Neutral Detergent Fiber Degradability Research Articles

Efeito de um aditivo fúngico multiespécie no perfil de fermentação ruminal, de-gradabilidade e cinética de produção de gases

Two experiments evaluated the effect of a multispecies fungal complex (BP, BIOPREMIX MX®, Ruminal Fermentation Tech, Uruguay). In Experiment 1 (E1), the impact of adding BP to a total mixed ration (TMR) on ruminal fermentation profile and TMR in situ degradation kinetics was assessed. In Experiment 2 (E2), the effect of adding BP to various substrates on in vitro fermentability was examined. In E1, 4 Holstein cows with rumen cannulas were randomly assigned to Control (TMR with forage:concentrate ratio 75:25) or Control + 120 g/cow/d of BP (BP) and received ad libitum TMR for 30 days. Samples of TMR were ruminally incubated to estimate in situ degradation kinetic. Ruminal pH, ammonia, and volatile fatty acids (VFA) concentrations were measured just before feeding, 4 h and 8 h post feeding. In E2, a factorial arrangement included two BP levels (0 -Control or 6.5 g BP per kg dry matter incubated-WBP) and 8 substrates. In vitro gas production kinetics (GPk), dry matter digestibility (IVDMD), methanogenic potential (CH4), partitioning factor (PF), VFA, and microbial crude protein (MCP) were estimated. The BP increased proportion of propionate (P ≤ 0.05) and reduced ketogenic:glucogenic ratio and Lag phase of NDF (P ≤ 0.05). WBP tended to increase IVDMD, and substrate affected GPk, IVDMD, CH4, PF, VFA and MCP (P ≤ 0.01). Overall, BP improved ruminal metabolism favoring a more glucogenic profile, a shortening Lag phase in NDF degradation, and increasing IVDMD.

Novel oxidising feed additives reduce in vitro methane emissions using the rumen simulation technique

Enteric methane (CH4) produced by ruminant livestock is a potent greenhouse gas and represents significant energy loss for the animal. The novel application of oxidising compounds as antimethanogenic agents with future potential to be included in ruminant feeds, was assessed across two separate experiments in this study. Low concentrations of oxidising agents, namely urea hydrogen peroxide (UHP) with and without potassium iodide (KI), and magnesium peroxide (MgO2), were investigated for their effects on CH4 production, total gas production (TGP), volatile fatty acid (VFA) profiles, and nutrient disappearance in vitro using the rumen simulation technique. In both experiments, the in vitro diet consisted of 50:50 grass silage:concentrate on a dry matter basis. Treatment concentrations were based on the amount of oxygen delivered and expressed in terms of fold concentration. In Experiment 1, four treatments were tested (Control, 1× UHP + KI, 1× UHP, and 0.5× UHP + KI), and six treatments were assessed in Experiment 2 (Control, 0.5× UHP + KI, 0.5× UHP, 0.25× UHP + KI, 0.25× UHP, and 0.12× MgO2). All treatments in this study had a reducing effect on CH4 parameters. A dose-dependent reduction of TGP and CH4 parameters was observed, where treatments delivering higher levels of oxygen resulted in greater CH4 suppression. 1× UHP + KI reduced TGP by 28 % (p = 0.611), CH4% by 64 % (p = 0.075) and CH4 mmol/g digestible organic matter by 71 % (p = 0.037). 0.12× MgO2 reduced CH4 volume by 25 % (p > 0.05) without affecting any other parameters. Acetate-to-propionate ratios were reduced by treatments in both experiments (p < 0.01). Molar proportions of acetate and butyrate were reduced, while propionate and valerate were increased in UHP treatments. High concentrations of UHP affected the degradation of neutral detergent fibre in the forage substrate. Future in vitro work should investigate alternative slow-release oxygen sources aimed at prolonging CH4 suppression.

