Apparent Total Tract Digestibility Of DM Research Articles

Scaling-up fungal pretreatment of lignocellulose biomass: Impact on nutritional value, ruminal degradability, methane production, and performance of lactating dairy cows

Scaling-up fungal pretreatment of lignocellulose biomass (LCB) for ruminant nutrition has become a major research challenge in recent years. This study systematically investigated the effectiveness of fungal (Pleurotus ostreatus) pretreatment (for 30 days under solid state fermentation (SSF)) of large quantities (8400 kg) of lime-pasteurized wheat straw, in terms of improvement in nutritional value, in vitro ruminal fermentation characteristics and methane (CH4) production potential. We further investigated the effects of stepwise replacement of untreated wheat straw (UTWS) with the lime pasteurized P. ostreatus treated wheat straw (PTWS) on dry matter intake (DMI), apparent total tract digestibility, production performance, CH4 emission and feed efficiency of lactating dairy cows. The results revealed that PTWS had lower lignin (P< 0.001), hemicellulose (P< 0.001) and cellulose (P< 0.05) contents and higher crude protein (CP; P< 0.001) content and cellulose to lignin ratio (P< 0.01), as compared to UTWS. The PTWS had higher in vitro DM digestibility (IVDMD; P< 0.001), total gas production (IVGP; P< 0.01), total volatile fatty acids (VFAs, P< 0.01) and propionate (P< 0.05) concentration, and lower (P< 0.05) pH and CH4 gas production during 72 h in vitro fermentation. Notably, the fungus degraded 33.3 % lignin at the expense of 6.56 % cellulose, and markedly increased CP content (46.3 %), IVDMD (20.2 %), IVGP (16.8 %) and VFAs (10.0 %) production, and decreased CH4 production (10.3 %). The aflatoxin B1 concentration of PTWS was <5.0 µg/kg, and mycelium concentration was 181.9 mg/kg DM, reflecting safe and effective tretment of the straw. Replacement of 32 % UTWS in total mixed ration with the PTWS, increased DMI (0.84 kg/day; P = 0.01), apparent total tract DM digestibility (5.5 g/100 g; P< 0.05) and milk yield (1.17 liter/day; P= 0.032), and decreased CH4 emission (1.45 g/kg DMI; P< 0.05). In conclusion, hydrated lime can replace traditional high-tech pasteurization methods for the fungal pretreatment of LCB, and present prospects for scaling up the process for ruminant nutrition.

Supplementing flaxseed meal with sucrose, flaxseed oil, or both: Effect on milk enterolactone, ruminal microbiota profile, production performance, and nutrient utilization in dairy cows

Flaxseed is the richest source of secoisolariciresinol diglucoside, which is converted by ruminal microorganisms primarily to the mammalian lignan enterolactone. Our objective was to investigate the effect of diets containing soybean meal or flaxseed meal (FM) supplemented with sucrose, flaxseed oil, or both on milk enterolactone concentration and yield, diversity and relative abundance of ruminal bacterial taxa, ruminal fermentation profile, production performance, milk fatty acid (FA) yield, and nutrient utilization in dairy cows. Sixteen Holstein cows [8 multiparous (4 ruminally-cannulated) and 8 primiparous] averaging (mean ± SD) 134 ± 54.1 DIM and 679 ± 78.9 kg of BW in the beginning of the study were assigned to treatment sequences in a replicated 4 × 4 Latin square design. Each experimental period lasted 25 d with 18 d for diet adaptation and 7 d for data and sample collection. Diets were formulated to contain a 60:40 forage:concentrate ratio and included (DM basis): 1) 8% soybean meal and 23% ground corn (SBM), 2) 15% FM, 10.7% ground corn, and 5% sucrose (FLX+S), 3) 15% FM, 15.4% ground corn, and 3% flaxseed oil (FLX+O), and 4) 15% FM, 10.2% ground corn, 5% sucrose, and 3% flaxseed oil (FLX+SO). Compared with SBM, the concentration and yield of milk enterolactone increased in cows fed the FM diets, but did not differ among FLX+S, FLX+O, and FLX+SO. The relative abundances of the phyla Firmicutes, Verrucomicrobiota, and Actinobacteriota and those of the bacterial genera Lachnospiraceae NK3A20 group, Eubacterium coprostanoligenes group, Anaeromusa-Anaeroarcus, WCHB1-41, and p-251-o5 decreased, whereas Prevotella and NK4A214 group increased when comparing SBM against at least 1 diet containing FM. Furthermore, the relative abundances of Firmicutes and Actinobacteriota and those of Prevotella, Lachnospiraceae NK3A20 group, Eubacterium coprostanoligenes group, Acetitomaculum, Lachnospiraceae unclassified, NK4A214 group, and Anaeromusa-Anaeroarcus changed (increased or decreased) across the FLX+S, FLX+O, and FLX+SO diets. However, all these changes in the relative abundance of the ruminal bacterial taxa were not conclusively associated with the effect of diets on milk enterolactone. Diets did not affect ruminal pH and concentrations of NH3-N and total VFA. Dry matter intake and yields of milk, milk fat, and milk true protein all decreased in cows fed FLX+O or FLX+SO. Yields of milk total odd-chain FA, branched-chain FA, total < 16C FA, and total 16C FA all decreased with feeding FLX+O and FLX+SO. The apparent total-tract digestibilities of DM and OM were lowest in the FLX+S and FLX+O diets, with CP and ADF digestibilities lowest in cows receiving FLX+S or FLX+O, respectively. Urinary excretion of total N was lowest with feeding SBM. Contrarily, diets did not affect the urinary excretion of total purine derivatives. In brief, despite the effect of diets on the relative abundance of several ruminal microbiota phyla and genera, we were unable to conclusively associate these changes with increased milk enterolactone in FM-containing diets versus SBM.

