Total Tract Starch Digestibility Research Articles

PSVIII-3 The functional properties and digestibility of round and wrinkled pea flour in swine diets

Abstract Wrinkled and round pea flour display physical and compositional differences. Wrinkled peas have reduced activity of the starch branching enzyme, which decreases amylopectin production. As a result, wrinkled peas have an increased proportion of amylose, relative to round peas. The rate and extent of starch digestion are influenced by the ratio of amylose to amylopectin in starch. Extrusion results in swelling of the starch, altering the crystalline structure. The objective of this study was to determine the role of the amylose to amylopectin ratio and extrusion on starch digestibility and microbial characteristics in growing pigs. Ileal-cannulated barrows (n = 8) with an initial body weight (BW) of 40 ± 1 kg were randomly assigned to 1 of 4 dietary treatments (n = 8 pigs/treatment) in a replicated Latin square design with four blocks. Dietary treatments were round pea flour (RPF), extruded round pea flour (RPF-E), wrinkled pea flour (WPF), and extruded wrinkled pea flour (WPF-E). The starch content decreased in the native WPF (36.7%) and WPF-E (34.7%) compared with RPF (50.1%) and RPF-E (49.1%). However, the amylose content in native WPF (77.1%) and WPF-E (70.7%) was greater compared with RPF (40.1%) and RPF-E (39.8%). Ileal digestibility of starch differed between pea flours (P < 0.05), greatest for RPF (92.8%) and RPF-E (92.2%) and least for WPF (80.2%) and WPF-E (76.7%). Total tract digestibility was least for RPF (98.7%) compared with other treatments (P < 0.05). Total tract digestibility of starch was greatest with RPF-E compared with RPF (99.5% vs 98.7%, P < 0.01) but was not different from WPF (99.25%) or WPF-E (99.51%). Shannon index, an indicator of microbial diversity, decreased in ileal digesta of WPF-E-fed pigs compared with RPF-E (P < 0.05) but similar among treatments in the feces. In summary, compared with WPF or WPF-E, RPF and RPF-E had reduced amylose content and greater starch digestibility determined at the end of the ileum; however, total tract digestibility of starch was similar among all treatments. Furthermore, RPF-E compared with RPF, WPF, and WPF-E increased microbial diversity in the ileal digesta, but no difference among treatments in the feces.

PSLBI-9 The growth performance and total tract starch digestibility of finishing Nelore bulls fed flint corn-based diets are improved by the corn processing method and urea source

Abstract The aim of this study was to evaluate the flint corn processing method (CPM) and urea source for finishing Nellore bulls fed corn-based diets. In this study, 80 Nellore bulls [initial body weight (BW) = 388 ± 45.7 kg] were allocated into 28 pens (7 pens/treatment; 6 pens with 3 bulls + 1 pen with 2 bulls). A completely randomized design with a 2 × 2 factorial arrangement of treatments was used to test two CPMs: dry ground corn (DGC) and reconstituted and ensiled corn (REC), and two US: feed-grade urea (FGU) and post-ruminal release urea (PRU). Dietary inclusion (% DM) of flint corn (vitreousness = 86.0%) was 61.3% (DGC or REC), and urea source addition was 0.5% as non-protein nitrogen (NPN; as FGU or PRU). The PRU source (Trouw Nutrition, Netherlands) contained 82% urea on a DM basis. In an in vitro assay, 27% of this urea was released into the rumen. Experimental period lasted 100 d (with 14 d of adaptation). Fecal samples from each bull were collected in two periods of three consecutive days (d 44 to 46 and 94 to 96) at different time (0600, 1200, and 1800 h). Samples were composited by pen and analyzed for fecal starch (FS) and indigestible NDF as markers for fecal excretion. At the end of the experiment, bulls were slaughtered and the jejunum and pancreas were sampled from one bull per pen. Interaction effects were not found (P ≥ 0.31) for any feedlot growth performance variables (Table 1). Final BW, average daily gain, and feed efficiency (gain to feed; G:F) were greater for bulls fed REC and PRU than for those fed DGC and FGU (P < 0.02), respectively. As a result, observed dietary net energy (NE) for maintenance and BW gain were about 7.0% and 9.0% greater for bulls fed REC diets, and 4.3% and 5.6% greater for bulls fed PRU diets, respectively. Bulls fed DGC had 2.2 times greater FS compared with bulls fed REC, resulting in lower fecal pH and total tract starch digestibility (TSD) for bulls fed DGC compared with those fed REC (P < 0.01). Interestingly, a similar trend was observed in bulls fed PRU compared with those fed diets with FGU (P < 0.06). Jejunal gene expression of SLC5A1 was not affected by treatments (P > 0.14). Nevertheless, bulls fed diets with PRU presented greater jejunal α-amylase activity (P = 0.02). Pancreatic α-amylase activity was less when bulls were fed DGC + PRU diet. In conclusion, REC markedly improved TSD and growth performance compared with DGC. Additionally, independent of CPM, PRU inclusion as NPN source increased G:F and dietary NE concentration due to the positive effects on jejunal amylase activity and TSD.