107 Bacterial direct-fed microbial mixtures effects on beef cattle ruminal degradability kinetics

Abstract The effects of bacterial direct-fed microbial (DFM) mixtures on beef cattle ruminal degradability were evaluated. Six ruminally cannulated beef steers (BW = 520 ± 30 kg) were used in a replicated 3 × 3 Latin square design and offered a steam-flaked corn-based finishing diet to ad libitum intake during three, 28-d periods. Treatments were: 1) Control (no DFM, lactose carrier only); 2) Treat-A (L. animalis, P. freudenreichii; B. subtilis; and B. licheniformis), at 1:1:1:3 ratio, respectively; totaling 6 × 109 CFU (50 mg)/animal-daily minimum; and 3) Treat-B, the same DFM combination, but with doses at 1:1:3:1 ratio. Bacterial counts were approximately 30% greater than the minimum expected. Pre-dehydrated (55ºC for 72 h) diets and forage substrates were ground (2 mm) and placed into 10 × 20 cm (28 µm) nylon bags (8 and 5 g, as-is respectively). The diet-substrate included a mixture of (DM basis) steam-flaked corn (70%), alfalfa hay (10%), and wet corn gluten feed (20%). The forage-substrate was represented by ‘WW-B Dahl’ Old World bluestem (Bothriochloa bladhii). Substrate in-situ bags were placed within a nylon mesh (with weights) at the ruminal ventral sac, and reversely removed at 0, 2, 4, 8, 12, 20, 32, 48, 64, 72, and 96 h after feeding. Samples were removed, rinsed, and dehydrated for 72 h at 55oC. Residues were composited within period, steer, incubation-time, corrected for residual moisture and were used to fit a first-order kinetics model using the NLIN procedure of SAS (animal = experimental unit). Steers offered Treat-A tended to show an increase on the rate of degradation of NDF (P = 0.15) and ADF (P = 0.10) fractions; increased (P &amp;lt; 0.01) hemicellulose potentially degradable fraction (B); and increased (P = 0.02) the effective degradable fraction of NDF (tendency for ADF, P = 0.08) at pre-established rate of passages of 4, 5, and 6% of the diet-substrate compared with Control, while tending to have a reduced rate of degradation for the overall DM (P = 0.06) and OM (P = 0.08) fractions. When the in-situ bags containing the forage-substrate were incubated, steers offered Treat-A showed an increased (P &amp;lt; 0.01) lag time (T0) for hemicellulose compared with Control, while those offered Treat-B had a decreased (P = 0.02) hemicellulose potentially degradable fraction (B) compared with Control. The effective degradable fraction for hemicellulose at pre-established rate of passages of 4, 5, and 6% tended (P = 0.09) to numerically increase for steers offered Treat-A compared with Control. The combination of bacteria in Treat-A enhanced the ruminal degradation of high-quality fiber components, as indicated by the improvements observed within the more degradable fractions from ingredients used in the diet and the forage substrates. Further assessment is warranted to investigate post-ruminal nutrient disappearance.

&lt;i&gt;In situ&lt;/i&gt; and &lt;i&gt;in vitro&lt;/i&gt; degradation parameters of elephant grass silage with sugarcane bagasse

The objective of this study was to evaluate the chemical composition and in situ degradability of elephant grass silage dry matter with increasing levels of sugarcane bagasse. A completely randomized design was adopted with five treatments: 0, 5, 10, 15, and 20% inclusion of sugarcane bagasse on an as-fed matter basis, with five replications, totalling 25 experimental units. The increasing proportion of sugarcane bagasse analysed was favourable only in increasing the concentration of dry matter and fibre of silages and in maintaining a considerable crude protein content. In the in situ degradation assay, the addition of sugarcane bagasse in silage decreased the ruminal degradability of dry matter, and as the passage rates increased, the effective degradability decreased. In the in vitro gas production assay, the total production of gases was decreased with the inclusion of sugarcane bagasse, as did the degradability of organic matter and neutral detergent fibre. The recommendation for the inclusion of sugarcane bagasse should be analysed according to the desired objective, emphasizing that values higher than 5% can greatly compromise the final nutritive value of elephant grass silage

Replacing soybean meal with microalgae biomass in diets with contrasting carbohydrate profile can reduce in vitro methane production and improve short-chain fatty acids production

