Four Types of Distiller's Grains

Distiller’s grain is rich in natural active ingredients and can be used as an excellent antioxidant feed for goats. The current study aimed to assess the feeding value of four different types of distiller’s grains with an in vitro gas production trial. The chemical composition, total phenols, total anthocyanins, dry matter degradability, methane, hydrogen, and rumen fermentation parameters were evaluated. The results indicated that red distiller’s grain and glutinous rice distiller’s grain had higher (p < 0.05) levels of crude protein than the other two types. There were significantly (p < 0.05) higher concentrations of dry matter, ether extract, hemicellulose, and total carbohydrate in corn distiller’s grain than in the other three types of distiller’s grain. In addition, red distiller’s grain showed a higher (p < 0.05) gas production rate constant (c) and ruminal outflow rate, as well as higher (p < 0.05) concentrations of total phenol, total anthocyanins and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, than the other three types of distiller’s grains. In contrast, red distiller’s grain displayed the lowest (p < 0.05) immediately soluble fraction (a) and half the time of maximum gas production relative to the other samples. In particular, the levels of methane (%) in white distiller’s grain and glutinous rice distiller’s grain were greater (p < 0.05) than that in red distiller’s grain. Moreover, the ammonia nitrogen content in red distiller’s grain was greater (p < 0.05) than that in white distiller’s grain and corn distiller’s grain. In contrast, red distiller’s grain exhibited a lower (p < 0.05) level of ruminal fluid acetic acid relative to that found in white distiller’s grain and corn distiller’s grain. Taken together, the results showed that red distiller’s grain and glutinous rice distiller’s grain could be used as protein feed, red distiller’s grain had higher levels of total phenols and total anthocyanins and a high DPPH scavenging activity; corn distiller’s grain might be considered as an alternative energy source feed, and white distiller’s grain exhibited higher total gas production.

Corn distillers solubles as a novel bioresource of bioactive peptides with ACE and DPP IV inhibition activity: characterization, in silico evaluation, and molecular docking

This study aimed to investigate the biological potential of underutilized and low-value corn distillers solubles, containing a unique unexplored blend of heat-treated corn and yeast proteins, from the bioethanol industries, by bioinformatic and biochemical approaches. Protein hydrolysates were produced by applying four commercially accessible proteases, among which alcalase provided the best results in terms of yield, degree of hydrolysis, molecular weight, number of proteins, bioactive peptides, and deactivation against anti-angiotensin I-converting enzyme (ACE) and anti-dipeptidyl peptidase IV (DPP IV). The optimal conditions to produce anti-ACE and anti-DPP IV peptides were using alcalase for 10.82 h and an enzyme : substrate ratio of 7.90 (%w/w), with inhibition values for ACE and DPP IV of 98.76 ± 1.28% and 34.99 ± 1.44%, respectively. Corn (α-zein) and yeast (glyceraldehyde-3-phosphate dehydrogenase) proteins were mainly suitable, upon enzymolysis, for the release of bioactive peptides. The peptides DPANLPWG, FDFFDNIN, WNGPPGVF, and TPPFHLPPP inhibited ACE more effectively as verified with binding energies of -11.3, -11.6, -10.5, and -11.6 kcal mol^-1, respectively, as compared to captopril (-6.38 kcal mol^-1). Compared with the binding energy of sitagliptin (-8.6 kcal mol^-1), WNGPPGVF (-9.6 kcal mol^-1), WPLPPFG (-9.8 kcal mol^-1), LPPYLPS (-9.7 kcal mol^-1), TPPFHLPPP (-10.1 kcal mol^-1), and DPANLPWG peptides (-10.1 kcal mol^-1) had greater inhibition potential against DPP IV. The peptides impeded ACE and DPP IV majorly via hydrophobic and hydrogen linkage interactions. The key amino acids TYR⁵²³, GLU³⁸⁴, and HIS³⁵³ were bound to the catalytic sites of ACE and GLN⁵⁵³, GLU²⁰⁶, PHE³⁶⁴, VAL³⁰³, and THR³⁰⁴ were bound to the DPP IV enzyme. The PHs can be used as ingredients in the feed or food industries with possible health advantages.

