Sources Of Distillers Dried Grains With Solubles Research Articles

Standardized Ileal Digestibility of Reactive Lysine in Distillers Dried Grains with Solubles Fed to Growing Pigs

The Maillard reaction can occur during the production of distillers dried grains with solubles (DDGS) as a result of the addition of condensed solubles to the wet distillers cake during drying. The Maillard reaction can lead to the formation of unavailable or unreactive lysine as a result of binding of reducing sugars to the epsilon-NH(2) group of Lys. The Lys that remains unbound is called reactive Lys. The conventional procedure to measure the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of total Lys in DDGS may overestimate the amount of digestible Lys in DDGS because this procedure does not discount the unreactive Lys in DDGS, although only the reactive Lys is available for use by animals. By measuring the ileal digestibility of only the reactive Lys, it is expected that estimation of the amount of bioavailable Lys in DDGS will be more accurate. The objective of this experiment, therefore, was to test the hypothesis that the concentrations of AID and SID of reactive Lys are lower than the concentrations of AID and SID of total Lys in DDGS. Twelve DDGS sources, diets containing each of these 12 DDGS sources, and ileal digesta from pigs fed these diets were obtained from two previous experiments. Samples were guanidinated with O-methylisourea and analyzed for the concentration of homoarginine. It was assumed that only the reactive Lys, but not the unreactive Lys, would be transformed to homoarginine. This procedure, therefore, allows the separate measurement of reactive and unreactive Lys in DDGS-containing diets and ileal digesta. Subsequently, the ileal digestibility of reactive Lys can be calculated. The AID and SID of reactive Lys (percent) and the concentration of apparent ileal and standardized ileal digestible reactive Lys (g/kg) were then calculated and compared with the previously calculated values for total Lys. Results showed that only 76% of the total Lys in DDGS is reactive. The AID and SID of reactive Lys in DDGS (average = 60.1 and 66.9%, respectively) were similar to the AID and SID of total Lys (60.9 and 66.5%, respectively). When calculated as grams per kilogram, the concentration of standardized ileal digestible reactive Lys (3.9 g/kg) was lower (P < 0.05) than the concentration of standardized ileal digestible total Lys (5.1 g/kg). Thus, 24% of the concentration of standardized ileal digestible total Lys that was calculated using the conventional ileal AA digestibility procedure was unreactive Lys. The implication of these results is that the conventional AA digestibility procedure overestimates the concentration of digestible Lys in DDGS, and measurement of the concentration of digestible reactive Lys may more accurately estimate the amount of Lys in DDGS that is bioavailable to the pig.

Application of the Reactive Lysine Procedure To Estimate Lysine Digestibility in Distillers Dried Grains with Solubles Fed to Growing Pigs

Two experiments were conducted to measure the reactive Lys concentration in corn distillers dried grains with solubles (DDGS). In expt 1, reactive Lys was measured in 33 sources of DDGS using two procedures: the homoarginine procedure and the furosine procedure. The concentration of reactive Lys in DDGS was then correlated with the concentration of standardized ileal digestible (SID) Lys in DDGS fed to growing pigs. In expt 2, a factorial experiment was conducted using four ratios of condensed distillers solubles (CDS) and wet distillers grain (WDG). The ratios (wt/wt) of CDS to WDG were 0:100, 20:80, 40:60, and 100:0, and four subsamples from each combination were freeze-dried or oven-dried at 50, 75, or 100 degrees C. The dried samples were designated DDG, DDGS 20, DDGS 40, and CDS, respectively. All subsamples were analyzed for total Lys and for reactive Lys using the homoarginine procedure. Results of expt 1 showed that only 74.1% of total Lys was reactive if measured by the homoarginine procedure and 83.5% was reactive if measured by the furosine procedure. The concentration of SID Lys in DDGS was correlated with the concentration of reactive Lys measured by the homoarginine procedure ( r (2) = 0.70, P < 0.05) and by the furosine procedure ( r (2) = 0.66, P < 0.05). In expt 2, the concentrations of total Lys and reactive Lys were reduced ( P < 0.05) when addition of CDS or drying temperature of the samples was increased, but the reduction was greater ( P < 0.05) when both CDS addition and drying temperature were increased at the same time. After oven-drying at 100 degrees C, 75.7% of total Lys was reactive in DDG, but only 27.6 and 10.2% were reactive in DDGS 20 and DDGS 40, respectively. In conclusion, reactive Lys is correlated with the concentration of SID Lys in DDGS, and addition of CDS exacerbates the negative effects of heating on the concentration of total Lys and reactive Lys in DDGS.