The objective of this study was to evaluate the interaction of dietary carbohydrate profile and soybean meal (SBM) replacement with either Chlorella pyrenoidosa (CHL) or Spirulina platensis (SPI) on in vitro fermentation. This experiment was conducted as a randomized complete block design, with fermentation run (3 runs) considered as blocks. The treatments were arranged in a 2 × 5 factorial design, where the first factor was the carbohydrate profile, which was composed of diets containing 42.5% NDF and 26.8% starch (HF-LS) or 26.8% NDF and 40.6% starch (LF-HS) and the second factor was the protein source, in which a control diet (100% SBM), partial replacement of SBM with CHL (1/2 CHL) or SPI (1/2 SPI), or total replacement of SBM with CHL or SPI were used. All experimental diets were formulated to have 17% crude protein. The ruminal fluid was collected from 2 lactating Holstein cows, buffered with Van Soest medium at a ratio of 1:2 and added to serum bottles containing 0.50 g of the experimental diets. Bottles were incubated at 39°C for 24 and 48 h in triplicate; headspace pressure was measured, along with gas collection for methane (CH4) quantification at 0, 2, 4, 8, 16, 24, 36, and 48 h after incubation. The final medium was used to measure pH, ammonia, and volatile-fatty acid (VFA). After incubation, feed bags were recovered and used for estimation of degradability of DMD, NDF, and OMD. Statistical analysis was carried out using the MIXED procedure of SAS, with carbohydrate profile, protein source, assay, and its interactions as fixed effects, with run and bottle as random effects. Orthogonal contrasts were used to compare carbohydrate profile, algae species, carbohydrate profile × algae interaction, and linear and quadratic effects of SBM replacement with CHL or SPI. There was no interaction effect between carbohydrate profile and algae source. LF-HS improved gas production, degradability of nutrients, and VFA, mainly increasing the production of butyrate and propionate. When compared with CHL, SPI had a greater degradability of nutrients and branched VFA, along with reduction in total gas production and tended to reduce total CH4 yield. The replacement of SBM with algae linearly reduced the degradability of nutrients, along with a linear reduction in gas production. When replacement of SBM with only SPI was evaluated, SPI slightly reduced the degradability of nutrients; however, it promoted a linear reduction in CH4 yield, as well as reduction in CH4 yield by unit of degraded DM, NDF, and OM. In summary, there was no interaction of carbohydrate profile and protein source, which means that SBM replacement had a similar effect, regardless of dietary carbohydrate profile. Spirulina may be a more suitable algae source when compared with Chlorella due to the potential to reduce CH4.

Effect of additive cellulase on fermentation quality of whole-plant corn silage ensiling by a Bacillus inoculant and dynamic microbial community analysis.

Whole-plant corn silage (WPCS) has been widely used as the main roughage for ruminant, which promoted the utilization of corn stover for animal feed production. However, rigid cell wall structure of corn stover limits the fiber digestion and nutrients adsorption of WPCS. This study investigated the effect of adding cellulase on improving the fermentation quality of WPCS ensiling with a Bacillus complex inoculant. With the Bacillus (BA), the lactic acid accumulation in the WPCS was significantly higher than that in control (CK). The additive cellulase (BC) increased the lactic acid content to the highest of 8.2% DW at 60 days, which was significantly higher than that in the CK and BA groups, and it reduced the neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents from 42.5 to 31.7% DW and 28.4 to 20.3% DW, respectively, which were significantly lower than that in the CK and BA groups. The crude protein and starch were not obviously lost. Dynamic microbial community analysis showed that the Bacillus inoculant promoted the lactic acid bacteria (LAB) fermentation, because higher abundance of Lactobacillus as the dominant bacteria was observed in BA group. Although the addition of cellulase slowed the Lactobacillus fermentation, it increased the bacterial community, where potential lignocellulolytic microorganisms and more functional enzymes were observed, thus leading to the significant degradation of NDF and ADF. The results revealed the mechanism behind the degradation of NDF and ADF in corn stover, and also suggested the potential of cellulase for improving the nutritional quality of WPCS.

Effects of dietary forage neutral detergent fiber and rumen degradable starch ratios on chewing activity, ruminal fermentation, ruminal microbes and nutrient digestibility of Hu sheep fed a pelleted total mixed ration.