Replacing cottonseed meal and sorghum with dried distillers` grains with solubles enhances the growth performance, carcass traits, and meat quality of feedlot lambs

We evaluated the impacts of substituting cottonseed meal (CSM) and sorghum grain (SG) with dried distillers` grains with solubles (DDGS) in lamb feedlot diets on the dry matter intake (DMI), the growth performance, blood serum analysis, feces phosphorus (P) and nitrogen (N), wool production and quality, carcass traits, adipose tissue fatty acid (FA) profiles, and sensory panel tests. For 72 d, Rambouillet wether lambs (n = 44, initial body weight, BW = 28.8 ± 3.3 kg) were individually fed ad libitum pelleted diets containing DDGS that replaced 0% (0DDGS), 25% (25DDGS), 50% (50DDGS), or 75% (75DDGS) of the CSM and SG in a completely randomized design trial. Linear and quadratic effects of DDGS levels on the response variables were analyzed. Treatment × day interactions (P < 0.001) were observed for BW and DMI. As the DDGS level was increased, DMI (from days 21 to 70), lamb BW (from days 56 to 70), average daily gain, blood urea nitrogen and P, and fecal P linearly increased (P ≤ 0.05). Fecal N quadratically increased (P = 0.01), but no effects were found for gain:feed, blood insulin-like growth factor-1, or calcium. No differences in wool production or most of the wool quality parameters were detected. Adipose tissue stearic acid linearly increased (P = 0.02), linoleic acid quadratically increased (P = 0.01), and oleic acid tended to quadratically decrease (P = 0.08) as the DDGS increased in the diets. Increasing the DDGS level in the diets quadratically increased the hot carcass weight (P = 0.02), backfat thickness (P = 0.04), and body wall thickness (P < 0.001) while having no impact on the longissimus muscle area. As the DDGS increased in the diet, juiciness, tenderness, and overall acceptability linearly increased (P ≤ 0.05), while having no effect on the cook-loss, flavor intensity, or off-flavor detectability. Replacing 50% of CSM and SG with DDGS improved growth performance and enhanced the carcass and meat quality.

Physicochemical characterisation of kafirins extracted from sorghum grain and dried distillers grain with solubles related to their biomaterial functionality

Kafirin, the hydrophobic prolamin storage protein in sorghum grain is enriched when the grain is used for bioethanol production to give dried distillers grain with solubles (DGGS) as a by-product. There is great interest in DDGS kafirin as a new source for biomaterials. There is however a lack of fundamental understanding of how the physicochemical properties of DDGS kafirin having been exposed to the high temperature conditions during ethanol production, compare to kafirin made directly from the grain. An understanding of these properties is required to catalyse the utilisation of DDGS kafirin for biomaterial applications. The aim of this study was to extract kafirin directly from sorghum grain and from DDGS derived from the same grain and, then perform a comparative investigation of the physicochemical properties of these kafirins in terms of: polypeptide profile by sodium-dodecyl sulphate polyacrylamide gel electrophoresis; secondary structure by Fourier transform infra-red spectroscopy and x-ray diffraction, self-assembly behaviour by small-angle x-ray scattering, surface morphology by scanning electron microscopy and surface chemical properties by energy dispersive x-ray spectroscopy. DDGS kafirin was found to have very similar polypeptide profile as grain kafirin but contained altered secondary structure with increased levels of β-sheets. The structure morphology showed surface fractals and surface elemental composition suggesting enhanced reactivity with possibility to endow interfacial wettability. These properties of DDGS kafirin may provide it with unique functionality and thus open up opportunities for it to be used as a novel food grade biomaterial.

