Total Tract Nutrient Digestibility Research Articles

Effect of thymol on the efficiency of feed utilization and compensatory growth in severe feed-restricted lambs.

The present study aimed to evaluate the effect of thymol on growth performance and apparent total tract digestibility of nutrients in severely feed-restricted lambs. Twenty-one male Baluchi lambs were randomly blocked by live weight into three groups: control without feed restriction (CON), feed restricted (FR), and feed restricted plus thymol (FR + T). The lambs underwent a four-week feed restriction period followed by four weeks of realimentation. Thymol was administered daily to the FR + T group during the feed restriction period. Average daily gain (ADG), average daily feed intake, feed efficiency (FE), partial efficiency of maintenance (PEM), and residual feed intake (RFI) were measured as growth performance parameters. Results showed that the severe feed restriction had adverse effects on ADG and FE, but improved PEM (P < 0.05). The effects of thymol administration on ADG, FE, PEM, and apparent total tract digestibility were not significant (P > 0.05). However, the lambs that received thymol during the feed restriction period showed a negative RFI during realimentation (P < 0.05). Overall, these findings suggest that feed restriction as well as thymol may have the potential to improve efficiency of feed utilization in growing lambs. However, this positive effect is independent of the improvement in nutrient digestibility.

Organic acid preservation of cereal grains improves grain quality, growth performance, and intestinal health of post-weaned pigs

This study investigated the effect of preserving wheat and barley grains with an organic acid liquid surfactant mould inhibitor compared to conventional artificial drying and assessed its effects on the health and performance of pigs post-weaning (PW). A 2 × 2 factorial arrangement was conducted to investigate the interaction between grain preservation method (dried vs. preserved) and zinc oxide (ZnO) inclusion (yes vs. no) on growth performance, diarrhoea scores and incidence, and total tract nutrient digestibility. One hundred and ninety-two pigs (3 pigs/pen;16 replicates/treatment) were assigned to one of four experimental diets for 35 days: (1) dried grain diet, (2) preserved grain diet, (3) dried grain diet with ZnO and (4) preserved grain diet with ZnO. Diets were formulated to contain similar levels of net energy and standardised ileal digestible lysine. On day 35 PW, 24 pigs (12 replicates/treatment) from the non-ZnO supplemented groups were euthanised and digesta was collected for coefficient of apparent ileal digestibility (CAID), gut microbial population and volatile fatty acid analysis. Stomach tissue was also collected for gene expression analysis, as well as small intestine samples for gut morphology. Notable improvements in grain quality were observed in the preserved grain, including a reduction in grain pH, mould presence, and contamination by mycotoxins, specifically deoxynivalenol in wheat and barley, and ochratoxin A and HT-2 toxin in barley. The preserved grain diet improved average daily gain (ADG; P<0.01) and body weight (BW; P<0.01) compared to the dried grain diet. The incorporation of ZnO increased average daily feed intake (ADFI; P<0.01) and BW (P<0.05) in the dried grain diet, however, ZnO did not affect ADFI (P>0.05), and reduced ADG and BW in the preserved grain diet (P<0.05). Pigs offered the preserved grain diet had reduced faecal scores and diarrhoea incidence compared to those offered the dried grain diet (P<0.05). Supplementation of ZnO reduced faecal scores and diarrhoea incidence compared to non-supplemented pigs (P<0.001). On day 35 PW, the preserved grain diet had improved CAID of nitrogen and gross energy (P<0.05), lower levels of colonic branched-chain volatile fatty acids (P<0.05), and beneficial shifts in gut microbial populations. Specifically, there was a reduction in ileal Streptococcus (P<0.001) and an increased abundance of colonic Faecalibacterium (P<0.05). In conclusion, organic acid preservation improved grain quality, benefiting post-weaned pigs through improved nutrient digestibility and gut health, thus enhancing overall growth performance PW.

Effect of forage quality and narasin inclusion on ruminal fermentation, nutrient intake, and total tract digestibility of Nellore steers.