Efficacy of a novel multi-enzyme feed additive on growth performance, nutrient digestibility, and gut microbiome of weanling pigs fed corn-wheat or wheat-barley-based diet.

One-hundred-and-ninety-two weanling pigs (6.7kg body weight) were used to evaluate the impact of a carbohydrases-protease enzyme complex (CPEC) on growth performance, nutrient digestibility, and gut microbiome. Pigs were assigned to one of the four dietary treatments for 42 d according to a 2 × 2 factorial arrangement of diet type (low fiber [LF] or high fiber [HF]) and CPEC supplementation (0 or 170mg/kg diet). The LF diet was prepared as corn-wheat-based diet while the HF diet was wheat-barley-based and contained wheat middlings and canola meal. Each dietary treatment consisted of 12 replicate pens (six replicates per gender) and four pigs per replicate pen. Over the 42-d period, there was no interaction between diet type and CPEC supplementation on growth performance indices of pigs. Dietary addition of CPEC improved (P < 0.05) the body weight of pigs at days 28 and 42 and the gain-to-feed ratio of pigs from days 0 to 14. During the entire experimental period, dietary CPEC supplementation improved (P < 0.05) the average daily gain and gain-to-feed ratio of pigs. There were interactions between diet type and CPEC supplementation on apparent total tract digestibility (ATTD) of dry matter (DM; P < 0.01), gross energy (GE; P < 0.01), and neutral detergent fiber (NDF; P < 0.05) at d 42. Dietary CPEC addition improved (P < 0.05) ATTD of DM, GE, and NDF in the HF diets. At day 43, dietary CPEC addition resulted in improved (P < 0.05) apparent ileal digestibility (AID) of NDF and interactions (P < 0.05) between diet type and CPEC supplementation on AID of DM and crude fiber. Alpha diversity indices including phylogenetic diversity and observed amplicon sequence variants of fecal microbiome increased (P < 0.05) by the addition of CPEC to the HF diets on day 42. An interaction (P < 0.05) between diet type and CPEC addition on Bray-Curtis dissimilarity index and Unweighted UniFrac distances was observed on day 42. In conclusion, CPEC improved weanling pig performance and feed efficiency, especially in wheat-barley diets, while dietary fiber composition had a more significant impact on fecal microbial communities than CPEC administration. The results of this study underscores carbohydrase's potential to boost pig performance without major microbiome changes.

155 Efficacy of a Bacterial 6-Phytase on Apparent Total Tract Digestibility of Nutrients and Retention of Phosphorus of Nursery and Growing Pigs

Abstract This study was conducted to determine the efficacy of a bacterial 6-phytase on apparent total tract digestibility (ATTD) of nutrients and retention of phosphorus (P) in nursery and growing pigs. In experiment (Exp.) 1, twelve barrows (initial BW of 8.5 ± 0.3 kg) were individually housed in metabolism crates and were allotted based on a quadruplicate 3 × 3 Latin square design with three treatments and three periods. In Exp. 2, twelve barrows (initial BW of 35.7 ± 1.9 kg) were individually housed in metabolism crates and were allotted following the same experimental design of Exp. 1. The dietary treatments were: positive control (PC): a diet formulated meeting nutrient requirements from NRC (2012); negative control (NC): a diet 0.14% deficient in the Ca and P requirements; and a diet with bacterial 6-phytase at 500 FTU/kg of feed (PHY; Rovabio PhyPlus, Adisseo, France). Each period lasted for eight days, and consisted of a 4-day adaptation period and a 4-day collection period. All pigs were weighed at the end of each period to adjust daily feed allowance. Chromium oxide, at 0.5%, was added as an external marker indicating the start and end of fecal collection. Urine and fecal samples were collected daily and stored until further chemical analysis. Data from both experiments were analyzed using the MIXED procedure of SAS 9.4. Treatments were considered fixed effects, and the individual pig and period were included as random effects. In both experiments, the ATTD of Ca and P, and P retention in PC were greater (P &amp;lt; 0.05) compared with NC. Supplementation of bacterial 6-phytase improved (P &amp;lt; 0.05) ATTD of Ca (45 to 57%) and P (31 to 45%) and P retention (31 to 43%) in nursery pigs, and ATTD of P (44 to 55%) and P retention (42 to 54%) in growing pigs. No differences were detected on the ATTD of DM and CP of nursery and growing pigs among the treatments, and on nitrogen (N) retention for growing pigs. In conclusion, the supplementation of a bacterial 6-phytase improved the ATTD and retention of P in nursery and growing pigs. Results from both experiments indicated that the supplementation of a bacterial 6-phytase in diets for nursery and growing pigs can be a potential alternative to reduce the high levels of inorganic P sources, whereas still increasing the digestibility and utilization of P by nursery and growing pigs.