250 Effects of corn processing on growth performance, starch digestibility, and blood metabolites in receiving beef steers

Abstract Corn is the most common grain ingredient fed to feedlot cattle in the U.S. and most corn goes through some processing to increase the energy availability. This study examined the effects of a novel corn processing method on the growth performance, starch digestibility, and blood metabolites of growing steers compared with traditional corn processing methods. Angus-cross steers [n = 218; body weight (BW) = 230 ± 18.5 kg] were sorted into pens of 6 or 7 steers upon arrival and fed a common receiving diet for 2 d prior to being weighed, processed, and starting dietary treatments (n = 12 pens/treatment) on d 0. Treatments included diets with dry rolled corn (ROLL), steam flaked corn (FLAKE), and high shear dry extruded corn (EXT; High-Gel Insta-Pro International, Grimes, IA). Corn was included at 30% DM of a corn silage and SweetBran-based diet. Due to illness concerns, diets were adjusted to reduce corn in the diet to 25% on d 5; in feed antibiotic was fed d 5 to 9, and all calves were weighed and administered Draxxin (1.1 mL/45.45 kg) on d 17. Final BW were collected on d 37 and 38 and serum (glucose, insulin) and fecal samples (total tract starch digestibility) were collected from one steer per pen. Data were analyzed using the Mixed procedure of SAS 9.4 (Cary, NC) with pen as the experimental unit. Treatment did not affect midpoint (d 17) BW or average daily gain (ADG) from d 0 to 17 (P ≥ 0.31). Final BW, ADG, and dry matter intake were not different between treatments (P ≥ 0.15). Feed efficiency (gain:feed) was greatest in EXT (0.261) compared with ROLL (0.232) with FLAKE (0.259) being intermediate and not different from other treatments (P = 0.007). Total tract starch digestibility was determined using the equations from Zinn et al. (2007) and was increased in EXT and FLAKE compared with ROLL (P = 0.0002). Serum glucose and insulin on d 36 were not affected by treatment (P ≥ 0.19). Overall, a growing diet of 25% high shear dry extruded corn increased feed efficiency and total tract starch digestibility over dry rolled corn and resulted in similar performance to steers fed steam flaked corn.

Effect of supplementing an α-amylase enzyme or a blend of essential oil components on the performance, nutrient digestibility, and nitrogen balance of dairy cows

Lowering dietary protein content is a promising strategy to reduce N excretions in cattle but it requires improved N utilization by the animal. Feed enzymes (e.g., exogenous α-amylase) and plant extracts (e.g., essential oils [EO]) are 2 additives that may enhance rumen function and possibly also microbial protein yield. This may increase fat- and protein-corrected milk yield (MY) and milk nitrogen efficiency and thus lower N losses from dairy cows. Both types of additives were studied in an experiment including 39 Holstein cows that had (average ± SD) 40.7 ± 7.95 kg/d MY, 89 ± 43 DIM, 2.7 ± 1.5 lactations, and 677 ± 68.6 kg of BW, consisting of a covariate (4 wk) and treatment period (5 wk). During the whole experiment cows were fed a typical Benelux diet (CTRL), supplemented with concentrates to meet individual requirements for energy and MP, which were fulfilled for 100% and 101%, respectively. The total diet was low in CP (15.5%) and relatively high in starch (22.6% and 6.6% rumen bypass starch). Cows were balanced for parity, DIM, MY, and roughage intake and randomly assigned to one of 3 groups, which received the following treatments in the treatment period: (1) CTRL (n = 13); (2) CTRL + 14 g/cow per day Ronozyme RumiStar α-amylase enzyme (AMEZ, n = 13; DSM); and (3) CTRL + 2.5 g/cow per day Crina Protect, a blend of EO components (ESOL, n = 13; DSM). Animal performance, ruminal pH, and enteric gas emissions were monitored throughout the experiment. During the last week of the covariate and treatment periods, nitrogen balances were conducted, total-tract nutrient digestibility was determined, and urinary allantoin and uric acid were determined as indicators for microbial N production. The statistical model applied to these variables contained group and DIM during treatment period as fixed effects and the values from the covariate period as covariate. Post hoc Dunnet-corrected comparisons between each treatment group and the control group were explored. The α-amylase enzyme tended to increase apparent total-tract starch digestibility and increased milk lactose concentration. The EO blend tended to increase MY and increased milk N output, milk nitrogen efficiency, and feed efficiency. Therefore, when feeding reduced dietary protein levels, EO have potential to improve the N-use efficiency in cattle, whereas the α-amylase enzyme might increase starch digestibility and milk lactose. However, additional research is necessary to substantiate our findings.

Effects of Lentilactobacillus buchneri and chemical additives on fermentation profile, chemical composition, and nutrient digestibility of high-moisture corn silage.

High-moisture corn silage presents a novel approach to reduce forage feeding expenses and enhance animal performance. Nevertheless, given corn's proclivity for starch, suboptimal fermentation quality in high-moisture corn silage can lead to spoilage, posing risks to livestock well-being. Therefore, the objective of this study is to evaluate the effects of different additives on the fermentation profile, chemical composition, nutrient digestibility of high-moisture corn (HMC) silage. All treatments improved the quality of high-moisture corn silage fermentation, as demonstrated by a decrease in pH and increase in lactic acid (LA) content. The high-moisture corn silage had a low content of trans fatty acids (TFA). Fermentation effectively decreased prolamin content while increasing 48-h in vitro dry matter digestibility (IVDMD), estimated total tract starch digestibility (eTTSD), total digestible nutrient (TDN), and relative grain quality (RGQ) of high-moisture corn silage. Nonetheless, no effect was observed on the 48-h IVDMD of high-moisture corn silage among the different treatments. Pearson's correlation analysis indicated that neutral detergent fiber (aNDF), neutral detergent insoluble protein (NDIP), crude protein (CP), zein, and prolamin closely correlated with the digestibility of high-moisture corn. The study's findings demonstrate that inoculating L. buchneri and potassium sorbate can improve the quality of high-moisture corn silage fermentation and digestibility in different hybrids. The results will provide insights for enhancing farm productivity and profitability in China.