The study aimed to evaluate the effects of forage quality and narasin inclusion on intake, digestibility, and ruminal fermentation of Nellore steers. Twenty-eight rumen-cannulated Nellore steers (initial body weight [BW] = 350 ± 32.4kg) were allocated to individual pens in a randomized complete block design, with 7 blocks, defined according to the fasting BW at the beginning of the experiment. The steers were randomly assigned within blocks to 1 of 4 experimental diets in 2 × 2 factorial arrangements, being the first-factor forage quality (MEDIUM = 81g of CP/kg of dry matter [DM], and HIGH = 153g of CP/kg of DM), and the second factor was the inclusion (N13 = diet plus 13mg/kg of DM of narasin) or not (N0) of narasin (Zimprova; Elanco Animal Health, São Paulo, Brazil). The experiment consisted of a 28-d period with 22 d for adaptation and the last 6d for data collection. No haylage quality × narasin interaction (P ≥ 0.68) was observed on DM and nutrient intake. Haylage quality affected (P ≤ 0.01) DM intake, with greater values observed for steers fed HIGH compared with MEDIUM haylage. There was an increase (P < 0.001) in OM, NDF, hemicellulose, and CP intake for steers consuming HIGH vs. MEDIUM haylage. Including N13 did not affect (P > 0.39) DM and nutrient intake of steers. No haylage quality × narasin interactions were detected (P ≥ 0.60) for total tract nutrient digestibility. However, steers fed with HIGH haylage showed an increase (P > 0.001) in DM and digestibility of all nutrients compared with MEDIUM. Steers fed a MEDIUM haylage had a greater (P < 0.01) proportion of acetate compared with steers fed HIGH during all evaluated hours. Steers fed HIGH haylage had a greater (P < 0.01) proportion of propionate at 0h compared with steers consuming MEDIUM, whereas at 12h, steers consuming MEDIUM hay had a greater (P < 0.01) proportion of propionate vs. HIGH haylage. A haylage quality × narasin and haylage quality × time of collection interactions were detected (P ≤ 0.03) for rumen ammonia concentration, which was reduced (P < 0.03) in N13 vs. N0 steers consuming HIGH haylage. Collectively, high-quality haylage allows increased consumption and digestibility, with more energy-efficient ruminal fermentation. In addition, narasin might be an important nutritional tool in forage-based diets to enhance the ruminal fermentation parameters of Bos indicus Nellore steers.

Standardized total tract digestibility of phosphorus in canola meal fed to gestating or lactating sows without or with a multi-enzyme complex

An experiment was conducted to determine coefficients of standardized total tract digestibility (CSTTD) of P in canola meal (CM) fed to gestating and lactating sows without or with a multi-enzyme complex (MC). Eight sows cannulated on day 40 of gestation were assigned at random to the 4 dietary treatments in a replicated 4 × 4 Latin square design. The 4 diets included 2 cornstarch-based diets with 313g/kg solvent-extracted CM as the only source of P, without or with MC, a casein-cornstarch diet to determine ileal endogenous amino acid losses (amino acid digestibility data reported elsewhere), and a P-free diet to determine the endogenous P losses. All diets contained 3g/kg titanium dioxide as an indigestible marker. Gestating sows were fed 3.0kg/day, whereas, during lactation, sows had ad libitum access to diets. Samples were collected over 3 phases; mid-gestation, late-gestation, and lactation. Each phase had 4 experimental periods lasting 8 days. In each period, after 5-day acclimation to the experimental diets, fecal samples were collected by grab sampling via rectal palpation on day 6. Results indicated no differences in total tract digestibility of nutrients between mid-gestation, late-gestation, and lactation. Enzyme supplementation improved (P < 0.05) the apparent total tract digestibility of dry matter and P, and CSTTD of P during lactation. The CSTTD of P in CM was 0.445 (without MC) and 0.504 (with MC) in mid-gestation, 0.455 (without MC) and 0.492 (with MC) in late-gestation, and 0.442 (without MC) and 0.489 (with MC) in lactation. In conclusion, the average CSTTD for P in CM fed to sows was 0.447 and MC significantly improved the CSTTD of P in CM during lactation.

Effects of feeding sulfate trace minerals above recommendations on nutrient digestibility, rumen fermentation, lactational performance, and trace mineral excretion in dairy cows

Most trace minerals (TM) are fed above dairy cow requirements in commercial herds but their fate and effects on dairy cows have not been well documented. In this study, we evaluated the effects of feeding short-term sulfate TM above recommendations on apparent total-tract digestibility of nutrients, rumen fermentation characteristics, serum concentrations, milk yield and composition as well as milk, fecal, and urinary TM excretion in mid-lactation dairy cows. Eight multiparous Holstein cows [average body weight: 684 (SD: 29) kg at 82 (SD: 10) days in milk] in a quadruple 2 × 2 crossover design were fed a basal diet, differing in sulfate TM supplement concentrations, to provide either 0.11, 17, and 63 (control; CON) or 0.95, 114, and 123 (high trace minerals; HTM) mg of dietary Co, Mn, and Zn/kg of dry matter, respectively. Each experimental period had a 21-d adaptation to the diet, followed by a 10-d sample collection period. Feed ingredients and total feces and urine were collected during 4 consecutive d and rumen fluid was collected 0, 1, 2, 4, and 6 h relative to feeding. Milk yield was recorded daily and milk samples were collected on 4 consecutive milkings. Ingestion of Co, Mn, and Zn was higher for HTM compared with CON group by 216, 233, and 93%, respectively. Dry matter intake averaged 25.0 (SE = 0.6) kg/d, and apparent total-tract digestibility of major nutrients was similar between treatments. There was no measurable effect of HTM on ruminal pH, major volatile fatty acids, and protozoa counts. Isovalerate molar proportion was 9.4% greater for HTM compared with CON group. Neither milk yield (43.5 kg/d; SE = 0.8) nor milk fat and protein concentrations differed between treatments. Milk urea nitrogen concentration was significantly higher for HTM (11.7 mg/dL) compared with CON group (9.7 mg/dL; SE = 0.7). Fecal excretion of Co, Mn, and Zn increased by 223, 198, and 75%, respectively, for HTM compared with CON group. Urinary excretions of TM were marginal compared with feces, and only urinary Co and Mn were significantly higher for HTM than CON cows as similarly obtained for serum Co and Mn concentrations. Milk TM yields were not modified by treatments. In summary, short-term dietary sulfate TM supply over the recommendation did not improve cow performance but significantly increased fecal TM excretion, which could have impacts on TM accumulation in soils where manure is applied and could potentially result in leaching into nearby watersheds. Further studies are needed to evaluate the impact of high fecal TM excretion on the environment using the One Health approach. Moreover, the impacts of TM oversupply on milk production and cow health should be evaluated by long-term experiments.