β-mannanase supplemented in diets saved 85 to 100 kcal of metabolizable energy/kg, supporting growth performance and improving nutrient digestibility in grower pigs

The effects of β-mannanase supplementation in metabolizable energy (ME)-reduced diets containing xylanase-phytase were investigated on growth performance, fecal score, ultra-sounded backfat thickness and loin depth, blood profile, apparent total tract digestibility (ATTD), digesta passage rate, and fecal microbiome in grower pigs (n = 40, 26.09 ± 0.96 kg) randomly assigned within 4 treatments: a control diet containing isolated phytase and xylanase valued at 40 kcal of ME/kg (CD0), CD0 + β-mannanase (0.3 g/kg valued at 30 kcal of ME/kg) (CD70), CD0 + β-mannanase (0.3 g/kg valued at 45 kcal of ME/kg) (CD85), and CD0 + β-mannanase (0.3 g/kg valued at 60 kcal of ME/kg) (CD100). Growth performance was not affected in pigs fed ME-reduced diets containing β-mannanase. Pigs with CD100 had lower serum IL-1β concentration, and higher IL-10 was observed in pigs on CD0 than those fed β-mannanase. Coefficients of ATTD, and ATTD of DM and CP were higher in animals fed CD85 or CD100. Pigs with CD85 had higher alpha diversity richness but lower Firmicutes:Bacteroidota ratio. Acidaminococcaceae and Ruminococcaceae were more abundant in pigs fed CD0, but lower for Christensenellaceae NSJ-63 and NSJ-63 sp014384805. Pigs in CD85 showed higher Bacteroidaceae and Prevotella abundance, and lower for Streptococcaceae and Streptococcus. In conclusion, supplementation of β-mannanase in diets containing xylanase-phytase saved 85 to 100 kcal of ME/kg by supporting growth performance and improving nutrient digestibility in grower pigs.

Feeding amylolytic and proteolytic exogenous enzymes: Effects on nutrient digestibility, ruminal fermentation, and performance in dairy cows

Exogenous enzymes are added to diets to improve nutrient utilization and feed efficiency. A study was conducted to evaluate the effects of dietary exogenous enzyme products with amylolytic (Amaize, Alltech) and proteolytic (Vegpro, Alltech) activity on performance, excretion of purine derivatives, and ruminal fermentation of dairy cows. A total of 24 Holstein cows, 4 of which were ruminally cannulated (161 ± 88 d in milk, 681 ± 96 body weight, and 35.2 ± 5.2 kg/d of milk yield), were blocked by milk yield, days in milk, and body weight, and then distributed in a replicated 4 × 4 Latin square design. Experimental periods lasted 21 d, of which the first 14 d were allowed for treatment adaptation and the last 7 d were used for data collection. Treatments were as follows: (1) control (CON) with no feed additives, (2) amylolytic enzyme product added at 0.5 g/kg diet dry matter (DM; AML), (3) amylolytic enzyme product at 0.5 g/kg of diet DM and proteolytic enzyme product at 0.2 g/kg of diet DM (low level; APL), and (4) amylolytic enzyme products added at 0.5 g/kg diet DM and proteolytic enzyme product at 0.4 g/kg of diet DM (high level; APH). Data were analyzed using the mixed procedure of SAS (version 9.4; SAS Institute Inc.). Differences between treatments were analyzed by orthogonal contrasts: CON versus all enzyme groups (ENZ); AML versus APL+APH; and APL versus APH. Dry matter intake was not affected by treatments. Sorting index for feed particles with size <4 mm was lower for ENZ group than for CON. Total-tract apparent digestibility of DM and nutrients (organic matter, starch, neutral detergent fiber, crude protein, and ether extract) were similar between CON and ENZ. Starch digestibility was greater in cows fed APL and APH treatments (86.3%) compared with those in the AML group (83.6%). Neutral detergent fiber digestibility was greater in APH cows compared with those in the APL group (58.1 and 55.2%, respectively). Ruminal pH and NH3-N concentration were not affected by treatments. Molar percentage of propionate tended to be greater in cows fed ENZ treatments than in those fed CON. Molar percentage of propionate was greater in cows fed AML than those fed the blends of amylase and protease (19.2 and 18.5%, respectively). Purine derivative excretions in urine and milk were similar in cows fed ENZ and CON. Uric acid excretion tended to be greater in cows consuming APL and APH than in those in the AML group. Serum urea N concentration tended to be greater in cows fed ENZ than in those fed CON. Milk yield was greater in cows fed ENZ treatments compared with CON (32.0, 33.1, 33.1, and 33.3 kg/d for CON, AML, APL, and APH, respectively). Fat-corrected milk and lactose yields were higher when feeding ENZ. Feed efficiency tended to be greater in cows fed ENZ than in those fed CON. Feeding ENZ benefited cows' performance, whereas the effects on nutrient digestibility were more pronounced when the combination of amylase and protease was fed at the highest dose.

Effect of increasing dietary fermentable fiber on diet nutrient digestibility and estimation of endogenous phosphorus losses in growing pigs.

Fermentable fiber may increase endogenous losses of phosphorus (EPL) and amino acids (AA), thereby reducing apparent nutrient digestibility. Acacia gum with medium-to-high fermentability and low viscosity was increasingly included in diets to investigate its effect on apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients, gross energy (GE), and standardized total tract digestibility (STTD) of P in growing pigs. A control diet (49% cornstarch; 18% bovine plasma protein) was formulated to measure basal EPL. Three additional diets were formulated to include 2.5%, 5.0%, or 7.5% acacia gum at the expense of cornstarch. Diets contained 16.1% to 17.4% CP and 0.31% to 0.33% total P (DM-basis). The four diets were fed to eight ileal-cannulated barrows (initial BW, 54.6 kg) for four 9 d periods in a double 4 × 4 Latin square. Apparent hindgut fermentation (AHF) was calculated as ATTD minus AID. Feeding increasing acacia gum quadratically affected (P < 0.05) AID of DM, GE, linearly decreased (P < 0.05) ATTD of DM, crude protein (CP), GE, digestible (DE) and predicted net energy (NE) value of diets, and linearly increased (P < 0.001) AHF of DM and GE. Increasing acacia gum did not affect AID and standardized ileal digestibility (SID) of CP and AA. Basal EPL was 377 mg/kg DM intake (DMI) and increasing acacia gum linearly increased (P < 0.05) total tract EPL. Increasing acacia gum linearly decreased (P < 0.05) diet ATTD of P, and STTD of P based on either the calculated EPL or NRC (2012) recommended value (190 mg P/kg DMI). Increasing acacia gum did not affect AID and ATTD of Ca of diets. In conclusion, feeding increasing dietary fermentable, low-viscous acacia gum decreased diet AID and ATTD of DM and GE, but did not affect AID or SID of CP and AA. Increasing acacia gum decreased ATTD of P, which might have been due to increased specific endogenous losses of P in the total tract of growing pigs.