PSXIII-17 Feeding Sorghum Silage: Effects of Grain Processing on Intake and Apparent Total Tract Digestibility of Backgrounding Beef Heifers

Abstract This study evaluated the effect of processing sorghum silage (SS) at harvest on dry matter intake and nutrient digestibility of beef cattle. A dual-purpose sorghum (ADV2450IG, Advanta seeds, Irving, TX) was harvested (Claas Jaguar 930, Harsewinkel, Germany) at the late-dough stage of grain maturity and processed (PRO) or not (NPR) with a specific SS cracker (196 mm rolls of 125 teeth each, 40% speed differential, 1.1 mm roll gap). Whole-plant was chopped at 15 mm and ensiled in polyethylene ag-bags (60 m long and 2.74 m diameter) for 60 d until the beginning of a performance trial which was followed by the digestibility trial. From a performance trial with eight heifers/pen and 12 pens total (six per treatment), one heifer (13 ± 1.5 mo and 251,4 ± 36.3 kg of BW) by pen was randomly selected for the digestibility trial. Two backgrounding diets containing (DM basis), 90.5% SS either PRO or NPR, 6.5% soybean meal (expeller) and 3% supplement (ROC90, Provimi, Argentina); continued to be offered ad libitum for an extra 3 d of adaptation, while feed and feces were collected the next 4 d. Feed was individually offered once daily, and orts were collected the following day. Fecal samples were collected twice daily and apparent total tract digestibility was determined using uNDF240h as a marker. Data were analyzed as a completely randomized design using pen as the experimental unit, and initial BW as a covariate. Dry matter (DM) and organic matter (OM) intake tended (P > 0.07) to be greater, while starch intake was greater (P < 0.03) for the NPR treatment. intake of NDF, ADF and CP were not affected by treatments. No differences (P > 0.10) were detected for DM, OM, NDF, ADF and CP digestibility, while starch digestibility was greater (P < 0.001) by processing (93.55 vs. 86.48 for PRO and NPR, respectively). In conclusion, processing sorghum silage at harvest increased apparent total tract digestibility of starch when SS was fed to backgrounding beef heifers.

Parity and nutrient total-tract digestibility in dairy cows during transition period

Cows experience many physiological, nutritional and social changes during transition period. This study aims to evaluate the differences in nutrients total-tract digestibility (nTTD) between primiparous (PP) and multiparous (MP) cows through the transition period. From -23, -5, 0, 7, 14, and 30 days from calving a sample of feed and feces samples were collected from 25 Holstein cows (11 PP and 14 MP) as well as daily rumination time through accelerometers.The results show that average nTTD were different (p ≤ 0.02) for amylase-treated neutral detergent fiber organic matter (aNDFom) and potentially digestible neutral detergent fiber (pdNDF240; 52.5 vs. 54.0 and 78.8 vs. 81.3, respectively in PP vs. MP), while no differences were found regarding pdNDF24 and starch (88.5 vs. 88.6 and 95.1 vs. 96.1, respectively in PP vs. MP). Total-tract starch digestibility (TTstarchD) was different among timepoints (p < 0.01), going from an average of 91.40 up to 97.39% of starch, on times -23 and 14, respectively. Differences in total-tract digestibility of aNDFom among timepoints (p < 0.01) was expected because of differences in diet composition among lactating and non-lactating cows. No differences in daily rumination time (p = 0.92), TTstarchD and total-tract potentially digestible NDF digestibility at 24 h (TTpdNDF24D) were recorded. Our findings show that fiber digestibility during the transition period is higher in MP probably for a different ruminal retention time. These differences should be considered when formulating rations for groups with different parity number.

Effect of short-term abomasal corn starch infusions on postruminal fermentation and blood measures

It is possible that some of the systemic responses to subacute ruminal acidosis (SARA) may be caused by increased intestinal starch fermentation. The objective of this experiment was to evaluate the effect of abomasal infusion of up to 3 g of corn starch/kg body weight (approximately 1.6 kg of starch/d) on fecal measures of fermentation, plasma acute phase proteins, and white blood cell populations. Six ruminally cannulated cows in late lactation were randomly assigned to duplicate 3 × 3 Latin squares with 21-d periods. Cows were fed a 20.6% starch TMR twice daily and during the last 7 d of each period cows were abomasally infused with corn starch at 0 (CON), 1 (ST1), or 3 (ST3) g/kg body weight split into 2 bolus infusions, provided every 12 h. Fecal samples were collected at 0, 6, 12, and 18 h following feeding on d 21 and were analyzed for pH, VFA, lactic acid, and lipopolysaccharide (LPS). Composite fecal samples were used to estimate apparent total-tract nutrient digestibility using undigested neutral detergent fiber as an internal marker. Blood samples were collected at 0 and 6 h relative to feeding on d 14, 18, and 21 of each period. Concentrations of haptoglobin and serum amyloid A in plasma were measured in all samples, 0 h samples on d 14 and 21 were used to measure white blood cell populations, and 0 h samples from d 14, 18, and 21 were used for flow cytometric analysis of γδ T cells. Data were analyzed in SAS using models that included fixed effects of treatment and period and the random effects of cow and square. For blood measures, d 14 samples collected before the initiation of abomasal infusions were included as covariates. Time (d or h) was added as a repeated measure in variables that included multiple samples during the abomasal infusion period. A contrast was used to determine the linear effect of increasing abomasal corn starch. Abomasal corn starch linearly decreased fecal pH and linearly increased fecal total VFA and LPS, but effects were modest, with fecal pH, total VFA, and LPS changing from 6.96, 57.7 mM, and 4.14 log10 endotoxin units (EU) per gram for the CON treatment to 6.69, 64.1 mM, and 4.58 log10 EU/g for the ST3 treatment, respectively. This suggests that we did not induce hindgut acidosis. There were no effects of treatment on apparent total-tract starch digestibility or fecal starch content (mean of 96.9% and 2.2%, respectively). Treatment did not affect serum acute phase proteins or most circulating white blood cells, but the proportion of circulating γδ T cells tended to linearly decrease from 6.69% for CON to 4.61% for ST3. Contrary to our hypothesis, increased hindgut starch fermentation did not induce an inflammatory response in this study.