Effect of nicotinic acid supplementation on digestion, metabolism, microbiome, and production in late-lactation Holstein cows.

The purpose of this experiment was to determine if nicotinic acid (NA) effects on dairy cows and rumen microbial characteristics are forage type dependent (corn silage, CS; grass silage, GS). Four late lactation (days in milk = 225 +/- 12 d) Holstein cows were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. The main effects were a CS (66.10% CS) based diet or a GS (79.59%) based diet with or without 12 g/d NA. Each experimental period lasted for 28 d. Milk production and milk components, blood metabolites, apparent total-tract nutrient digestibilities, minutes rumen pH were below 5.8 as an indicator of ruminal acidosis, and body temperature changes were analyzed as indicators of heat stress. Nicotinic acid supplementation did not improve apparent total-tract nutrient digestibility. Feeding a GS-based diet improved NDF and hemicellulose digestibility. Feeding a CS-based diet increased the apparent total-tract digestibility of fat, and minutes rumen pH below 5.8 for a greater proportion of the time. The CS-based diet also improved milk yield, milk fat and protein yields, and energy-corrected milk yield; however, somatic cell count and BHB were also increased. Supplementing NA tended to decrease nonesterified fatty acids, especially when combined with GS where DMI was low. There was a trend for the total protozoa population to increase when GS and NA were fed but decreased when CS and NA were fed. Nicotinic acid tended to decrease rumen protozoal populations of Dasytricha, but increased populations of Ophryoscolex and Diplodiniinae with GS diets and decreased with CS diets. Entodiniinae were increased with CS but NA had no effect. Body temperature was increased when a CS-based diet was fed when compared with a GS-based diet. More research is needed to determine how NA can affect rumen microbial protein synthesis and what kind of diets will provide the optimum effect.

Asparagopsis taxiformis inclusion in grass silage-based diets fed to Norwegian red dairy cows: Effects on ruminal fermentation, milk yield, and enteric methane emission

Efforts to mitigate enteric methane (CH4) emission from ruminants by using the red macroalgae Asparagopsis taxiformis (AT) have demonstrated promising results both in vitro and in vivo. We assessed the effects of wild harvested and freeze-dried AT inclusion in the grass silage-based diets of Norwegian Red dairy cows on feed intake, milk yield and composition, rumen fermentation and CH4 emission. Fifteen (9 rumen cannulated and 6 intact) multiparous cows with an average (±SD) covariate period milk yield (MY) of 33.0 (3.8) kg/day were used in the experiment. The cows were divided into three groups (n = 5) after blocking for cannulation, and initial MY. After feeding on a common diet for 21 days (i.e., Covariate period), the groups were randomly allocated to three treatments: Control (no seaweed), 0.125%AT (Control + 0.125%AT, on organic matter (OM) basis) and 0.25%AT (Control + 0.25%AT, on OM basis). The cows were adapted to their diets for 13 days, followed by 39 experimental days for data collection. Inclusion of AT at 0.125% level did not affect dry matter intake (DMI, kg/d) but signicantly reduced both MY and energy corrected milk yield (ECM, kg/d) (P < 0.05) with a tendency for lower CH4 production (g/d) relative to the control group. Dry matter intake, ECM and CH4 production were reduced (P < 0.05) by 0.25%AT inclusion relative to the Control group. Apparent total tract nutrient digestibility (%), ECM per kg DMI, CH4 yield (g CH4/kg DMI) and CH4 intensity (g CH4/kg ECM) were not affected by AT inclusion. Inclusion of AT, at both levels, significantly reduced (P < 0.05) ruminal fluid total short chain fatty acids and molar proportions of actate, while increasing (P < 0.05) the molar proportion of propionate and isovalerate. Inclusion of AT decreased contents (%) of milk fat (P = 0.018) and protein (P = 0.010) resulting in significanly lower fat and protein yields. Lactose content (%) was higher for the AT groups (P = 0.021) but this did not compensate for lower MY resulting in lower milk lactose yield. Milk iodine content increased in a dose dependent manner with AT inclusion. In conclusion, AT inclusion at 0.25% level reduced CH4 emission from dairy cows with a grass silage-based diets. However, the reduced DMI for the 0.25%AT group along with reduced MY and elevated milk iodine content for both AT groups, for this particular harvest of AT, would suggest possible constraints for large scale inclusion of AT in dairy cow production.