Dietary protein oscillation: effects on digestibility, nutrient balance and estimated microbial protein synthesis in lactating dairy cows

Various studies with growing ruminants report increases in nitrogen use efficiency (NUE) when feeding oscillating (OS) dietary CP, whereas limited research with lactating dairy cows demonstrates a lack of improvement in NUE when feeding OS diets. We hypothesised that a total mixed ration (TMR) delivering OS CP (48-h phases of 134 and 171 g CP/kg DM, respectively) compared to a static CP TMR (ST; 152 g CP/kg DM) would result in similar or increased urinary purine derivative excretion (as a marker of microbial protein synthesis (MPS)) and greater urinary nitrogen excretion in lactating dairy cows. Responses in intake, production, apparent total tract digestibility (ATTD), nutrient balance, and estimated MPS were evaluated using faecal and urine collection in 12 multiparous cows (172 ± 39 d in milk) in a randomised complete block design, where total urinary output was estimated indirectly. All measurements were taken during d 8 (at 1700) to d 16 (at 1700) of the 16-d study that followed a 28-d period in which cows already received their respective treatments. Dry matter intake, yields of milk, protein, fat, lactose, and fat- and protein-corrected milk were similar for ST and OS. Milk composition, BW, and body condition score also did not differ between treatments, except for a tendency for increased milk urea concentration with OS (13.7 vs 12.4 mg/dL). Feed efficiency, NUE and ATTD of organic matter, NDF, CP and gross energy did not differ, but ATTD of crude fat (658 vs 627 g/kg) and starch (980 vs 975 g/kg) increased, and ATTD of DM (702 vs 691 g/kg) tended to increase with OS. Milk energy as a proportion of digested energy tended to decrease with OS (34.6 vs 37.1%), but other energy metabolism variables were not affected by treatment. Estimated urinary nitrogen excretion increased (165 vs 144 g/d), estimated urinary nitrogen as a proportion of nitrogen intake tended to increase (25.3 vs 22.7%), and milk nitrogen as a proportion of digested nitrogen decreased (47.3 vs 51.8%) in response to OS. Estimated urinary excretion of creatinine (184 vs 165 mmol/d), uric acid (29 vs 20 mmol/d) and urea (3.1 vs 2.5 mol/d) increased, but other nitrogen metabolism parameters were not affected by OS. Overall, oscillating dietary CP content did not affect lactational performance, milk NUE, or estimated MPS. However, ATTD of some nutrients increased, postabsorptive energy use for milk synthesis tended to decrease, and estimated urinary nitrogen losses increased with OS.

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.

A time-series effect of phytase supplementation on phosphorus utilization in growing and finishing pigs fed a low-phosphorus diet.

Two experiments were carried out to determine a time-series effect of phytase on phosphorus (P) utilization in growing and finishing pigs using growth performance, apparent total tract digestibility (ATTD) of nutrients, P excretion, and plasma concentrations of minerals as the response criteria for evaluation. In both experiments, treatments were arranged as a 3 × 4 factorial in a randomized complete block design with 3 corn-soybean meal-based diets including a P-adequate positive control (PC), a low-P negative control (NC; no inorganic P), and NC supplemented with phytase at 1,000 FYT/kg (NC + 1,000); and 4 sampling time points at days 7, 14, 21, and 28 in experiment 1, and days 14, 26, 42, and 55 in experiment 2. In both trials, 96 growing pigs with average body weight (BW) of 19.8 ± 1.16 and 49.8 ± 3.21 kg, respectively, were allocated to the 3 diets with 8 replicates pens (4 barrows and 4 gilts) and 4 pigs per pen. In experiment 1, pigs fed the PC had higher (P < 0.01) BW, average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (G:F) when compared with pigs fed the NC. There was an interaction (P < 0.01) between time and diet on the BW and ADG of pigs while a linear and quadratic increase (P < 0.01) was observed with the ADFI and G:F, respectively, over time. Phytase supplementation improved (P < 0.01) all growth performance responses. Pigs fed the PC had greater (P < 0.01) ATTD of P and Ca than pigs fed the NC. There was no interaction effect on the ATTD of nutrients. Phytase addition improved the ATTD of P and Ca over pigs fed the NC. There was an interaction (P < 0.01) between diet and time on the total and water-soluble P (WSP) excreted. There was a quadratic decrease (P < 0.01) in plasma concentration of Ca in pigs over time. In experiment 2, there was a quadratic increase (P < 0.01) in BW, ADG, and G:F of pigs over time. Similarly, the inclusion of phytase improved (P < 0.05) all growth performance parameters except ADFI. A linear increase (P < 0.05) in the ATTD of DM, P, and Ca occurred over time. Phytase inclusion improved (P < 0.01) the ATTD of P and Ca. Plasma concentrations of P were improved by phytase addition. Phytase supplementation of the NC reduced WSP excretion by 45%, 32%, and 35% over the growing, finishing, and entire grow-finish period, respectively. In conclusion, phytase improves the utilization of P in growing and finishing pigs; however, the magnitude of effect on responses may vary over time.