Feed intake, digestibility, ruminal fermentation, growth performance, and carcass traits of lambs fed corn silage treated with Lentilactobacillus buchneri and stored for different times

Our objective was to investigate the impact of inoculation and storage length of flint corn silage on the metabolic and production responses of lambs. A flint corn hybrid was harvested with 315 g dry matter (DM)/kg and ensiled in concrete pipe silos without (control) or with Lentilactobacillus buchneri CNCM I-4323 at 1 × 105 cfu/g of fresh forage for 120, 240 and 360 d (n = 2 for each treatment). Such silages were used to formulate six different diets. Sixty non-castrated male Dorper × Santa Inês lambs were used in the feeding program (n = 10). Additionally, eight ruminally cannulated Dorper × Santa Inês crossbred lambs were used to measure the ruminal fermentation (n = 4). Extending the storage of corn silage from 120 to 360 d increased the contents of soluble protein (P = 0.030; 415–490 g/kg CP) and ammonia-N (P = 0.047; 82.5–114 g/kg total N). Compared to the control, inoculation resulted in higher (P < 0.05) concentration of lactic (+19.9 %) and acetic acid (+38.6 %), and lower butyric acid (–25.3 %), ammonia-N (–23.5 %), and DM loss (–36.2 %). The aerobic stability of corn silage was also improved by inoculation (P = 0.002; +160 h compared to the control). An interaction between storage length and inoculation was reported for feed intake, and lambs had increased DMI (P < 0.001) by feeding the inoculated silage stored for 120 d. Overall, the total-tract starch digestibility increased (P = 0.041) with longer storage (120 d = 94.4 %; 240 d = 95.7 %; 360 d = 96.5 %). However, the total VFA was unchanged (P > 0.05) while the ruminal molar proportion of propionate decreased from 22.8 to 20.7 mM/100 mM in lambs fed corn silage stored for 120 and 360 d (P = 0.004). Lengthening silage storage from 120 to 240 and 360 d tended (P = 0.06) to increase the ADG of lambs by 4.6 % and 10.2 %, respectively (120 d = 0.216 kg/d; 240 d = 0.226 kg/d; 360 d = 0.238 kg/d). Moreover, the feed efficiency was substantially improved (P = 0.008) by 5 % and 14 % when the silages were stored for 240 and 360 d compared to 120 d. In opposite, inoculation had no effect (P > 0.05) on ADG and feed efficiency of lambs. Final hot carcass weight (data ranged from 16.8 to 17.2 kg) and 12th rib longissimus muscle area (data ranged from 13.8 to 14.7 cm2) were not affected by treatments (P > 0.05). Overall, only few parameters of carcass and meat traits of lambs were altered by storage length and inoculation, but it were of minor biological importance. In conclusion, the productivity responses of lambs were enhanced by increasing the storage length of flint corn silage, but inoculation with L. buchneri did not contribute to improve animal performance.

Effect of Particle Size of Silage of Flint Corn Grain on Dairy Cows Fed Tropical Pasture: Performance, Intake, Ruminal Fermentation, and Digestibility.

The particle size (PS) of reconstituted corn (REC) can affect the grinding rate and starch digestibility in dairy cows. We evaluated the effect of the PS of REC ensiled for 40 days on the pasture dry matter intake (DMI), lactation performance, total tract digestibility, and ruminal fermentation of grazing dairy cows. The treatments were coarse REC (CO, 1694 µm), fine REC (FI, 1364 µm), or finely ground (GC, 366 µm) flint corn (68% vitreousness) at 29.6 ± 1.4% of diet DM (mean ± SD). Eighteen dairy cows (mean milk yield 21.3 kg/d) were split into three groups by production level and were assigned within each group to a sequence of treatments in 3 × 3 Latin squares of 21-day periods. Cows were individually fed a constant amount of whole-plant corn silage 3 ×/d (2.7 kg DM/d) and corn treatments and soybean meal according to their group. There was no significant interaction between treatment and the production level. Cows fed FI had a lower DMI (16.7 vs. 18.1 kg/d) than those fed GC, and both did not differ from CO (17.7 kg/d). There was no treatment effect on milk yield (mean: 19.2 kg/d). Cows fed CO had the lowest total tract digestibility of starch (86.3 vs. 92.3% of intake) and the highest fecal starch concentration (7.0 vs. 4.0% of DM). The NDF digestibility was lower for GC-fed cows than CO- and FI-fed cows. Plasma glucose was higher in cows fed FI and CO (75.0 mg/dL) than those fed GC (70.8 mg/dL). Ruminal volatile fatty acids and the pH did not differ. Fine grinding of REC increased the feed efficiency relative to CO and GC. Coarse grinding of REC ensiled for 40 days reduced the total tract starch digestibility relative to FI and GC.