49 Effects of xylanase or a stimbiotic on growth performance and total tract digestibility of nutrients by pigs weaned from sows fed a lactation diet without or with xylanase

Abstract Two hypotheses were tested 1) the offspring of sows fed xylanase in lactation have greater growth performance after weaning than offspring of sows fed no xylanase, and 2) xylanase and a stimbiotic (i.e., xylanase in combination with xylo-oligosaccharides) improve growth performance, apparent total tract digestibility (ATTD) of gross energy (GE) and total dietary fiber (TDF), and digestible energy (DE) of diets for weanling pigs. A total of 120 newly weaned pigs from sows fed a lactation diet without xylanase and 120 pigs from sows fed a lactation diet containing 16,000 beechwood xylanase units (BXU) per kg of an exogenous xylanase were used [initial body weight (BW) = 5.81 ± 0.50 kg]. Pigs were allotted to a 2 × 3 factorial with two sow groups (lactation diet without or with xylanase) and three dietary treatments (i.e., control, control plus 100 g/t of xylanase, or control plus 100 g/t of stimbiotic). The xylanase (Econase XT) and the stimbiotic (Signis) were procured from AB Vista, Marlborough, UK. Pigs were weaned in 4 blocks and allotted to 12 pens per block, with 5 pigs per pen for a total of 8 replicate pens per treatment. Pigs were fed phase 1 diets from d 1 to 14, phase 2 diets from d 15 to 28, and phase 3 diets from d 29 to 42 post-weaning. Average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F) were calculated. Fecal samples were collected at the end of phases 2 and 3. Data were analyzed using the MIXED procedure of SAS. Sow group, diet, and the interaction between sow group and diet were fixed effects, and block and replicate within block were random effects. Results indicated that for the overall experiment, there were no interactions between sow group and diet, and sow lactation diet treatment did not impact any post-weaning growth or digestibility parameters in the weaned pigs (Table 1). However, weaned pigs had greater (P &amp;lt; 0.05) ADG, G:F, ATTD of GE and TDF, and DE in phase 2 if fed the diet with stimbiotic than if fed the xylanase diet or the control diet, but pigs fed the xylanase diet had greater (P &amp;lt; 0.05) ADG, G:F, ATTD of GE and TDF, and DE than pigs fed the control diet (Table 2). In phase 3, pigs fed the diet with xylanase or stimbiotic had greater (P &amp;lt; 0.05) ADG, ATTD of GE and TDF, and DE than pigs fed the control diet. In conclusion, pigs fed diets containing xylanase or stimbiotic had greater nutrient digestibility and DE, resulting in greater overall ADG, G:F, and final body weight on d 42 post-weaning, but feeding sows xylanase in lactation did not influence post-weaning growth performance.

236 The effects of replacing dried distiller’s grains with solubles with heat-treated soybean meal on nutrient intake and digestibility in forage-based diets

Abstract Cattle growth is calculated through dry matter intake, average daily gain and gain:feed measures that assume performance and digestibility are correlated. Hence, evaluating nutrient digestibility and flow provides additional explanations for subsequent growth performance. Therefore, five fistulated Jersey steers [Initial body weight (BW) = 288 ± 22 kg) fitted with ruminal, duodenal, and ileal cannulas were utilized in a 4 × 5 row-column design to determine intake and total tract nutrient digestibility when replacing dried distiller’s grains plus solubles (DDGS) with heat-treated soybean meal (TSBM) in forage-based growing diets. The 56-d study contained 4 periods, each period lasting 14 d [9 d of adaptation and 5 d of collection (d 0 to 4)]. Dietary treatments partially replaced DDGS, included at 16% diet dry matter (DM), with TSBM at increasing inclusion levels of 0 (TSBM0), 4 (TSBM4), 8 (TSBM8), and 12% (TSBM12) DM. Basal diets contained 43.5% corn silage, 36.5% oat hay, and 4% meal supplement (DM). Chromic oxide was incorporated into the diet daily at 0.25% DM as a digesta marker. Steers were housed in individual tie stalls during the 5-d collection period. Treatment diets were fed daily at 0800 h with orts being weighed at 0730 h and subsampled on d 0 to d 4 each period. Fecal collection bags were harnessed to each steer from d 0 to d 4 to collect fecal weight and subsampled twice daily (0700 and 1900 h). Digestibility and feed intake were analyzed utilizing the MIXED procedure of SAS with treatment and period as fixed effects and animal as a random effect. There were no differences (P ≥ 0.14) in DM, organic matter (OM), neutral detergent fiber (NDF), starch and nitrogen (N) intakes among treatments. Fecal DM, OM, NDF, starch, and N output resulted in no treatment effects (P ≥ 0.24). Subsequently, total tract apparent digestibility differences (P ≥ 0.32) were not detected for DM, OM, NDF, and starch content. However, N total tract apparent digestibility was significantly different (P &amp;lt; 0.03) with TSBM0 resulting in less N digestibility than TSBM12 (65.54% and 71.59%, respectively). Replacing a portion of DDGS with TSBM does not result in deleterious digestive effects in forage-based growing diets. As a result, the utilization of DDGS or TSBM as the primary protein source will depend on growth performance, feedstuff availability and economics.