Effect of a novel consensus bacterial 6-phytase variant in grower pigs fed corn-soybean meal-based diets formulated with a full nutrient matrix and no added inorganic phosphorus.

The capacity of a novel consensus bacterial 6-phytase variant (PhyG) to entirely replace dietary inorganic phosphorus (Pi) source in grower pigs fed diets with reduction of calcium (Ca), net energy (NE), and digestible amino acids (AA) was evaluated, using growth performance and apparent total tract digestibility (ATTD) of nutrients as outcome measures. A total of 352 mixed-sex pigs (initial BW 23.4 kg) were randomized to 4 treatments, 8 pigs/pen, and 11 pens/treatment. Diets were corn-soybean meal-based and formulated by phase (grower 1, 25 to 50 and grower 2, 50 to 75 kg BW). The positive control diet (PC) provided adequate nutrients and a negative control diet (NC) was formulated without Pi (1.2 g/kg ATTD P) and reduced in Ca (-0.12 to -0.13 percentage points), NE (-32 kcal/kg), and digestible essential AA (-0.004 to -0.026 percentage points) vs. PC. Two further treatments comprised the NC plus 500 or 1,000 FTU/kg of PhyG. Data were analyzed by ANOVA, mean contrasts and orthogonal polynomial regression. Nutrient reductions in the NC reduced (P < 0.05) average daily gain (ADG) during grower 1 and overall (73 to 136 d of age), increased (P < 0.05) feed conversion ratio (FCR) during grower 1 and overall and tended to reduce (P < 0.1) average daily feed intake (ADFI) during grower 2 and overall, vs. PC. Phytase supplementation improved (P < 0.05) FCR during grower 1, ADG during grower 2 and overall, ATTD of DM and P, and tended to improve DE (P = 0.053) in a linear dose-dependent manner. PhyG at 1,000 FTU/kg resulted in growth performance (all measures, all phases) equivalent to PC. The findings demonstrate that PhyG at 1,000 FTU/kg totally replaced Pi in complex grower pig diets containing industrial co-products, compensated a full nutrient matrix reduction and maintained performance.

96 Nutrient Digestibility of Toasted Soybean Meal and Untoasted Soybean Meal Extruded at Different Temperatures by Weanling Pigs

Abstract The apparent and standardized ileal digestibility (AID and SID) of AA and CP and the apparent total tract digestibility (ATTD) of toasted soybean meal (SBM) and untoasted soybean meal (USM) extruded at 86°C (USM86), 120°C (USM120) and 149°C (USM149) were evaluated. USM was extruded mixed with corn starch (396.5g/kg USM and 603.5g/kg corn starch) in a single-screw extruder (MEX 250, Manzoni, Campinas, Brazil). Thirty-six barrows (7.69±0.89 kg BW) were fed a N-free diet, or four diets composed of 30% of each ingredient, as the only source of N, substituting for starch in N-free diet. Pigs were fed at 2.8 x maintenance (2.8 x 106 kcal digestible energy/kg BW0.75) for 10 days (5 d adaptation, 5 d feces collection), and on day 11 piglets were euthanized for ileal digesta collection. A randomized block design was used, with 8 replicates, using the pig as the experimental unit. ANOVA was performed and means were separated using Tukey test (5%). Increasing extrusion temperatures reduced trypsin inhibitors concentrations from 28.24 in USM to 3.51, 1.37, and 1.12 mg/g CP in USM86, USM122, and USM137, respectively, and 2.37 mg/g CP was found in SBM. USM86 showed lower (P &amp;lt; 0.05) ATTD of DM (8–13%), GE (2–4%), and CP (12–16%) compared to SBM, USM120 and USM149, which did not differ (P &amp;gt;0.05). The ATTD of EE of SBM was 17–19% higher (P &amp;lt; 0.05) than of USM86 and USM120, which were similar (P &amp;gt; 0.05) to each other and greater (P &amp;lt; 0.05) than that of USM149. Extrusion at 86oC was insufficient to inactivate anti-nutritional factors and resulted in reductions (P &amp;lt; 0.05) of 25–29% and 27–31% in CP and AA AID and SID compared to SBM, USM120, and USM149, which were, in general, similar (P &amp;gt; 0.05). Soybean meal extruded at 120 and 139°C presented a similar nutritional value to toasted soybean meal.

Postpartum responses of dairy cows supplemented with cereal grain or fibrous by-product concentrate