Factors affecting the variability in ileal amino acid digestibility in corn distillers dried grains with solubles fed to growing pigs1

Two experiments were conducted to compare the ileal digestibility of AA in distillers dried grains with solubles (DDGS) sourced from different regions (IL, MN, KY), to compare AA digestibility in DDGS and in distillers dried grains (DDG) and to compare AA digestibility in DDGS from ethanol production (DDGS(ethanol)) and DDGS from beverage production (DDGS(beverage)). In Exp. 1, five samples of DDGS(ethanol) were sourced from Minnesota (MN1, MN2), Illinois (IL1, IL2), and from Kentucky (KY). In Exp. 2, six samples of DDGS(ethanol), 1 sample of DDG, and 1 sample of DDGS(beverage) were used to compare values for apparent ileal digestibility and standardized ileal digestibility (SID) of AA between DDGS(ethanol) and DDGS(beverage) and between DDG and DDGS(ethanol). Results of Exp. 1 showed that the SID of Lys in DDGS from MN2 (72.8%) was greater (P < 0.01) than in DDGS from MN1 (66.8%), IL1 (66.8%), and KY (65.8%) but not different from IL2 (70.1%). Except for Leu and Glu, no differences in SID for any of the other AA were observed among the 5 sources of DDGS. In Exp. 2, the SID for Lys in DDGS(beverage) was greater (P < 0.01) than in DDGS(ethanol) (69.3 vs. 64.8%), but for CP and all other AA except His, no differences between the 2 types of DDGS were observed. The SID for most AA in DDG were greater (P < 0.05) than in DDGS(ethanol), which suggests that the AA in the solubles that are added to DDGS may be less digestible than the AA in DDG. In conclusion, results of these experiments confirm that the digestibility of Lys is more variable among sources of DDGS than the digestibility of other AA. However, the SID of AA among DDGS sources within a region can vary as much as among DDGS sources from different regions, and AA in DDGS(beverage) may be as digestible as AA in DDGS(ethanol). The digestibility of AA in DDG is greater than in DDGS, which indicates that AA in the solubles have a lower digestibility than AA in DDG.

Digestibility of energy and phosphorus in ten samples of distillers dried grains with solubles fed to growing pigs1

An experiment was conducted to measure DE and ME and the apparent total tract digestibility (ATTD) of energy, N, and P in distillers dried grains with solubles (DDGS) fed to growing pigs. Ten sources of DDGS were obtained from ethanol plants in South Dakota and Minnesota, and 11 diets were formulated. One diet was based on corn (96.8%), limestone, salt, vitamins, and microminerals. Ten additional diets were formulated by mixing the corn diet and each of the 10 sources of DDGS in a 1:1 ratio. Eleven growing pigs (initial BW of 29.3 +/- 0.42 kg) were allotted to an 11 x 11 Latin square design, with 11 periods and 11 pigs. Each of the 11 diets was fed to each pig during 1 period. Pigs were placed in metabolism cages that allowed for the total, but separate, collection of feces and urine. Samples were analyzed for GE, N, and P and energy and N balances, and the ATTD of GE, N, and P were calculated for each diet. By subtracting the contribution from the corn diet to the DDGS-containing diets, the energy and N balances and the ATTD for GE, N, and P for each source of DDGS were calculated. Results of the experiment showed that the DE and ME differed (P < 0.001) among the 10 sources of DDGS (3,947 to 4,593 kcal of DE/kg of DM and 3,674 to 4,336 kcal of ME/kg of DM). The average DE and ME in DDGS were 4,140 and 3,897 kcal/kg of DM, respectively. These values were not different from the DE and ME in corn (4,088 and 3,989 kcal/kg of DM, respectively). Based on the analyzed GE and nutrient composition of DDGS and the calculated values for DE and ME, prediction equations for DE and ME were developed. These equations showed that DE and ME in DDGS may be predicted from the concentration of ash, ether extract, ADF, and GE. The retention of N from DDGS was greater (P < 0.001) than from corn, but when calculated on a percentage basis, the N retention did not differ between DDGS and corn. The ATTD of P in DDGS was 59.1% on average for the 10 samples. This value was greater (P < 0.001) than the ATTD of P in corn (19.3%). It is concluded that the DE and ME in DDGS is not different from the DE and ME in corn. However, if DDGS is included in diets fed to growing swine, a greater portion of the organic P will be digested and absorbed, thus reducing the need for adding inorganic P to the diets.

Amino acid availability and true metabolizable energy content of corn distillers dried grains with solubles in adult cecectomized roosters

