Chemical composition and, therefore, potential nutritive value of corn distiller's dried grains with solubles (DDGS) is constantly evolving as the ethanol industry innovates processing techniques. We determined standardized ileal digestibility (SID) of AA (Exp. 1) and DE (Exp. 2) contents in high-protein (HP; >40% on a DM basis) DDGS samples. Two HP DDGS (HP-A and HP-B) samples and 1 conventional DDGS (CON) sample were selected for this study. Three semipurified corn starch-based diets (minimum 18% CP, as-fed basis) were formulated with DDGS as the sole source of AA. A fourth, N-free diet was prepared to estimate basal ileal endogenous AA losses. The corn starch:sucrose:oil ratio was kept constant across diets to allow calculation of DE content in DDGS by the difference method. In Exp. 1, 8 ileal-cannulated barrows (23.9 kg initial BW) were used in a replicated 4 × 4 Latin square design ( = 8). Pigs were fed at 2.8 × maintenance energy requirement. In each period, pigs were adjusted to diets for 5 d followed by a 2 d of 8 h each grab continuous ileal digesta collection. In Exp. 2, 9 barrows (24.9 kg BW) were assigned to the 4 diets in a repeated 9 × 4 Youden square design to give 9 replicates per diet. In each period, pigs were adjusted to diets for 7 d followed by 5 d of fecal grab sample collection. The analyzed CP was 30.1, 42.3, and 43.1% (on a DM basis) in the CON, HP-A, and HP-B samples, respectively; the corresponding values for GE were 5,067, 5,425, and 5,407 kcal/kg DM, respectively. The concentrations of fat and NDF were comparable among the DDGS samples. Except for Arg and Val, the SID values for indispensable AA were not different ( > 0.05) among the 3 DDGS samples. However, HP samples had higher ( < 0.05) SID values for indispensable AA and CP compared with the CON sample. The SID of Lys content was 4.9, 6.1, and 7.4 g/kg DM for the CON, HP-A, and HP-B, respectively; the corresponding values for Met and Thr were 4.6, 6.8, and 7.4 g/kg DM, respectively, and 6.8, 9.5, and 10.7 g/kg DM, respectively. The DE content in HP samples was greater ( < 0.01) than in the CON (3,614, 4,494, and 4,555 kcal/kg DM for the CON, HP-A, and HP-B, respectively). In conclusion, HP DDGS had higher SID content of AA and DE compared with the CON.

Fermenting high fiber ingredients such as distillers dried grains with solubles (DDGS) with feed enzymes may improve their feeding value. We investigated the effects of fermenting corn DDGS with a blend of β-glucanase and xylanases (XB) on growth performance, gut parameters, and apparent total tract digestibility (ATTD) of nutrients and energy in growing pigs. Dietary treatments were: (1) corn soybean meal-based diet + 30% DDGS (control), (2) control + XB without fermentation (XBNS), and (3) control + DDGS fermented with XB (16% DM) for 3 to 10 d at 40 °C (XBS). Target activities in XB were 1,050 and 5,500 U/g of DDGS for XB, respectively. Diets contained phytase at 750 FTU/kg. Feed samples were taken during fermentation and at feeding for analysis of pH and organic acids. A total of 144 pigs (25 ± 1.0 kg BW) were assigned to pens (three barrows and three gilts) and allocated to the three diets in a two-phase feeding program (3 wk/phase). Diets were fed on ad libitum and were delivered by a computer-controlled liquid feeding system at a feed to water ratio of 1:4, four times per day. Pigs had free access to water. Fecal samples were taken in the final 3 d of phase 2 to determine ATTD using TiO2 marker method and one pig per pen was euthanized for gastrointestinal (GIT) measurements. The pH of diets at feeding time was lower (P < 0.01) for XBS (4.72) compared with control (5.45) and XBNS (5.45). Pigs fed XBNS had higher (P = 0.04) ADG than control in phase 1. In phase 2 and the overall (weeks 0 to 6), ADG and final BW were higher (P = 0.01) for XBNS than XBS but were not different (P > 0.05) from control. There were no diet effects (P > 0.05) on ADFI. Feed to gain (FCR) for XBNS (1.68) and XBS pigs (1.69) was better (P < 0.01) than for control pigs (1.78) in phase 1. There were no diet effects (P > 0.05) on FCR in phase 2 or in the overall. Pigs fed XBNS had lower (P < 0.01) ATTD of CP than control and XBS-fed pigs. Although not different (P > 0.05) from control, pigs fed XBNS had lower (P < 0.05) jejunal crypt depth and ATTD of gross energy than pigs fed XBS. In conclusion, treating corn DDGS with XB with or without liquid fermentation improved feed efficiency in phase 1, suggesting degradation of dietary fibrous components that may limit nutrient utilization in younger pigs. However, these benefits were not observed in phase 2.