Effects of corn silage and grain expressing α-amylase on ruminal nutrient digestibility, microbial protein synthesis, and enteric methane emissions in lactating cows

Increasing ruminal starch digestibility has the potential to improve microbial protein synthesis (MPS), milk production, and feed efficiency. Enogen corn (Syngenta Seeds LLC) expresses high α-amylase activity, and we evaluated effects of Enogen corn silage (CS) and grain (CG) on ruminal starch digestibility, MPS, and milk production in lactating dairy cows. Fifteen Holstein cows (6 ruminally cannulated and 9 noncannulated; average ± standard deviation at the beginning of the trial: 170 ± 40 d in milk; milk yield, 37.2 ± 7.73 kg/d; body weight, 714 ± 37 kg) were used in a replicated 3 × 3 Latin square design (28 d per period) with 3 treatments: a diet containing isoline CS and CG (control, CON); a diet with Enogen CS and isoline CG (ECS); and a diet with Enogen CS and CG (ECSCG). Dry matter (DM; 30%), starch (35% of DM), and particle size distribution of the isoline and Enogen CS were similar. However, the mean particle size of Enogen CG was larger (1.05 vs. 0.65 mm) than that of the isoline CG. Cannulated cows were used for digestibility and nutrient flow measurements, noncannulated cows were used for enteric CH4 measurements, and all cows were used for production evaluation. Dry matter intake (DMI) and milk yield were greater for ECS and ECSCG compared with CON (26.7 and 26.6 vs. 25.1 kg/d and 36.5 and 34.1 vs. 33.1 kg/d, respectively) without a difference between ECS and ECSCG. Milk protein yield was greater (1.27 vs. 1.14 and 1.17 kg/d) for ECS compared with CON and ECSCG. Milk fat content was greater (3.79 vs. 3.32%) for ECSCG compared with ECS. Milk fat yield and energy-corrected milk did not differ among treatments. Ruminal digestibilities of DM, organic matter, starch, and neutral detergent fiber were not different among treatments. However, ruminal digestibility of nonammonia, nonmicrobial N was greater (85 vs. 75%) for ECS compared with ECSCG. Total-tract apparent starch digestibility was lower (97.6 and 97.1 vs. 98.3%) for ECS and ECSCG compared with CON, respectively, and tended to be lower (97.1 vs. 98.3%) for ECSCG compared with ECS. Ruminal outflows of bacterial OM and nonammonia N tended to be greater for ECS than for ECSCG. Efficiency of MPS tended to be greater (34.1 vs. 30.6 g of N/kg of organic matter truly digested) for ECS versus ECSCG. Ruminal pH and total and individual short-chain fatty acid concentrations did not differ among treatments. Concentration of ruminal NH3 for ECS and ECSCG was lower (10.4 and 12.4 vs. 13.4 mmol/L, respectively) compared with CON. Methane per unit of DMI decreased for ECS and ECSCG compared with CON (11.4 and 12.2 vs. 13.5 g/kg of DMI, respectively) without a difference between ECS and ECSCG. In conclusion, ECS and ECSCG did not increase ruminal or total-tract starch digestibility. However, the positive effects of ECS and ECSCG on milk protein yield, milk yield, and CH4 per unit of DMI may show potential benefits of feeding Enogen corn. Effects of ECSCG were not apparent when compared with ECS, partly due to larger particle size of Enogen CG compared with its isoline counterpart.

Digestibility of western Canadian finishing beef cattle diets when short-season, high-moisture shelled corn and snaplage partially replace dry-rolled barley grain and barley silage

The objective of this study was to determine the effects of substituting barley grain with short-season, high-moisture shelled corn, and barley grain and barley silage with snaplage on ruminal fermentation and the site and extent of digestion in beef cattle fed finishing diets. Six ruminally and duodenally cannulated heifers (420 ± 16.4 kg body weight) were fed a barley grain and silage finishing diet (BG), a diet where half of the barley grain was replaced with high-moisture shelled corn (HC), or a diet where the barley silage and a portion of grain were replaced with snaplage (SN) in a replicated 3 × 3 Latin square design. While dry matter and starch intake were unaffected, feeding SN resulted in greater ( P = 0.02) ruminal but not total tract starch digestibility than BG. Ruminal pH did not differ between HC and BG, but SN reduced ( P = 0.02) minimum ruminal pH relative to BG. Feeding BG increased ( P = 0.04) ruminal ammonia concentrations over HC. In conclusion, high-moisture shelled corn can partially replace barley grain with minimal impact on nutrient digestibility or ruminal fermentation, but replacement of barley silage and some barley grain with snaplage may increase the risk of ruminal acidosis.