172 Effects of post-MSC DDGS inclusion in gestation diets on total tract nutrient and energy digestibility compared with other fiber sources

Abstract The high fiber content of corn dried distiller grains with solubles (DDGS) make it an ideal candidate for inclusion in gestation sow diets. Gestating sows, however, have greater utilization of fibrous ingredients, and nutrient values attained in grower pigs are not representative of nutrient metrics for gestating sows. The objective of this study was to evaluate apparent total tract digestibility (ATTD) of energy and nutrients from post-protein separation (post-MSC) DDGS provided to gestating sows in comparison with soyhulls and sugar beet pulp; two commonly used fiber sources in gestation diets. Pregnant sows [n = 22; parity 0 to 1; initial body weight (BW) = 190 ± 10 kg] were allocated to 1 of 6 dietary treatments in a crossover design with two collection periods (period 1 from d 40-59 of gestation and period 2 from d 60-79 of gestation) to attain at least 7 observations per treatment. Two of the six diets were practical corn-soybean meal-based gestation diets with either soyhulls (17.5% inclusion) or post-MSC DDGS (15% inclusion) to determine ATTD of energy and nutrients in complete diets. The remaining four diets included a corn-basal diet and the basal diet plus 30% inclusion of post-MSC DDGS, soyhulls, or sugar beet pulp. Titanium dioxide was included as an indigestible marker to calculate ATTD. Sows were fed experimental diets (2.2 kg/d in a single feeding) in two 20-d collection periods where the initial 14 d considered a diet adaptation period followed by 5 d for total collection of urine (collected using urine catheters inserted on d 14) and grab fecal samples. Energy values for the post-MSC DDGS, soyhulls, and sugar beet pulp in the corn-basal diets were calculated using differential procedure. Data were analyzed with ANOVA and fixed to a mixed linear model using treatment as the main effect and collection period as a random variable. The ATTD of the post-MSC DDGS practical diet was 8% greater in ATTD of crude protein and 13% greater in ATTD of ether extract than the practical soyhull diet (P &amp;lt; 0.01). The ATTD of gross energy of post-MSC DDGS was 16% greater than soyhulls (P &amp;lt; 0.01). This resulted in an 800 and 750 kcal/kg greater digestible energy and metabolizable energy content, respectively on an as-fed basis in post-MSC DDGS compared with soyhulls and sugar beet pulp (P &amp;lt; 0.01). The post-MSC DDGS also had a net energy value (as-fed basis) 700 kcal/kg greater than soyhulls and sugar beet pulp. In conclusion, post-MSC DDGS is suitable for inclusion in gestating sow diets as a fiber source while meeting the energy needs of the gestating sow.

Particle size of insoluble fibres and gelation of soluble fibres influence digesta passage rate throughout the gastrointestinal tract of finishing pigs

Fibres, as abundant in agricultural by-products, exhibit a large range of physicochemical properties that can influence digestive processes such as digesta mean retention time (MRT), thereby affecting nutrient digestion kinetics. In this study, we investigated the effects of particle size of insoluble fibres, and gelation of soluble fibres on MRT of liquids, fine solids, and fibrous particles in the different segments of the gastrointestinal tract (GIT) of pigs. Twenty-four boars (51.6 ± 4.90 kg) were allocated to four diets; two diets contained 15% wheat straw, either coarsely chopped or finely ground (1-mm screen), two diets contained 27% wheat bran without or with the addition of 10% low-methylated pectin. After 14 days of adaptation to the diet, a total collection of faeces was performed to determine the total tract digestibility of nutrients. Thereafter, pigs were fed diets supplemented with tracers for at least 5 days and dissected following a frequent feeding procedure to approach steady-state passage of digesta. The MRT of liquids (Co-EDTA), fine solids (TiO2), and fibrous particles (Chromium-mordanted fibres) in the different segments of the GIT were quantified. In the stomach, particle size reduction of straw decreased the MRT of fine solids by 02:39 h, and fibrous particles by 07:21 h (P < 0.10). Pectin addition to the wheat bran diet reduced the MRT of fine solids by 03:09 h, and fibrous particles by 07:10 h (P < 0.10), but not of liquids, resulting in less separation between digesta phases in the stomach compared with the bran diet (P < 0.05). In the mid−small intestine (SI), pectin addition reduced the MRT of fibrous particles and the separation between fibrous particles and fine solids. No further effects of particle size reduction of straw nor pectin addition on MRT and digestibility of starch, nitrogen, or fat were observed in the SI. In the large intestine (LI), particle size reduction of straw reduced separation between fibrous particles and fine solids (P < 0.10), while pectin addition had no effects. Total tract, non-starch polysaccharide degradation of straw was poor (∼31%), and unaffected by particle size reduction (P > 0.10). The complete fermentation of pectin did not influence the degradation of wheat bran fibres (∼51%). In conclusion, the effects of particle size of insoluble fibres and gelling properties of soluble fibres on the passage of digesta phases were most pronounced in the stomach, but less prominent in distal segments of the GIT.