The present study examined the effect of replacing cereal grain with a fibrous by-product concentrate on nutrient intake, milk production traits and fatty acid composition, diet digestibility, feed conversion efficiency (FCE), CH4 and CO2 emissions, and plasma blood parameters of dairy cows in early lactation. Twenty-two Nordic Red cows were randomly assigned to one of two dietary treatments immediately after calving until 18 weeks in lactation. The cereal grain treatment contained 593 g/kg of grass silage, 317 g/kg of cereal grain mixture (barley, oat, and wheat), 79 g/kg of heat-treated rapeseed meal, and 11 g/kg of a mineral mix on a DM basis. A mixture of unmolassed beet pulp, wheat middlings, barley fibre, and wheat bran replaced cereal grains in the by-product treatment. The diets were isocaloric and isonitrogenous and were fed ad libitum as total mixed rations. The by-product diet had a higher fibre content, while starch content was reduced compared with the cereal grain diet. Despite the 12 %-unit difference in dietary starch content, no differences in DMI were observed. Similarly, no differences in body weight and body condition score (BCS) were observed between treatments. Cows fed the fibrous by-product diet had lower apparent total-tract digestibility of DM (683 g/kg), organic matter (700 g/kg), and crude protein (665 g/kg) compared to those fed cereal grain diet (735, 749, and 699 g/kg, respectively), but milk yield and composition, as well as FCE were not affected by treatment. The edible feed conversion ratio in the by-product group was on average 3.7- folds higher than the cereal grain group. Total CH4 emission (g/d) and CH4 yield (g/kg DMI) reduced by 10.3% on average when by-product replaced cereal grains, but CH4 intensity (g CH4/kg ECM) was not significantly influenced by diet. Although the feeding of by-product had no effect on milk fat content, it changed its fatty acid profile by increasing the proportion of some unsaturated fatty acids (ƩC18:1 trans, C18:3 cis-9 cis-12 cis-15, omega-3) in milk fat. Replacing cereal grain with fibrous by-product in the diets of early lactation dairy cows had no effect on their risk of developing metabolic disorders. These findings suggest that cows fed grass silage-based diets can be supplemented with fibrous by-product concentrates without affecting feed efficiency or energy balance status, thereby supporting sustainable food production. However, future works should evaluate the economic aspects of feeding by-product concentrates to determine their practical application for feed manufacturers and farmers.

Effects of ractopamine hydrochloride on nutrient digestibility and nitrogen excretion of finishing beef cattle.

The objective was to quantify the effects of the beta-adrenergic agonist (β-AA) ractopamine hydrochloride (Actogain, Zoetis, Parsippany, NJ) on nitrogen excretion and nutrient digestibility in feedlot cattle. In experiment 1, 12 Simmental × Angus steers were blocked by bodyweight (531 ± 16 kg) and used in a randomized complete block design. Dietary treatments included: 1) a control without β-AA (CON) or 2) 400 mg/steer/d ractopamine hydrochloride (RAC) for 35 d before slaughter. Diets contained (DM basis) 55% dry-rolled corn, 20% corn silage, 15% modified wet distillers grains with soluble, and 10% supplement. For each block, total collection of feed, orts, feces, and urine were conducted for two 5 d sampling periods during week 2 and 4 of RAC supplementation. No interaction (P > 0.21) between treatment and collection period was observed for any parameter evaluated. Dietary treatment had no effect (P = 0.51) on DMI, but RAC had decreased fecal DM output (P = 0.04) compared with CON. Thus, RAC had greater apparent total tract DM digestibility (77.2 vs. 73.5%; P < 0.01), N digestibility (72.4 vs. 69.4%; P = 0.01), and NDF digestibility (65.6 vs. 60.2%; P < 0.01) than CON. Although treatment did not affect nitrogen intake (P = 0.52), RAC tended to reduce total nitrogen excretion (113.3 vs. 126.7 g/d; P = 0.10) compared with CON due to a tendency for decreased fecal nitrogen output (53.9 vs. 61.3 g/d; P = 0.10). However, dietary treatment had no effect (P = 0.53) on urinary nitrogen output or percentage of urinary nitrogen excreted as urea (P = 0.28). Experiment 2 was an in vitro experiment conducted to validate the effects of RAC on nutrient digestibility using Simmental × Angus heifers (451 ± 50 kg). Rumen fluid was collected individually by stomach tube from CON- (n = 9) and RAC-fed (n = 10) heifers to inoculate bottles containing a CON or RAC-containing substrate in a split–plot design. No interaction between rumen fluid source and in vitro substrate was observed. Greater IVDMD (P = 0.01) was observed in rumen fluid from RAC-fed heifers compared with rumen fluid from CON-fed heifers. The inclusion of RAC in the in vitro substrate increased IVDMD (P < 0.01). Overall, feeding RAC increased microbial digestion of the dry-rolled corn-based finishing diet to increase total tract dry mater digestion by 5% and reduce nitrogen excretion by 10.6% in the 35 d period prior to slaughter.

PSII-17 Comparison of corn ethanol co-products from Brazil and USA apparent total tract digestibility of nutrients in pigs

Abstract The objective of this study was to determine the apparent total tract digestibility (ATTD) of DM, GE, EE, NDF, ADF, and CP, the metabolizability of energy, of two high protein (HP) corn distillers dried grain (DDG) and of two corn DDG with solubles (DDGS), from Brazil and USA, and their respective digestible and metabolizable energy content in growing pigs. Fifty crossbred barrows (32.4±6.9kg) were distributed in a randomized block design, with 10 replicates, and received a 96.7 % corn basal diet (BD) or four diets with 40% of each test ingredient: Brazilian HP DDG (BHP); USA HP DDG (UHP); Brazilian DDGS (BDG) and USA DDGS (UDG), substituting for corn. Animals were fed at 2.8 x maintenance (110 kcal of DE per kg of BW0.75) for 7 d adaptation and 4 d of total feces and urine collection. The ATTD of nutrients and energy were calculated by difference and the results were submitted to ANOVA and Tukey’s test (P&amp;lt; 0.05). The BHP and UHP samples contained (as is basis) 92.3 – 89.6% DM, 2.8 – 3.5% ash, 42.9 – 34.9% CP, 10.3 – 7.3% EE, 32.7 – 47.5% NDF, 13.3 – 17.5% ADF, 5.30 – 4.90 Mcal/kg, respectively. The BDG and UDG samples contained (as is basis) 86.1 – 86.1% DM, 4.8 – 4.9% ash, 13.9 – 25.8% CP, 9.0 – 6.4% EE, 40.8 – 40.2% NDF, 13.3 – 14.3% ADF, 4.51 – 4.53 Mcal/kg, respectively. The ATTD of DM and GE and the digestible and metabolizable energy contents of BHP were greater (P&amp;lt; 0.05) than those verified in UHP. The ATTD of DM, GE, NDF, ADF, digestible and metabolizable energy values of BDG were lower (P &amp;lt; 0.05) than those verified in UDG. In conclusion, the BHP presented higher digestible values to almost all parameters evaluated, however, all ingredients presented acceptable digestible contents, indicating they may be used in pigs feeding.