The effect of amylase supplementation on individual variation, growth performance, and starch digestibility in broiler chickens

The objective of this study was to evaluate the variance of starch digestibility in broilers individually fed diets without or with supplemental exogenous amylase. A total of 120 d-of-hatch male chicks were individually reared from 5 to 42 d in metallic cages and fed maize-based basal diets or diets containing 80 kilo-novo-α-amylase units/kg (60 birds or replicates per treatment). Beginning on d 7, feed intake, body weight gain, and feed conversion ratio were recorded; partial excreta collection was conducted every Monday, Wednesday, and Friday until 42 d, when all birds were sacrificed for individual collection of duodenal and ileal digesta. Lower feed intake (4,675 vs. 4,815 g) and feed conversion ratio (1.470 vs. 1.508) were observed in amylase-fed broilers during the overall period (7-43 d; P < 0.01), whereas body weight gain was not affected. Amylase supplementation improved total tract starch (TTS) digestibility (P < 0.05) on each day of excreta collection (except for d 28, where no difference was found), averaging 0.982 vs. 0.973 compared to basal-fed broilers from d 7 to 42. Both apparent ileal starch (AIS) digestibility and apparent metabolizable energy (AMEN) were increased (P <0.05) from 0.968 to 0.976 and from 3,119 to 3,198 kcal/kg, respectively, with enzyme supplementation. Activity of amylase in the duodenum was higher (18.6 vs. 50.1 IU/g of digesta) in supplemented birds. Amylase supplementation led to a reduced coefficient of variation for both TTS (averaged 2.41 vs. 0.92% from 7 to 42 d) and AIS digestibilities (1.96 vs. 1.03%), as well as AMEN (0.49 vs. 0.35%), when compared to the nonsupplemented group, indicating lower individual heterogenity. An age effect was detected for TTS digestibility, as both groups saw an increase during the first weeks (slightly more pronounced in the supplemented group); older birds (d 30 onwards) presented a lower TTS digestibility compared to ages between 7 and 25 d. In conclusion, amylase supplementation in maize diets for broilers can attenuate individual bird variation for starch and energy utilization by increasing amylase activity and enhancing starch digestibility.

Effects of the density of extruded pellets on starch digestion kinetics, rumen fermentation, fiber digestibilityand enteric methane production in dairy cows.

Dynamics of starch digestion in dairy cows fed extruded pellets differing in physical functional properties were investigated by measuring starch digestibility, post-prandial rumen fermentation patterns, and post-prandial duodenal starch appearance. Additionally, starch digestion effects on neutral detergent fiber (NDF) digestibility and methane (CH4 ) emission were studied. Pure barley was extruded to produce three treatments having pellets of either low-density (LD), medium-density (MD)or high-density (HD). The experiment was conducted in a 3 × 3 Latin square design using three lactating Danish Holstein cows fitted with ruminal, duodenaland ileal cannulas. After the allocation of experimental concentrate directly into the rumen through the rumen cannula, cows were fed a basal diet low in starch. Eight samples were collected on equal time intervals (9 h) from duodenal digesta, ileal digestaand feces (grab sample) to determine digestibility. For post-prandial rumen fermentation patterns, four sample sets of rumen dorsal, medialand ventral fluid were taken from each cow, whereas for post-prandial duodenal starch appearance, 14 samples of duodenal chyme were obtained from each cow relative to morning feeding of experimental concentrate at 07:00 h. Ruminal, small intestinal, hindgutand total tract digestibility of starch did not differ among treatments. Similarly, NDF digestibility and CH4 emission also remained unaffected by treatments. However, compared with the LD and MD treatments, the HD treatment showed higher acetate: propionate ratio at all positions in the rumen and a higher post-prandial duodenal starch appearance. This indicates lower ruminal starch degradation (RSD) and higher starch flow into the small intestine for HD treatment. In conclusion, the current study indicates that pellets' physical properties can manipulate RSD, where pellets with high densityand fluid stability can partly shift starch digestion from the rumen to the small intestine. Indeed, further investigations are needed.

PSVI-18 Effect of Processing Method and Severity for Hybrid Fall rye on dry Matter Intake, Ruminal Fermentation, and Apparent Total Tract Nutrient Digestibility in Ruminally Cannulated Beef Heifers

Abstract This study evaluated the effect of processing method and severity of hybrid fall rye on dry matter intake (DMI), ruminal fermentation, and apparent total tract nutrient digestibility for beef cattle. Ruminally cannulated Simmental heifers (n = 8; 327±33 kg) were used in a replicated 4×4 Latin square (21-d periods) balanced for carry-over effects with a 2×2 factorial treatment. Tempered rye [water added to achieve 80% dry matter (DM)] was compared with dry-rolled rye. Roller gap width of 1.23-mm and 0.8-mm were used for coarse and finely processed rye, respectively. This resulted in processing index values of: 80.9% for dry-rolled and coarse; 72.7% for dry-rolled and fine; 92.9% for tempered and coarse; and 88.2% for tempered and fine processed rye. Diets (DM basis) included hybrid rye grain (86%), barley silage (15%), mineral (6%), and dry distillers’ grain plus solubles (3%). Feeding tempered rye increased (P&amp;lt; 0.01) DMI by 0.87 kg compared with dry-rolled rye, and feeding coarse rye increased (P=0.04) DMI by 0.33 kg compared with fine rye. Cattle fed dry-rolled and finely processed rye had greater (P&amp;lt; 0.04) area that pH was &amp;lt; 5.5 compared with tempered and coarse rye, respectively. Ruminal short-chain fatty acid concentrations and ammonia were not affected (P≥0.12). Feeding dry-rolled rye increased DM digestibility by 2.4% (P=0.02), and crude protein digestibility in 3.0% (P=0.01) compared with tempered rye. Starch digestibility was not affected by processing severity of dry-rolled rye, but increased from 92.8 to 95.9% for tempered rye with increasing severity (interaction, P=0.03). Rolling tempered rye at the same roller gap as dry-rolled rye decreases processing severity but may allow for a greater severity of processing without marked reductions in DMI and ruminal pH, while achieving similar total tract starch digestibility. When increasing processing severity (81 vs. 73%), dry-rolling hybrid rye may reduce DMI and ruminal pH.