Five sources of corn distillers dried grains with solubles (DDGS), which varied in darkness of color, were collected from several processing plants in the Midwestern United States. Sources of DDGS were analyzed for their amino acid and energy contents, measured for color score, and evaluated for TMEn, apparent amino acid digestibility, and true amino acid digestibility. A precision-fed rooster assay was used, in which each DDGS sample was tube fed (25 g) to adult cecectomized roosters, and the excreta were collected for 48 h. The experiment was conducted as a randomized complete block design with 8 replicates. Seven adult roosters (averaging 75 wk of age) were used in each period, with 5 fed the DDGS sources and 2 fasted to estimate basal endogenous amino acid losses. One source (no. 5) was the darkest, 2 sources (no. 2 and 4) were light, whereas 2 other sources (no. 1 and 3) were intermediate in color as measured by a colorimeter. Total lysine content of the DDGS sources ranged from 0.48 to 0.76%, with the lowest lysine content in the darkest DDGS source. Apparent and true lysine digestibility was approximately 30 and 15 percentage units lower (P < 0.05), respectively, in the dark-colored source (no. 5) than in the other 4 sources. Average apparent and true digestibility of the essential amino acids were 10 and 8 percentage units lower (P < 0.05), respectively, in source 5 than the other 4 sources. The TMEn content of the 5 DDGS sources was also lower (P < 0.05) in the darkest DDGS (no. 5). Our results suggest that when the color score of a DDGS source, as measured by a colorimeter, reached a certain threshold (lightness between 28 and 34), amino acid availability and true metabolizable energy content may be reduced. This reduction was particularly evident for lysine, which had the lowest digestibility in the darkest DDGS source. These results suggest that dark-colored DDGS may have been overheated during drying, causing Maillard reactions to be more extensive and resulting in a lowered total lysine content, lysine digestibility, and TMEn content.

Determination of the ileal amino acid and energy digestibilities of corn distillers dried grains with solubles using grower-finisher pigs1,2,3

An experiment evaluated the ileal apparent and standardized AA and apparent energy digestibilities in grower-finisher pigs of 5 sources of distillers dried grains with solubles (DDGS) from corn. The 5 DDGS sources were analyzed for AA, GE, NDF, ADF, and color score. Diets were formulated to contain 15% CP from the test DDGS sources (approximately 60% of the diet). A low-protein (5% casein) diet was used to estimate basal endogenous AA losses. The experiment was conducted in 2 replicates of a 6 x 6 Latin Square design, with 6 treatments and six 1-wk periods. The experiment used 12 crossbred barrows [(Yorkshire x Landrace) x Duroc], averaging 28 kg of BW and 60 d of age, and surgically fitted with a T-cannula in the distal ileum. After a 10-d recovery period, treatment diets were fed in meal form, initially at 0.09 kg . BW(0.75). Feed intake was equalized between pigs within each period and increased for each subsequent period. Periods included 5 d of diet acclimation followed by two 12-h ileal digesta collections, one on d 6 and one on d 7. Apparent and standardized digestibility of AA was calculated using chromic oxide (0.4%) as an indigestible marker. The results demonstrated that apparent and standardized lysine digestibilities ranged from 24.6 to 52.3% and 38.2 to 61.5%, respectively. Average apparent essential AA digestibility was lower (P < 0.05) in sources 1 and 5, the 2 sources that were darkest in color. Apparent and standardized digestibility of the averaged nonessential AA were lower (P < 0.05) in source 5 than in all other sources. Source 5, the darkest colored DDGS, had a 10% lower (P < 0.05) average apparent and standardized essential AA digestibility and was more than 15% lower (P < 0.05) in lysine digestibility than the 3 lightest colored sources. Apparent ileal energy digestibility did not differ among the 5 sources. Lysine content and digestibility seemed to be reduced to a greater extent by the darker colored DDGS than the other essential AA, suggesting that the Maillard reaction reduced total lysine content and lowered its digestibility. These results, therefore, imply that darker colored DDGS sources may have lower (P < 0.05) analyzed lysine contents, as well as lower (P < 0.05) lysine and essential AA digestibilities, than lighter colored DDGS sources.

Physical, chemical, and nutritional characteristics of distillers dried grains with solubles for chicks and pigs

The physical characteristics, chemical composition, and nutritional value of distillers dried grains with solubles (DDGS) from seven beverage alcohol and two fuel alcohol manufacturers were evaluated in studies with chicks and pigs. Color scores of the DDGS ranged from very light to very dark and odor scores ranged from normal to burnt or smoky. The DDGS ranged from 23.4 to 28.7% CP, 2.9 to 12.8% fat, 8.8 to 36.9% ADIN, 28.8 to 40.3% NDF, 10.3 to 18.1% ADF, and 3.4 to 7.3% ash. Lysine concentrations of the DDGS ranged from .43 to .89%. In the first experiment, 12 corn-based diets were fed to 1-d-old chicks for 21 d to assess the nutritional value of the DDGS sources. A low-protein basal diet was supplemented with soybean meal to provide 13.6, 16.5, or 19.0% CP or supplemented with 20% DDGS, which supplied approximately the same amount of CP as the highest level of soybean meal. Weight gain, feed intake, and feed/gain were influenced (P < .01) by source of DDGS. The weight gain of chicks fed the DDGS sources ranged from 85% of that chicks fed the highest level of soybean meal to less than that of chicks fed the low-protein basal diet. Blends of the three best sources of DDGS and the three poorest sources of DDGS were evaluated in a subsequent chick trial. The relative nutritional values of the two blends were similar to the average of the sources that made up the blends. Performance responses to various blends of DDGS in the pig experiment paralleled those of the chick trial.(ABSTRACT TRUNCATED AT 250 WORDS)