Effectiveness of near-infrared spectroscopy to predict the chemical composition of feces and total-tract apparent nutrients digestibility estimated with undigestible neutral detergent fiber or acid-insoluble ash in lactating buffaloes' feces

Following a comparison of nutrient total-tract digestibility estimates in lactating buffaloes using single-point undigestible NDF (uNDF) or acid-insoluble ash (AIA) as internal markers, the potential of fecal near-infrared spectroscopy (NIRS) to provide calibration equations for the assessment of the chemical composition of feces and nutrient total-tract digestibility estimated with internal markers was explored. Chemical analyses were performed on 147 fecal samples from lactating buffaloes reared on 5 farms in central Italy (Naples). Each farm fed a silage-based TMR to the buffaloes, and the TMR was sampled in the 2 d before the fecal collection. The TMR and individual fecal samples were collected and analyzed for DM, OM, ash, AIA, ether extract (EE), starch, fiber fractions (amylase-treated NDF without residual ash [aNDFom], amylase-treated NDF inclusive of residual ash [aNDF], ADF without residual ash [ADFom], ADF, hemicellulose, cellulose, ADL, uNDF), N, CP and CP bound to aNDF (NDICP) and to ADF (ADICP). The uNDF content was determined through a 240-h in vitro fermentation and employed, together with AIA as markers, to estimate the total-tract apparent digestibility and total-tract digestibility of DM, OM, ash, N, CP, EE, aNDFom, aNDF, NDIP, ADFom, and ADF, ADIN, ADL, hemicellulose, cellulose, starch, NFC, and the B3 fraction of N (NB3). No correlation was found between DM and OM digestibility estimated with AIA and uNDF as internal markers. Weak correlations were detected for all the other nutients digestibilities, and strong correlations were observed for EE, ADFom, hemicellulose, NDIN, ADIN, NB3, NFC, and starch. The sample set (n = 147) was divided in a calibration set (n = 111) and a validation set (n = 36) to "train" and "validate" the fecal NIRS curve through an external validation process. An estimation usable for preliminary or initial evaluation was obtained for N, CP, and aNDF fecal content. An excellent prediction was obtained for total tract digestibility of ADIN (R2 = 0.90) when estimated with uNDF as the internal marker. The NIRS technology was not able to accurately predict all the other traits and the estimated nutrient digestibility of lactating buffalo diets from fecal spectra.

Supplementation of feedlot lambs with magnesium oxide and sodium bicarbonate: Effects on performance, nutrient digestibility, rumen environment, serum biochemistry and antioxidant indices

The present experiment was conducted to obtain an appropriate addition strategy of magnesium oxide (MgO) for feedlot lambs and to elucidate how the combined addition of MgO and sodium bicarbonate (NaHCO3) influences the growth performance and carcass characteristics of feedlot lambs. Sixty male Dorper-Hu hybrid lambs (32.76 ± 0.85 kg) were randomly assigned to 20 pens (3 lambs per pen; 5 pens per treatment). Lambs received a corn-based total-mixed ration (TMR, 80:20 concentrate to forage) without supplementation (CON) or with the inclusion (dry matter basis) of 15 g/kg NaHCO3 (SB), 2.5 g/kg MgO + 7.5 g/kg NaHCO3 (MG1) or 5 g/kg MgO + 7.5 g/kg NaHCO3 (MG2). Buffer addition effectively increased ruminal pH and water intake in feedlot lambs (P < 0.01). The MG2 group had lower dry matter intake (P ≤ 0.03), while the MG1 group showed higher average daily gain and lower feed-to-gain ratio than the other groups (P < 0.01). Compared to the CON and SB groups, MG1 and MG2 groups had greater total tract nutrient digestibility, except for the stage 1 of DM and ADF (P < 0.01). Adding MgO with NaHCO3 improved total volatile fatty acids concentration (P < 0.01). Microbial community analysis revealed enhanced Prevotella abundance in both MG1 and MG2 groups (P = 0.04). Additionally, MG1 and MG2 groups also both exhibited greater serum antioxidant capacity compared to CON and SB groups (P ≤ 0.03). The MG1 group showed greater dressing percentage, and ribeye area than other groups (P < 0.01). Overall, the recommended supplementation strategy for the lambs' diet was 2.5 g/kg MgO + 7.5 g/kg NaHCO3. The mixture of MgO and NaHCO3 enhanced the total tract nutrient digestibility, rumen fermentation, and serum antioxidant capacity in lambs, resulting in improved lamb growth and carcass performance.