A review on the use of dried distiller’s grains with solubles (DDGS) in aquaculture feeds

Distiller’s dried grains with soluble (DDGS) to replace fishmeal (FM) or other plant protein sources and its effects on an aquatic animal’s growth performance and health system is rarely discussed. In recent times FM use in aquafeed has been a problem for the aquaculture industry because of the depletion of fish resources in the ocean and the high cost of FM. For that reason, researchers are focusing on reducing the cost of aquafeed production by lowering the inclusion of FM in aquafeed. One of the low-cost alternative protein sources to replace FM is DDGS. The present review discusses the compilation of available literature review and other works on the use of DDGS to replace FM in aquafeed and how it improves the growth performance, immune health system, and disease resistance in an aquatic animal. It focuses on the production of DDGS, the nutritional composition of DDGS, the chemical and physical characteristics of DDGS, and the effects of the DDGS inclusion in aquafeed on the aquatic animal. Apart from improving the growth performance of the aquatic animal when included in aquafeed, it also helps improve the immune health system of the animal. It also helps boost the immune system of the aquatic animal to fight diseases and increase disease resistance when included in aquafeed. Furthermore, DDGS also contains some constituents like carotenoids that help improve the meat quality of the animal when included in aquafeed. The current review also discusses the management and use of technology to improve the aquaculture industry, educate farmers on reducing diseases during the culturing periods, and increase productivity and profit in a friendly environment.

Meat quality traits and feeding distillers grains to cattle: a review

Livestock management and meat production involve a series of steps that affect meat quality. Animal genetics, nutrition and diets, slaughter procedures and meat-preservation conditions are some of the parameters that should be controlled to maintain meat quality. In regard to animal nutrition and diets, novel ingredients are increasingly used, distillers grains (DG) being an example. DG are obtained as a co-product from bioethanol production and comprise the fat, protein, fibre and micronutrient portion of the grains. Many papers have studied the inclusion of DG in finishing diets and their effect on growth performance and meat characteristics, but a review on the effects on meat quality is needed. Feeding with DG influences beef colour; nevertheless, a relationship between the level of inclusion and colour development has not been established yet. In addition, feeding DG-inclusion diets sometimes increases meat discoloration during retail display. Also, the composition of fatty acids is modified since total polyunsaturated fatty acid content in meat increases with the inclusion of DG in finishing diets. This increment in polyunsaturated fatty acid content is likely to contribute to lipid oxidation processes and might be related to meat discoloration due to myoglobin oxidation. However, meat tenderness has not been modified in most of the cases. This review focused on recent studies on DG inclusion, animal performance and meat quality. Key points that need further research are also identified and discussed.

Purification of Polyphenols from Distiller's Grains by Macroporous Resin and Analysis of the Polyphenolic Components

We aimed to purify polyphenols from distiller’s grain extract using macroporous resins and to identify its polyphenolic components. The influence of operational parameters on purification efficiency was investigated. The polyphenolic composition was analyzed by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) and then quantified by UPLC-MS using authenticated standards. The results showed that the optimal purifying conditions were D101 resin with a dosage of 3 g, four hours adsorption, three hours desorption time, and 60% ethanol as the eluent, producing the highest purification rate of 51%. The purified distiller’s grain extract exhibited stronger antioxidant activity than the unpurified extracts, which was assessed using DPPH and ABTS methods (IC₅₀ DPPH = 34.03 and 16.21 μg/mL, respectively; IC₅₀ ABTS = 20.31 and 5.73 μg/mL, respectively). UPLC-MS results indicated that (−)-epicatechin is the major compound found in distiller’s grain extract which was quantified as 562.7 μg/g extract, followed by ferulic acid (518.2 μg/g), p-hydroxybenzoic acid (417.7 μg/g), caffeic acid (217.1 μg/g), syringic acid (158.0 μg/g) and quercetin (147.8 μg/g). Two compounds, vanillic acid (66.5 μg/g) and gallic acid (41.4 μg/g), were found in lower concentrations. The findings of this study suggest that purification of polyphenolic compounds from distiller’s grain by macroporous resins is feasible, providing a new and effective method for the secondary use of distiller’s grain resources.