Pelleted total mixed ration (P-TMR) feeding, which has become a common practice in providing nutrition for fattening sheep, requires careful consideration of the balance between forage neutral detergent fiber (FNDF) and rumen degradable starch (RDS) to maintain proper rumen functions. The present study aimed to investigate the effects of the dietary FNDF/RDS ratio (FRR) on chewing activity, ruminal fermentation, ruminal microbes, and nutrient digestibility in Hu sheep fed a P-TMR diet. This study utilized eight ruminally cannulated male Hu sheep, following a 4 × 4 Latin square design with 31 d each period. Diets consisted of four FRR levels: 1.0 (high FNDF/RDS ratio, HFRR), 0.8 (middle high FNDF/RDS ratio, MHFRR), 0.6 (middle low FNDF/RDS ratio, MLFRR), and 0.4 (low FNDF/RDS ratio, LFRR). Reducing the dietary FRR levels resulted in a linear decrease in ruminal minimum pH and mean pH, while linearly increasing the duration and area of pH below 5.8 and 5.6, as well as the acidosis index. Sheep in the HFRR and MHFRR groups did not experience subacute ruminal acidosis (SARA), whereas sheep in another two groups did. The concentration of total volatile fatty acid and the molar ratios of propionate and valerate, as well as the concentrate of lactate in the rumen linearly increased with reducing dietary FRR, while the molar ratio of acetate and acetate to propionate ratio linearly decreased. The degradability of NDF and ADF for alfalfa hay has a quadratic response with reducing the dietary FRR. The apparent digestibility of dry matter, organic matter, neutral detergent fiber, and acid detergent fiber linearly decreased when the dietary FRR was reduced. In addition, reducing the dietary FRR caused a linear decrease in OTUs, Chao1, and Ace index of ruminal microflora. Reducing FRR in the diet increased the percentage of reads assigned as Firmicutes, but it decreased the percentage of reads assigned as Bacteroidetes in the rumen. At genus level, the percentage of reads assigned as Prevotella, Ruminococcus, Succinivibrio, and Butyrivibrio linearly decreased when the dietary FRR was reduced. The results of this study demonstrate that the dietary FRR of 0.8 is crucial in preventing the onset of SARA and promotes an enhanced richness of ruminal microbes and also improves fiber digestibility, which is a recommended dietary FRR reference when formulating P-TMR diets for sheep.

Effects of bacterial direct-fed microbial mixtures offered to beef cattle consuming finishing diets on intake, nutrient digestibility, feeding behavior, and ruminal kinetics/fermentation profile.

Effects of bacterial direct-fed microbial (DFM) mixtures on intake, nutrient digestibility, feeding behavior, ruminal fermentation profile, and ruminal degradation kinetics of beef steers were evaluated. Crossbred Angus ruminally cannulated steers (n = 6; body weight [BW] = 520 ± 30kg) were used in a duplicated 3 × 3 Latin square design and offered a steam-flaked corn-based finisher diet to ad libitum intake for 3, 28-d periods. Treatments were 1) Control (no DFM, lactose carrier only); 2) Treat-A (Lactobacillus animalis, Propionibacterium freudenreichii, Bacillus subtilis, and Bacillus licheniformis), at 1:1:1:3 ratio, respectively; totaling 6 × 109 CFU (50mg)/animal-daily minimum; and 3) Treat-B, the same DFM combination, but doses at 1:1:3:1 ratio. Bacterial counts were ~30% greater than the minimum expected. Data were analyzed using the GLIMMIX procedure of SAS with the model including the fixed effect of treatment and the random effects of square, period, and animal (square). For repeated measure variables, the fixed effects of treatment, time, and their interaction, and the random effects of square, period, animal (square), and animal (treatment) were used. Preplanned contrasts comparing Control × Treat-A or Treat-B were performed. Intake and major feeding behavior variables were not affected (P ≥ 0.17) by treatments. Steers offered Treat-A had an increased (P = 0.04) ADF digestibility compared with Control. Steers offered Treat-A experienced daily 300min less (P = 0.04) time under ruminal pH 5.6, a greater (P = 0.04) ruminal pH average and NH3-N concentration (P = 0.05) and tended (P = 0.06) to have a lower ruminal temperature compared to Control. Ruminal VFA was not affected (P ≥ 0.38) by treatments. Steers offered Treat-A increased (P = 0.02) and tended (P = 0.08) to increase the ruminal effective degradable NDF and ADF fractions of the diet-substrate, respectively. When the forage-substrate (low quality) was incubated, steers offered Treat-A tended (P = 0.09) to increase the effective degradable hemicellulose fraction compared to Control. In this experiment, the bacterial combinations did not affect intake and feeding behavior, while the combination with a greater proportion of B. licheniformis (Treat-A) elicited an improved core-fiber digestibility and a healthier ruminal pH pattern, in which the ruminal environment showed to be more prone to induce the effective degradability of fiber fractions, while also releasing more NH3-N.