Performance and nutrient digestibility of growing pigs fed highly or low fermentable coarse or finely ground fibre-rich feedstuffs

ABSTRACT Dietary fibre is mainly classified according to its chemical characteristics but structure and particle size of fibre-rich feedstuff can also be decisive for digestion and performance. So far, only few studies investigated this in pigs. This experiment aimed to compare coarse and finely ground dried hemp plants and apple pomace regarding performance and ileal and total tract nutrient digestibility of growing pigs. Coarse or finely ground apple pomace or dried hemp plants were added to the diet of 56 nine weeks old growing pigs (DanBred x Duroc), housed in flat decks with each 2 animals. The growing pigs received the experimental diets for three weeks while performance was recorded. Eight pigs per group were sacrificed and digesta and organ tissue sampled. The stomach health was evaluated by visually scoring of the mucosa integrity. Apparent ileal (AID) and total tract digestibility (ATTD) were calculated using titanium dioxide as marker. Statistical analyses were performed using two-way ANOVA (p < 0.05). The highest feed intake (fibre particle size, p = 0.018) and bodyweight gain (fibre particle size, p = 0.018; fibre source x particle size interaction, p = 0.040), was observed in animals fed finely ground apple pomace, while the feed conversion ratio was 8–12% lower in pigs fed finely ground fibre sources (p = 0.012). No differences in stomach mucosa integrity were detected between the groups. The relative pancreas (p = 0.045), stomach (p < 0.001), and jejunum (p = 0.010) weights were higher in animals fed diets containing apple pomace. In contrast, the relative liver, caecum and colon weights were not affected by fibre source or particle size. The AID of protein and amino acids was not affected, while ATTD was increased by fibre source (hemp vs. apple pomace) reducing faecal nitrogen excretion. The AID of calcium was increased when diets contained apple pomace (p < 0.001), while zinc AID and ATTD were enhanced when diets contained dried hemp (p = 0.016; p = 0.016, respectively). Our results suggest that the structure as well as the chemical characteristics should be considered in a future fibre evaluation system in pigs.

Feeding live or inactive yeast to primiparous Jersey cows: nutrient digestibility, rumen fermentation, and milk fatty acid profile

ABSTRACT The aim of this study was to evaluate the effects of live yeast (LY) or inactive yeast (IY) on intake and apparent total-tract digestibility of nutrients, ruminal fermentation, milk yield and composition, milk fatty acid profile, N utilisation, and microbial protein synthesis of primiparous Jersey cows. Twelve primiparous Jersey cows were employed, with an average body weight of 403 kg, a lactation period of 100 days, and average daily milk output of 14.7 kg. The experimental diets were: 1 – CON (no additives); 2 – LY (inclusion of 40 g/day of live yeast); 3 – IY (inclusion of 40 g/day of inactivated yeast wall). Cows fed LY exhibited the greatest DM intake. Cows’ intake IY had the greatest digestibility of DM, OM, and NDF. Feeding IY reduced ruminal concentrations of acetate, isobutyrate, and branched-chain fatty acids. Cows fed either LY or IY increased the production of milk and FCM. Cows under the LY treatment had greater milk fat content. Cows fed LY had the greatest N intake. Yeast treatments also increased the absorbable purine estimation. Supplementing primiparous dairy cows with yeast products, especially live yeast, improved dry matter intake by positively influencing digestibility, particularly for starch and NDF.

Effects of saturated fatty acids with lysophospholipids on production and nutrient digestibility in lactating cows

The objective of the experiment was to determine the effects of supplemental saturated fatty acid (SFA) sources, lysophospholipids (LPL), and their interaction on production and nutrient digestibility in lactating dairy cows. The experiment was conducted with 48 cows in a randomized complete block design. Cows were blocked (total 12 blocks) by parity and days in milk and randomly assigned to 4 dietary treatments in each block (2 × 2 factorial arrangement), i.e., 2 sources of fat supplements, C16:0 (palmitic acid, PA)- or C18:0 (stearic acid, SA)-enriched fat, with or without LPL. The experiment was conducted for 6 wk to measure daily dry matter intake and milk yield and weekly milk composition. During the last week of the experiment, spot fecal and urine samples were collected to determine total-tract nutrient digestibility. Milk samples in the last week were also collected to analyze for milk fatty acid (FA) profile. All data were analyzed using the mixed procedure of SAS where block was used as a random effect and FA, LPL, and the interaction of FA by LPL were used as fixed effects. Week and interactions of week by FA or LPL were included for production measures. Different sources of SFA did not affect dry matter intake and milk yield. However, PA increased (39.7 vs. 36.8 kg) energy-corrected milk compared with SA due to increased milk fat yield. No effect of LPL on production measures was observed. Total-tract digestibilities of dry matter, organic matter, crude protein, and total FA were not different between PA and SA, but PA increased (41.4 vs. 38.8%) neutral detergent fiber digestibility compared with SA. Supplementation of LPL increased (64.7 vs. 60.5%) total FA digestibility, especially 18-carbon FA (74.1 vs. 68.2%). An interaction of SFA by LPL was found for 16-carbon FA digestibility. The PA diet increased the concentration of 16-carbon FA in milk fat and SA increased the concentration of preformed FA (≥18 carbons). Supplementation of LPL decreased the concentration of trans-10 C18:1. No difference in N utilization and excretion among treatments was observed. In conclusion, PA was more effective in improving milk fat yield of lactating cows compared with SA. Supplementation of LPL increased digestibility of total FA, especially 18-carbon FA but did not affect production.

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.

Effect of monensin and live-cell yeast supplementation on lactation performance, feeding behavior, and total-tract nutrient digestibility in dairy cows

Effect of monensin and live-cell yeast supplementation on lactation performance, feeding behavior, and total-tract nutrient digestibility in dairy cows

The Effects of Harvest Maturity of Eragrostis tef 'Moxie' Hay and Supplemental Energy Source on Forage Utilization in Beef Heifers.