181 Effects of Aspergillus oryzae prebiotic on energy and nutrient digestibility of growing pigs

Abstract The objective of this study was to determine the effects of an Aspergillus oryzae prebiotic (AOP, Amaferm®) on nutrient digestibility in growing pigs fed high fiber diets. Eighteen growing barrows (initial BW = 50.60 ± 4.90 kg) were surgically equipped with a T-cannula at the distal ileum. Three diets were formulated by including 29.65% corn-distillers dried grains with solubles (DDGS), 36.65% rice bran (RB) or 24.59% wheat middlings (WM) in corn and soybean meal-based diets to meet nutrient requirements for 50 to 75 kg growing pigs. Three additional diets were formulated by supplementing 0.05% AOP at the expense of corn in DDGS (DDGS + AOP), RB (RB + AOP), and wheat middlings (WM + AOP) diets. Pigs were allotted randomly to a triplicated 6 × 2 Youden square design with 6 diets and 2 successive periods. Feces and ileal digesta were collected for 2 d after a 21 d adaptation period, and nutrient content was analyzed to calculate apparent total tract digestibility (ATTD) and apparent ileal digestibility (AID). Standardized ileal digestibility (SID) of amino acids was calculated by correcting AID with basal endogenous amino acid losses determined from the same set of pigs. Supplementation of 0.05% AOP increased (P &amp;lt; 0.05) ATTD of DM, GE, CP, NDF, and ash in DDGS, RB, and WM diets. Diet DE was 35 kcal/kg greater (P &amp;lt; 0.05) in pigs fed AOP supplemented diets compared with those fed diets without AOP. Pigs fed DDGS+AOP diet had greater (P &amp;lt; 0.05) AID of ether extract compared to those fed DDGS diet. However, supplementation of AOP did not (P &amp;gt; 0.05) affect AID of GE, DM, CP, NDF, ash or SID of amino acids. In conclusion, supplementation of AOP in high fiber diets containing DDGS, RB, or WM increased total tract energy value and nutrient digestibility.

172 Increasing inclusion of fermentable fiber decreases nutrient digestibility in grower pigs

Abstract Fermentable fiber may increase endogenous losses of P and AA, thereby reducing apparent nutrient digestibility. Acacia gum fiber with medium-to-high fermentability and low viscosity was used to investigate its effect on apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients, and standardized total tract digestibility (STTD) of P in grower pigs. A P-free basal diet (49% corn starch; 18% bovine plasma protein) was formulated to measure basal endogenous P losses (EPL). Three diets were formulated to include 2.5, 5.0, or 7.5% acacia gum fiber at the expense of corn starch in the P-free basal diet. Diets contained 16.1–17.4% CP and 0.31–0.33% total P (DM-basis). The 4 diets were fed to 8 ileal-cannulated barrows (initial BW, 54.6 kg) for four 9-d periods in a double 4 × 4 Latin square. Apparent hindgut fermentation (AHF) was ATTD minus AID. Increasing inclusion of acacia gum quadratically decreased (P &amp;lt; 0.01) AID of DM (∆ 11.1%), linearly decreased (P &amp;lt; 0.05) ATTD of DM (∆ 1.7%) CP (∆ 1.2%), and quadratically increased (P &amp;lt; 0.05) AHF of DM (∆ 9.4%). Basal EPL were 391 and 377 mg/kg DM intake (DMI) for ileum and total tract, respectively. Increasing inclusion of fiber linearly increased (P &amp;lt; 0.05) ileal EPL (∆ 184 mg/kg DMI), and tended to linearly increase (P &amp;lt; 0.10) EPL for total tract (∆ 243 mg/kg DMI). Dietary inclusion of acacia gum tended to linearly decrease (P &amp;lt; 0.10) AID of P, but did not affect (P &amp;gt; 0.10) ATTD, or STTD of P. In conclusion, increasing inclusion of fermentable, low viscous acacia gum fiber decreased diet digestibility of DM and ATTD of CP, but did not affect total tract P digestibility, indicating that increasing fermentable fiber did not increase specific endogenous losses of P in the total tract.

Increasing calcium from deficient to adequate concentration in diets for gestating sows decreases digestibility of phosphorus and reduces serum concentration of a bone resorption biomarker.