Ruminal degradation characteristics of bagasse with different fermentation treatments in the rumen of beef cattle.

This experiment aimed to study the degradation characteristics of bagasse after three fermentation treatments in beef cattle. Bagasse 1 was treated with 0.3% lactic acid bacteria (w/w). Bagasse 2 was treated with 0.3% mixed strains (Saccharomyces cerevisiae, Aspergillus niger, Aspergillus oryzae, and lactic acid bacteria at 2:1:1:1). Bagasse 3 was treated with 0.1% cellulase and 0.1% xylanase in addition to 0.3% mixed strains of bagasse 2. The dry matter (DM), crude ash (ASH), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) in the bagasses were determined. Compared to the control bagasse (without the strain and enzyme treatments), three fermented bagasses showed higher DM after 4h fermentation. The CP and ASH contents in fermented bagasse 3 were the highest, while the contents of NDF and ADF in fermented bagasse 3 were the lowest among all the groups. The effective degradability of DM, CP, NDF, and ADF was highest in fermented bagasse 3 among the evaluated bagasse feed, followed by fermented bagasse 2 > fermented bagasse 1 > bagasse. Overall, fermented bagasse 3 was better than the control and other treated bagasses, thus fermented bagasse 3 is a hopeful source for ruminant diet of beef cattle.

Fennel seeds dietary inclusion as a sustainable approach to reduce methane production and improve nutrient utilization and ruminal fermentation.

Ruminants are considered a major producer of methane (CH4 ). Therefore, the present study aimed to determine the ability of dry fennel seeds to affect in vitro gas production and fermentation. Fennel seeds were included at 0% (Control), 0.5%, 1%, 1.5%, and 2% DM of a diet containing per kg DM: 500 g concentrate feed mixture, 400 g berseem hay, and 100 g of rice straw. The incubations lasted 48 h. Fennel seeds increased (P< 0.001) the asymptotic gas production and decreased its rate, while decreasing the production and proportion of CH4 (P< 0.05) and increased its rate. Moreover, fennel seed increased DM and neutral detergent fiber (P< 0.01) degradability, and increased total production of short-chain fatty acids, acetate, and propionate (P< 0.05). Compared to the control, fennel seeds increased (P< 0.01) metabolizable energy, partitioning factor, and microbial crude protein production. Overall, fennel seeds can be included up to 2% DM in ruminant diets as an environmentally friendly product in animal farming due to its ability to improve feed utilization, ruminal fermentation and while reducing CH4 production.

Essential Oil Blends with or without Fumaric Acid Influenced In Vitro Rumen Fermentation, Greenhouse Gas Emission, and Volatile Fatty Acids Production of a Total Mixed Ration

The growing interest in improving rumen fermentation and mitigating methane emissions necessitates the use of essential oil blends (EOB) and fumaric acid (FA). This study evaluated the synergistic effect of four EOB with or without FA supplementation on in vitro dry matter digestibility, greenhouse gas emission, and total volatile fatty acid production using inoculum from three rumen-cannulated Black Angus beef cows. The study was arranged in a 4 × 2 + 1 factorial design to evaluate the effects of the four EOB and two FA levels on a total mixed ration (TMR). The EOB dosage was 100 µL while FA was added at 3% of total mixed ration. The EOB × FA interaction (p &lt; 0.05) influenced the dry matter, neutral detergent fiber, and hemicellulose degradabilities. All the EOB and FA (EFA) treatments decreased (p &lt; 0.001) the dry matter degradability compared to the control (TMR substrate only). The EFA4 treatment reduced the neutral detergent fiber and hemicellulose degradabilities compared to the control. The ruminal pH was influenced (p &lt; 0.001) by both the EOB and FA inclusion, and the EOB × FA interaction was significant. The microbial mass was higher (p &lt; 0.001) in the EFA1, EFA4, and EOB4 compared to the control and the EOB3 treatments. The EFA1 and EOB1 produced less (p &lt; 0.001) gas than the control by 29.1 and 32.1%, respectively. Compared with the control, the EFA1 and EOB1 treatments decreased (p &lt; 0.001) methane gas by 90.8% and 86.4%, respectively, while the carbon dioxide was reduced (p = 0.004) by 65.7 and 57.9%, respectively. The EOB × FA interaction was significant (p &lt; 0.001) for the total and individual volatile fatty acid concentrations. The inclusion of FA increased the propionate concentration by 9.5% and decreased (p = 0.02) the acetate concentration by 4%. In summary, the synergistic effect of the EOB and FA offers an effective way to reduce greenhouse gas emission and enhance total volatile fatty acids.