Treating fibrous feed ingredients with exogenous feed enzymes may improve their utilization in monogastric animals. An in vitro study was conducted to determine the effects of steeping corn distillers dried grains with solubles (DDGS) or wheat middlings (WM) with exogenous feed enzymes. Four treatments were arranged as follows: 1) co-product steeped with water (CON), 2) CON plus 0.5 g fiber degrading enzymes (FDE), 3) CON plus 0.5 g protease (PRO), and 4) CON plus 0.5 g FDE and 0.5 g PRO (FDEPRO). The FDE contained about 62,000, 37,000, and 8,000 U/g of xylanase, cellulase, and β-glucanase, respectively whereas activities in PRO amounted to 2,500,000, 1,300,000 and 800,000 U/g of acid, alkaline and neutral proteases, respectively. Briefly, 50 g of DDGS or WM samples (n=8) were mixed with 500 mL water with or without enzymes and steeped for 0 to 72 h at 37℃ with continuous agitation. The pH, concentration of monosaccharides, and organic acids in the supernatant and apparent disappearance (AD) of fiber in solids were measured at 0, 12, 24, 48, and 72 h. There was treatment and time interaction (P&lt;0.005) on monosaccharides concentration. At 12 h, arabinose and glucose concentrations were similar (P&gt;0.05) between FDE and FDEPRO but higher (P=0.002) than for CON in DDGS. For WM, FDE and FDEPRO had higher (P&lt;0.001) xylose concentration than CON and PRO whereas glucose concentration was higher (P&lt;0.001) for enzymes than CON at 12 h. However, FDEPRO had higher (P&lt;0.001) xylose concentration than CON whereas xylose concentration for FDE and PRO was intermediate at 24 h. There was an interaction (P&lt;0.05) between treatment and time effect on lactic acid concentration in DDGS and WM (P&lt;0.005), and acetic acid concentration in WM (P&lt;0.001). In general, monosaccharides concentration was higher between 12 and 24 h and decreased after 48 h, whereas the pH decreased, and concentration of organic acids increased continuously over time (P&lt;0.05). The AD of NDF and ADF in DDGS was greater (P=0.001) for FDE and FDEPRO than CON and PRO at 72 h. In WM, enzymes increased (P=0.007) AD of NDF relative to CON at 72 h. Nonetheless, greater (P&lt;0.05) AD of fiber was observed between 48 and 72-h. In conclusion, although there were differences in responses among co-products, fiber degrading enzymes increased release of fermentable monosaccharides from co-products at 12 to 24 h of steeping and these effects were not extended with the addition of protease.

No abstract

The use of corn distillers dried grains with solubles (DDGS) in pig diets is limited due to high fiber concentration. Steeping with exogenous fiber-degrading enzymes (FDE) may improve their feeding value. We evaluated apparent ileal digestibility (AID), standardized ileal digestibility (SID), and apparent total tract digestibility (ATTD) of components and DE content in DDGS steeped without or with two commercial FDE (A and B). Mixture of 350 g of DDGS, FDE (none for control), and 1.5 liters of water was incubated at 40 °C for 24 h with 15 min agitation every 40 min. FDE-A (pure combination) supplied 5,500 U of xylanase and 1,050 U of β-glucanase while FDE-B (multienzyme complex) supplied 1,200 U of xylanase, 150 U of β-glucanase, 500 U of cellulase, and 5,000 U of protease per kg of DDGS plus side activities. Samples were taken at time 0, 4, 8, and 24 h for organic acids and pH measurements. Three semi-purified corn starch-based diets were formulated with steeped DDGS as the sole source of CP. The basal mixture contained 0.2% TiO2 as indigestible marker. Six ileal-cannulated pigs (20 kg BW) were fed the three diets in a replicated 3 × 3 Latin square design to give six replicates per diet. Pigs were fed at 2.8× maintenance energy requirements and had free access to water. In each period, pigs were adjusted to diets for 7 d followed by 2 d for grab fecal and 2 d of 8 h continuous ileal digesta collection. There were no (P > 0.05) treatment and sampling time interaction or treatment effects on pH and lactic concentration. Lactic and acetic acids increased, and pH decreased (P < 0.05) over time points. The AID of CP, NDF, and crude fat and SID of CP were not different (P > 0.05) among treatments. Steeping DDGS with FDE-A had lower (P = 0.01) ATTD of NDF than control but higher (P = 0.001) ATTD of crude fat compared with the control or DDGS steeped with FDE-B. Values for DE content in steeped DDGS were not different (P > 0.05) and amounted to 4,095, 4,039, and 3,974 kcal/kg DM for the control, FDE-A, and FDE-B, respectively. In conclusion, under conditions of the study, steeping DDGS with exogenous enzymes did not improve fiber and energy digestibility.