Effect of processing method and severity for hybrid fall rye on dry matter intake, ruminal fermentation, and apparent total tract nutrient digestibility in ruminally cannulated beef heifers

This study compared dry-rolled and tempered hybrid rye when processed to a coarse or fine severity on dry matter intake (DMI), ruminal fermentation, and apparent total tract nutrient digestibility for beef cattle. Eight ruminally cannulated Simmental heifers (327 ± 33.1 kg, mean ± SD) were used in a replicated 4 × 4 Latin square (21-day periods with 16 days for adaptation and 5 d collection) balanced for carry-over effects with a 2 × 2 factorial arrangement of treatments. Feeding tempered rye increased ( P = 0.01) DMI when compared to dry-rolled rye, but there was no effect of processing severity. Cattle fed dry-rolled rye had a greater ( P = 0.04) area that pH was &lt;5.5 when compared to those fed tempered rye. Feeding dry-rolled rye increased dry matter digestibility ( P = 0.02) and crude protein digestibility ( P = 0.01) when compared to tempered rye, and there was a greater effect to increase total tract starch digestibility with increasing severity of processing for tempering than for dry rolling (interaction, P = 0.03). In conclusion, tempered hybrid rye processed to a fine severity may result in similar total tract starch digestibility to dry-rolled hybrid rye without the marked reductions in DMI and ruminal pH.

Effect of vitamin blend supplementation on the ingestive, digestive, and ruminal parameters of Nellore cattle

Rumen cannulated Nellore bulls (n = 4) were used in a 4 × 4 Latin square design, with a 2 × 2 factorial scheme to evaluate the effects of vitamin supplementation on: (1) ingestive, digestive, and ruminal parameters; (2) serum concentrations of 25-hydroxyvitamin D (25(OH)D); and (3) in situ degradability of complete diets. The factors consisted of two fat-soluble vitamin blend (ADE) supplementation levels (ADE− or ADE+) and two B vitamin blend (biotin, niacin, and thiamine) supplementation levels (B-blend− or B-blend+). Thus, the treatments evaluated consisted of no vitamin supplementation (ADE− B-blend−), supplementation of a B vitamin blend (ADE− B-blend+), supplementation with a fat-soluble vitamin blend (ADE+ B-blend−), or a combination of these two blends (ADE+ B-blend+). Nutrient intake and DM, as well as ruminal digestibility were not affected (P > 0.05) by any of the vitamin supplementations. The apparent total-tract digestibility of DM, organic matter (OM), neutral detergent fiber corrected for residual ash and protein (apNDF), crude protein (CP), and non-fiber carbohydrates (NFC) were not influenced by the experimental diets (P > 0.05). Furthermore, an increase in starch total-tract digestibility was verified with ADE supplementation in the diets (P = 0.031). None of the in situ parameters were affected (P > 0.05) by vitamin supplementation. Further, the treatments did not affect ruminal kinetics (ki, kp, and kd,) of DM, OM, and starch (P > 0.05). The omasal flow of total N, NH3-N, non-ammonia N, microbial N, and non-ammonia non-microbial N (P > 0.05) or the efficiency of microbial protein synthesis (P > 0.05) were not affected by vitamin blend supplementation. The total fat volatile acid (VFA) concentrations, as well lactate concentration were not affected (P > 0.05) by vitamin blend supplementation. Bulls that consumed the combination of ADE and B-blend supplementation had lower ruminal NH3-N concentrations (P = 0.008). B-blend vitamin supplementation decreased ruminal pH (P = 0.003). As expected, concentrations of serum 25(OH)D increased (P = 0.001) in Nellore bulls fed diets with the combination of fat-soluble vitamin (ADE) and B-blend supplementation. Supplementing Nellore bulls with a vitamin blend containing 25(OH)D3 was a successful strategy for increasing circulating concentrations of 25(OH)D. The B vitamin blend (biotin, niacin, and thiamine) supplementation did not improve ruminal fermentation, ingestive or digestive parameters. However, the fat-soluble vitamin blend (ADE) supplementation increased total-tract starch digestibility.

Meta-analysis of the effects of the dietary application of exogenous alpha-amylase preparations on performance, nutrient digestibility, and rumen fermentation of lactating dairy cows.