The objective of this experiment was to test the hypothesis that the concentration of Ca in diets fed to late gestating sows affects the apparent total tract digestibility (ATTD) and retention of Ca and P, serum concentrations of Ca and P, hormones, and blood biomarkers for bone formation and resorption. Thirty-six sows (average parity = 2.8) were housed in metabolism crates from day 91 to day 104 of gestation and fed 1 of 4 experimental diets containing 25, 50, 75, or 100% of the requirement for Ca. All diets met the requirement for P. The initial 5 d of each period were the adaptation period, which was followed by 4 d of quantitative collection of feces and urine. At the end of the collection period, a blood sample was collected from all sows. Results indicated that feed intake, weights of dried fecal and urine samples, and the ATTD of DM were not affected by dietary Ca, but ATTD of Ca increased (quadratic, P < 0.05) as Ca in diets increased. Urine Ca output was not affected by dietary Ca, but Ca retention increased (quadratic, P < 0.05) as Ca intake increased. Fecal P output increased (linear, P < 0.001) as dietary Ca increased, which resulted in a linear decrease (P < 0.001) in the ATTD of P. Urine P output also decreased (linear, P < 0.001) as dietary Ca increased, but P retention increased (linear, P < 0.05). Regressing the apparent total tract digestible Ca against dietary Ca intake resulted in a regression line with a slope of 0.33, indicating that true total tract digestibility of Ca in calcium carbonate was 33%. Serum concentrations of Ca and P and estrogen, calcitonin, and parathyroid hormone were not affected by dietary Ca. Serum concentration of carboxyterminal cross-linked telopeptide of type I collagen (CTX-I) decreased (linear, P < 0.05) as dietary Ca increased, which is a result of reduced bone resorption as dietary Ca increased. Serum bone-specific alkaline phosphatase tended to decrease (linear, P < 0.10) as Ca in diets increased, but the concentration of osteocalcin (OC) in serum was not affected by dietary Ca. The ratio between OC and CTX-I tended to increase (P < 0.10) as dietary Ca increased, which indicated that there was more bone formation than resorption in sows as dietary Ca increased. In conclusion, P digestibility in late gestating sows decreased, but retention of P increased, as dietary Ca increased from inadequate to adequate levels and blood biomarkers for bone resorption changed as Ca and P retention increased.

Net absorption and liver metabolism of amino acids and heat production of portal-drained viscera and liver in multiparous sows during transition and lactation

BackgroundDetermination of nutrient requirements in the late gestating and lactating sows is essential to optimize sow productivity. The objectives of the present study were to quantify amino acid (AA) fluxes and heat production across portal-drained viscera (PDV) and liver in multiparous sows during transition and lactation.MethodsEight second parity sows were fitted with indwelling catheters in the femoral artery and in the mesenteric, portal and hepatic veins. Eight hourly sets of blood samples were taken starting 0.5 h before feeding at − 10, − 3, + 3, and + 17 d in milk (DIM). Blood gases, plasma metabolites and apparent total tract digestibility (ATTD) of nutrients were measured.ResultsFeed intake, the ATTD of DM, energy, nitrogen, fat and crude fiber changed with DIM (P < 0.001). Except for Glu, O2, and urea, all net portal fluxes were positive, and all were affected by DIM (P < 0.05) and by sampling time (P < 0.01). Compared with pre partum levels, net portal uptake of AA was 3-63% lower at + 3 DIM but 40-100% higher at + 17 DIM. Net portal fluxes of AA peaked at 1.5 to 2.5 h after feeding except for Glu, and they were positively correlated with changes in sow feed intake across DIM. The net portal recovery was low for Met (49%), Thr (54%), and His (54%) and high for the remaining essential AA (63-69%) and none of them differed across DIM. Net hepatic uptake (i.e. hepatic oxidation) of Lys, Thr, Ile, Leu and Phe peaked at 0.5 to 2.5 h after feeding, whereas uptake of Trp, Val, and His was constant, while that of Met was close to zero.ConclusionThe net portal recovery was substantially lower for Met, Thr, and His than the remaining essential AA. Hepatic AA oxidation peaks 0.5 to 2.5 h after feeding. The heat production in PDV and liver was approximately two-fold higher at peak lactation compared to other stages. The study suggests that lysine was the limiting AA in peak lactation but not in early lactation.

Effects of betaine and rumen-protected folic acid supplementation on lactation performance, nutrient digestion, rumen fermentation and blood metabolites in dairy cows

This study evaluated the effects of betaine (BT) and rumen-protected folic acid (RPFA) on lactation performance, nutrient digestion, rumen fermentation and blood metabolites in dairy cows. Thirty-six mid-lactation Holstein dairy cows were assigned to one of four treatments in a 2 × 2 factorial randomized block design. Supplemental RPFA (0 [RPFA-] or 5.2 mg/kg dietary dry matter [DM] of folic acid [FA] from RPFA [RPFA+]) and BT (0 [BT-] or 4.0 g/kg DM of BT [BT+]) was mixed into the daily ration, respectively. The experiment lasted for 105 days with the first 15 days for adaptation and the following 90 days for sample collection. The RPFA × BT interaction was significant for blood folate concentration which decreased with BT addition in RPFA- diet but increased with BT addition in RPFA + diet. Dry matter intake and body weight change were similar among treatments. Dietary RPFA or BT addition increased yield of milk and milk fat but higher milk protein yield was only observed for RPFA addition. Feed efficiency was increased due to RPFA or BT addition. Apparent total-tract digestibility of DM, organic matter, crude protein, neutral detergent fibre and acid detergent fibre increased with RPFA or BT addition. Ruminal pH decreased with RPFA addition but was unchanged with BT addition. Dietary RPFA or BT addition increased ruminal total volatile fatty acids concentration and altered rumen fermentation mode to more acetate production. Ammonia-N concentration was unchanged with RPFA addition but decreased with BT addition. Addition of RPFA or BT increased activity of carboxymethyl-cellulase, xylanase and protease as well as population of total bacteria, protozoa, Ruminococcus (R.) albus and R. flavefaciens. Population of Prevotella ruminicola was higher for RPFA addition but activity of cellobiase and population of total fungi and Ruminobacter amylophilus was higher for BT addition. Blood concentrations of glucose, non-esterified fatty acid, beta-hydroxybutyrate and homocysteine were similar among treatments. Blood total protein and albumin concentrations were increased with RPFA addition but were not affected by BT addition. The data indicated that addition of RPFA or BT had beneficial impacts on lactation performance, nutrient digestion and ruminal fermentation and BT addition might increase FA utilization efficiency in dairy cows receiving diet without RPFA.