Influence of different growing stages of whole-plant soybeans on their nutrient content and silage quality for cattle

ABSTRACT The objective of this study was to determine the effects of growing stage (GS) on morphological and chemical composition of whole-plant soybean (WPS), and fermentative profile and chemical composition of whole-plant soybean silage (SS). This study was divided into two trials conducted in a complete randomised block design. The first trial evaluated the effect of GS from R1 to R8 (59–135 d after sowing) on morphological and chemical composition of WPS and its botanical components. The second trial determined the effects of GS from R3 (71 d after sowing) to R7 (124 d after sowing) on dry matter (DM) losses, fermentative profile, chemical composition and aerobic stability of SS. The proportion of leaves in WPS was reduced, while stem and pod proportions were increased as the GS progressed. Ensiling WPS at R6 and R7 decreased the contents of acetic acid, lactic acid and branched-chain fatty acids, and ethanol, and increased the contents of propionic acid and NH3-N. However, silage butyric acid concentrations in R6 and R7 were relatively high (18.1 and 19.9 g/kg DM, respectively). Butyric acid and buffering capacity varied according to GS with the lowest values observed in silages derived from GS R3, R5 and R7, and the highest values observed in silages made from GS R5. Later GS resulted in greater contents of DM, crude protein and ether extract, and lower contents of acid detergent fibre and non-fibre carbohydrate in SS. The high fat of SS produced from later GS limits high inclusion levels in ruminant diets. Morphological components impacted chemical composition of SS, whereas the R7 stage improved fermentative profile and resulted in an SS with greater in situ degradability of DM and neutral detergent fibre.

Chemical, Physical, and Degradation Characteristics of Ryegrass Cultivars Grown in Autumn and Winter for Dairy Cows.

During winter and early spring, pasture supply is usually lower than the demand in New Zealand dairy farming systems and thus the 'autumn saved pastures' (stockpiling) are introduced to fill the gap. This study aimed to investigate the chemical, physical, and degradation characteristics of ryegrass pastures, the predominant forage in New Zealand, grown in autumn and winter. To serve as 'autumn saved pasture', nine ryegrass cultivars, comprising three types (three perennial, three hybrid, and three Italian), were grown in late autumn (Autumn) and early winter (Winter) and harvested after 7 and 9 weeks of regrowth, respectively. The experiment had two experimental factors: ryegrass type (or cultivar) and harvest season. These experimental factors were in a randomised block design with the forage plot as the experimental unit. The degradation characteristics were assessed in the rumen of fistulated cows using the in situ incubation technique. Perennial ryegrass had a greater neutral detergent fibre (NDF) concentration (468 g/kg dry matter (DM)) than the hybrid (435 g/kg DM) or Italian (414 g/kg DM) ryegrasses. Italian ryegrasses had the greatest soluble fraction of DM (64.2% vs. 46.7% and 40.7%) and the greatest degradation rate of an insoluble but degradable fraction of DM (0.221 vs. 0.189 and 0.145/h) than the hybrid and perennial ryegrasses. Compared with the Winter ryegrass, the Autumn ryegrass had a greater crude protein concentration (246 vs. 208 g/kg DM) and a greater NDF concentration (486 vs. 392 g/kg DM) but a lower calculated soluble carbohydrate concentration (152 vs. 263 g/kg DM). It is concluded that there are notable variations among the cultivars, highlighting distinctions in parameters, such as NDF concentration, soluble fractions, degradation rates, and nutrient content among the perennial, hybrid, and Italian ryegrasses, as well as the seasonal variations observed between autumn and winter growth. These findings will not only facilitate enhanced nutrition for dairy cows as they undergo the transition phase but also have practical implications for future research and dairy cow nutrition.