Several studies have evaluated the effects of the dietary application of exogenous alpha-amylase preparations (AMA) as a strategy to increase total tract starch digestibility (TTSD) and milk yield (MY) in dairy cows, but the results have been inconsistent. Thus, the objective of this study was to evaluate the effects of the dietary application of AMA on the performance, digestibility, and rumen fermentation of lactating dairy cows using a meta-analytic method. A total of 18 peer-reviewed manuscripts (N = 32 treatment comparisons) from 2003 to 2019 were systematically identified following the PRISMA method. The weighted raw mean differences between dietary AMA and control treatments were compared with a robust variance estimation. Likewise, diet characteristics like crude protein (CP) content, NDF content, starch content, days in milk (DIM), experimental design (Latin square and continuous), and AMA dose (0 to 732 Kilo Novo units [KNU]/kg TMR) were used as covariates in a meta-regression, subgrouping, and dose-response analysis. Compared to the control, dietary AMA increased (P < 0.05) DM digestibility (69.32% vs. 68.30%), TTSD (94.62% vs. 94.10%), milk protein concentration and yield (3.11% vs. 3.08%; 1.14 vs. 1.10 kg/d) and tended to increase (P = 0.09) fat-corrected milk (35.96 vs. 35.10 kg/d), but no effects were observed on DM intake (22.99 vs. 22.90 kg/d) and feed efficiency (1.50 vs. 1.48). Dietary AMA tended (P = 0.10) to reduce rumen pH (6.27 vs. 6.30). Both the enzyme dose and DIM strongly influenced (P < 0.05) the effects of AMA on digestibility and performance. The dose-response analysis revealed that feeding 600 KNU/kg to high-producing early lactation (< 70 DIM) dairy cows increased FCM and milk protein. Accounting for the type of experimental design was associated with a lower between-studies-variance among comparisons. Overall, this meta-analysis supports the hypothesis that dietary AMA supplementation is associated with a better lactational performance in dairy cows. However, these effects are only suitable for high-producing early lactation dairy cows.

Effects of rumen-protected leucine on production performance and starch digestion in the small intestine of lactating goats

This study was conducted to evaluate the effects of rumen-protected leucine (RP-Leu) on production performance and starch digestion in the small intestine of lactating goats. Thirty lactating goats (body weight: 43.07 ± 5.06 kg; first parity, day in milk: 135 ± 15 days; milk yield: 2.06 ± 0.44 kg/d) were randomly assigned into one of the following dietary treatments: (1) CON: basal diet and (2) RPL: basal diet + 10.6 g/d RP-Leu. The experiment lasted 65 days, 15 days for adaption, 45 days for treatment, and 5 days for measurement. Goats fed the diet supplemented with RP-Leu had higher (P < 0.05) average daily gain than those fed the CON diet, but no significant difference (P > 0.05) was observed in milk yield and milk composition. The addition of RP-Leu did not affect dry matter intake, apparent total tract digestibility of starch, and rumen fermentation parameters in lactating goats (P > 0.05). The feces of goats fed the diet supplemented with RP-Leu had reduced molar proportion of butyrate and increased pH and molar proportion of acetate compared with that of goats fed the basal diet (P < 0.05). Dietary supplementation of RP-Leu increased the relative abundance of Christensenellaceae, Christensenellaceae_R-7, Ruminococcaceae, and Ruminococcus in feces, while reducing the relative abundance of Lachnospiraceae and Anaerostipes (P < 0.05). Serum low-density lipoprotein and free leucine were greater (P < 0.05) for goats fed the RPL diet than those of goats fed the CON diet. In addition, the concentrations of total cholesterol and high-density lipoprotein in goats fed the RPL diet tended to be higher (0.05 ≤ P < 0.10) than those of goats fed the CON diet. In conclusion, dietary supplementation of RP-Leu probably improved starch digestibility in the small intestine of lactating goats showing as reduced hindgut starch fermentation and unchanged starch intake, apparent total tract digestibility of starch and rumen fermentation parameters.

Dietary Soluble Non-Starch Polysaccharide Level Influences Performance, Nutrient Utilisation and Disappearance of Non-Starch Polysaccharides in Broiler Chickens.

Simple SummaryNon-starch polysaccharides (NSP) constitute a major part of the dietary fibre component in plant-based feed ingredients, accounting for approximately 10% of the nutrients in a poultry diet. However, NSP are generally not considered during formulation of commercial broiler diets. The functions of dietary NSP in poultry diets, including both the soluble and insoluble fraction, has been extensively researched and discussed. The soluble fraction is of particular interest to poultry nutritionists and producers, as it increases digesta viscosity, affecting nutrient digestion and absorption and thus litter quality. Soluble NSP (sNSP) also provides fuel for beneficial microbiota species. The extent of impact of dietary sNSP level on broiler performance and nutrient utilisation is poorly understood. Consequently, in this study, broilers were fed commercial-type diets with varying sNSP levels, and the effects of the sNSP level on ileal and total tract nutrient digestibility and productive performance were evaluated. The results revealed that even a small variation in dietary sNSP content induces an impact in broilers, particularly in young birds. Thus, sNSP level and composition should be considered during formulation of commercial poultry diets.This study evaluated the effect of dietary soluble non-starch polysaccharides (sNSP) on performance and nutrient utilisation in broilers from d 0 to 35. Cobb 500 broilers (n = 480, 80 birds per treatment) were fed either wheat- or corn-soybean meal-based diets formulated to contain either a high, medium, or low sNSP content, in a 2 × 3 factorial arrangement, fed as Starter (d 0–14) and Grower (d 14–35). Birds fed the low sNSP level presented greater BWG at d 0–14 and lower feed intake at d 14–35 compared to birds fed the medium sNSP level (p < 0.005). At d 14, birds fed the high sNSP level presented greater ileal and total tract starch digestibility and total tract sNSP degradability and insoluble NSP degradability, compared to feeding the low sNSP level. At d 35, total tract DM and metabolisability of gross energy was greater in birds fed the medium sNSP level compared to those fed the high or low sNSP level (p < 0.005). Generally, bird performance and nutrient utilisation was greater in birds fed the corn-based diets compared to the wheat-based diets. These results illustrate that dietary sNSP level and composition influences bird performance and nutrient digestibility.