The phenological stage of maturity of grasses and supplementation program can impact forage utilization in grazing beef cattle. However, the potential interaction between harvest maturity of Eragrostis tef (teff) hay and energy supplement source was yet to be fully evaluated. Therefore, our objective was to determine the effects of harvest maturity of teff hay and supplemental energy sources on nutrient intake, apparent total-tract nutrient digestion, nitrogen (N) utilization, and ruminal fermentation characteristics in beef heifers. A split-plot design with teff hay harvest maturity as the whole plot and supplemental energy source as the subplot was administered in a three-period (21 d), three × three Latin square design. Six crossbred beef heifers (804 ± 53.6 kg of body weight; BW) were allocated to two harvest maturities (early- (EH]) or late-heading (LH)) and to two supplemental energy sources (no supplement (CON), or rolled corn grain or beet pulp pellet fed at 0.5% of BW). Data were analyzed using SAS. There was no harvest maturity × energy supplement interaction. Although harvest maturity had no impact on total dry matter intake (DMI), crude protein (CP) intake was greater (p < 0.01) for EH than LH heifers. Total intakes of dry (DM) and organic matter (OM) were also greater (p < 0.01) for supplemented than CON heifers, whereas acid detergent fiber (ADF) intake was greater for beet pulp heifers compared to heifers fed the CON diet and supplemental corn grain. Harvest maturity had no impact on ruminal pH. However, mean ruminal pH was lower (p = 0.04), duration pH < 6.2, and molar proportions of butyrate and branched-chain fatty acids were greater (p ≤ 0.049) for heifers fed corn grain compared to CON and beet pulp diets. Heifers fed EH hay had greater (p ≤ 0.02) apparent total-tract DM, OM, CP, NDF, and ADF digestibility than heifers fed LH hay. Although there was no supplemental energy effect on microbial nitrogen (N) flow, it was greater (p < 0.01) for EH than LH heifers. Apparent N retention, which did not differ, was negative across all diets. In summary, delaying the harvest of teff hay from the EH to LH stage of maturity compromised nutrient supply, which was not attenuated by feeding supplemental corn grain and beet pulp at 0.5% of diet DM. Because N retention was negative across harvest maturity, there might be a need to provide both energy and protein supplements to improve growth performance when feeding teff hay to beef cattle.

Effects of increasing dose of a hybrid bacterial 6-phytase on apparent total tract nutrient digestibility, release of free myoinositol, and retention of calcium and phosphorus, and growth performance of pigs

The objective of this study was to investigate the effects of increasing doses of a hybrid bacterial 6-phytase on apparent total tract digestibility (ATTD) of energy and nutrients, plasma level of free myoinositol, retention of calcium (Ca) and phosphorus (P), and growth performance of growing pigs fed Ca and P deficient diets. A total of 15 barrows [21.5 ± 1.4 kg BW; Duroc × (Landrace × Yorkshire)] were allotted to a triplicated 5 × 5 Latin square design with 5 dietary treatments and 5 periods per each square. Pigs were individually housed in a metabolism crate. Five dietary treatments consisted of 5 levels of phytase (0, 500, 1000, 1500, and 2000 FTU/kg) supplemented to a basal diet containing nutrients meeting the requirement except for Ca and P. The basal diet was deficient in total Ca and P by 2.2 and 1.7 g/kg below the recommendations from NRC, respectively. Data were analyzed using orthogonal polynomial contrasts using Proc MIXED of SAS and the optimal phytase levels were determined by a broken line analysis using Proc NLMIXED. Increasing phytase supplementation increased (linear: P < 0.01; quadratic: P < 0.01) ATTD of Ca and P and retention of Ca and P. Increasing phytase supplementation increased (linear: P < 0.05; quadratic: P < 0.05) myoinositol contents in plasma. Based on broken line analyses, ATTD of Ca and retention of Ca were increased until phytase supplementation were increased from 0 to 668 ± 65 FTU/kg (P < 0.01) and 0 to 668 ± 69 FTU/kg (P < 0.01), respectively. The ATTD of P and retention of P were increased until phytase supplementation contents were increased from 0 to 780 ± 86 FTU/kg (P < 0.01) and 0 to 773 ± 93 FTU/kg (P < 0.01), respectively. Myoinositol contents in plasma were increased (11.4 to 22.8 µmol/L) until phytase supplementation were increased from 0 to 705 ± 212 FTU/kg (P < 0.05). Increasing phytase supplementation linearly increased (P < 0.05) average daily gain and tended to linearly increase (P = 0.053) gain to feed ratio. In conclusion, supplementation of a hybrid bacterial 6-phytase improved ATTD of Ca and P, retention of Ca and P, complete hydrolysis of phytate, and growth performance of pigs compared with pigs fed a Ca and P deficient basal diet. Supplementation of a hybrid bacterial 6-phytase at a range of 650 to 800 FTU/kg feeds provided the optimal improvement of Ca, P, and phytate utilization.