Effect of exogenous fibrolytic enzymes cocktail incorporation on in vitro degradation and fermentation characteristics of oats straw based total mixed ration

The study was conducted to evaluate the effects of increasing doses: 0 (control), 0.20, 0.40, 0.60, 0.80 and 1.00 % DM of an exogenous fibrolytic enzymes (EFE) cocktail preparation on in vitro gas production (GP), nutrient degradability and fermentation characteristics of oats straw based Total Mixed Ration (TMR) with 60:40 roughage to concentrate ratio using sheep rumen liquor. The chemical composition of all the feed ingredients used for preparation of the experimental TMR (containing 16.63% crude protein and 90.51% organic matter) were within the normal ranges. Increasing the incorporation level of enzyme cocktail linearly as well as quadratically increased net GP, metabolisable energy content, short chain fatty acid concentrations and microbial crude protein production up to 0.60% DM level (L3) with no additional improvement at further higher levels. There were significant improvements in degradability of dry matter, organic matter and neutral detergent fibre up to the enzyme dose of 0.60% DM (L3) with constant values thereafter. Fermentation characteristics response to varying incorporation doses of EFE cocktail also revealed improvements up to 0.60% DM level (L3) with no effect on non-protein nitrogen contents. It is recommended that EFE cocktail incorporation dose of 0.60% DM to be used for efficient utilisation of oats straw based complete feed; however, this requires further testing by in vivo studies.

Effects of cashew nut shell extract and monensin on in vitro ruminal fermentation, methane production, and ruminal bacterial community

The objective of this study was to evaluate the effects of cashew nut shell extract (CNSE) and monensin on ruminal in vitro fermentation, CH4 production, and ruminal bacterial community structure. Treatments were as follows: control (CON, basal diet without additives); 2.5 μM monensin (MON); 0.1 mg CNSE granule/g DM (CNSE100); and 0.2 mg CNSE granule/g DM (CNSE200). Each treatment was incubated with 52 mL of buffered ruminal content and 500 mg of total mixed ration for 24 h using serum vials. The experiment was performed as a complete randomized block design with 3 runs. Run was used as a blocking factor. Each treatment had 5 replicates, in which 2 were used to determine nutrient degradability, and 3 were used to determine pH, NH3-N, volatile fatty acids, lactate, total gas, CH4 production, and bacterial community composition. Treatment responses for all data, excluding bacterial abundance, were analyzed with the GLIMMIX procedure of SAS v9.4. Treatment responses for bacterial community structure were analyzed with a PERMANOVA test run with the R package vegan. Orthogonal contrasts were used to test the effects of (1) additive inclusion (ADD: CON vs. MON, CNSE100, and CNSE200); (2) additive type (MCN: MON vs. CNSE100 and CNSE200); and (3) CNSE dose (DOS: CNSE100 vs. CNSE200). We observed that pH, acetate, and acetate:propionate ratio in the CNSE100 treatment were lower compared with CNSE200, and propionate in the CNSE100 treatment was greater compared with CNSE200. Compared with MON, CNSE treatments tended to decrease total lactate concentration. Total gas production of CON was greater by 2.63% compared with all treatments, and total CH4 production was reduced by 10.64% in both CNSE treatments compared with MON. Also, compared with MON, in vitro dry matter degradabilities in CNSE treatments were lower. No effects were observed for NH3-N or in vitro neutral detergent fiber degradability. Finally, the relative abundances of Prevotella, Treponema, and Schwartzia were lower, whereas the relative abundances of Butyrivibrio and Succinivibrio were greater in all treatments compared with CON. Overall, the inclusion of CNSE decreased CH4 production compared with MON, making CNSE a possible CH4 mitigation additive in dairy cattle diets.

Ability of three dairy feed evaluation systems to predict postruminal outflows of nitrogenous compounds in dairy cows: A meta-analysis

Adequate prediction of postruminal outflow of protein fractions is the starting point for the determination of metabolizable protein supply in dairy cows. The objective of this meta-analysis was to compare the performance of 3 dairy feed evaluation systems (National Research Council [NRC], Cornell Net Protein and Carbohydrate System [CNCPS], and National Academies of Sciences, Engineering and Medicine [NASEM]) to predict outflows (g/d) of nonammonia nitrogren (NAN), microbial N (MiN), and nonammonia nonmicrobial N (NANMN). Predictions of rumen degradabilities (% of nutrient) of protein (RDP), NDF, and starch were also evaluated. The data set included 1,294 treatment means from 312 digesta flow studies. The 3 feed evaluation systems were compared using the concordance correlation coefficient (CCC), the ratio of root mean square prediction error (RMSPE) on standard deviation of observed values (RSR), and the slope between observed and predicted values. Mean and linear biases were deemed biologically relevant and are discussed if higher than a threshold of 5% of the mean of observed values. The comparisons were done on observed values adjusted or not for the study effect; the adjustment had a small effect on the mean bias but the linear bias reflected a response to a dietary change rather than absolute predictions. For the absolute predictions of NAN and MiN, CNCPS had the best-fit statistics (8% greater CCC; 6% lower RMSPE) without any bias; NRC and NASEM underpredicted NAN and MiN, and NASEM had an additional linear bias indicating that the underprediction of MiN increased at increased predictions. For NANMN, fit statistics were similar among the 3 feed evaluation systems with no mean bias; however, the linear bias with NRC and CNCPS indicated underprediction at low predictions and overprediction at elevated predictions. On average, the CCC were smaller and RSR ratios were greater for MiN versus NAN indicating increased prediction errors for MiN. For NAN responses to a dietary change, CNCPS also had the best predictions, although the mean bias with NASEM was not biologically relevant and the 3 feed evaluation systems did not present a linear bias. However, CNCPS, but not the 2 other feed evaluation systems, presented a linear bias for MiN, with responses being overpredicted at increased predictions. For NANMN, responses were overpredicted at increased predictions for the 3 feed evaluation systems, but to a lesser extent with NASEM. The site of sampling had an effect on the mean bias of MiN and NANMN in the 3 feed evaluation systems. The mean bias of MiN was higher in omasal than duodenal studies in the 3 feed evaluation systems (from 55 to 61 g/d) and this mean bias was twice as large when 15N labeling was used as a microbial marker compared with purines. Such a difference was not observed for duodenal studies. The reasons underlying these systematic differences are not clear as the type of measurements used in the current meta-analysis does not allow to delineate if one site or one microbial marker is yielding the "true" postruminal N outflows. Rumen degradabilities of protein was underpredicted with CNCPS, and RDP responses to a dietary change was underpredicted by the 3 feed evaluation systems with increased RDP predictions. Rumen degradability of NDF was underpredicted and had poor fit statistics for NASEM compared with CNCPS. Fit statistics were similar between CNCPS and NASEM for rumen degradability of starch, but with an underprediction of the response with NASEM and absolute values being overpredicted with CNCPS. Multivariate regression analyses showed that diet characteristics were correlated with prediction errors of N outflows in each feed evaluation system. Globally, compared with NAN and NANMN, residuals of MiN were correlated with several moderators in the 3 feed evaluation systems reflecting the complexity to measure and model this outflow. In addition, residuals of NANMN were correlated positively with RDP suggesting an overestimation of this parameter. In conclusion, although progress is still to be made to improve equations predicting postruminal N outflows, the current feed evaluation systems provide sufficient precision and accuracy to predict postruminal outflows of N fractions.

Effects of Different Cutting Stages and Additives on the Fermentation Quality and Microbial Community of Sudangrass (Sorghum sudanense Stapf.) Silages

(1) Background: Previous studies have indicated that ferulic acid esterase (FAE), cellulase and xylanase have synergistic effects in lignocellulose degradation, and the cutting stage has a major impact on silages. Whether these additives affect the silages at different cutting stages is unclear. (2) Methods: Sudangrass height at the tested cutting stages was 1.8 m (S1) and 2.0 m (S2). The silage from the two cutting stages was treated with FAE-producing Lactobacillus plantarum (LP), cellulase and xylanase (CX) and a combination of LP and CX (LP+CX) for 30 and 60 days. (3) Results: Compared with CK, adding LP+CX significantly decreased the pH and the content of neutral detergent fiber (NDF) and acidic detergent fiber (ADF) (p &lt; 0.05) and increased the lactic acid (LA) concentration (p &lt; 0.05), dry matter (DM) content and crude protein content. Adding LP+CX effectively degraded lignocellulose in sudangrass, and the NDF and ADF degradation rates at the two stages were all more than 30%. In comparison, cutting at the S2 stage led to a lower pH and higher LA and DM contents (p &lt; 0.05). Additives and the cutting stage exerted a strong effect on the silage microbial community, and Firmicutes and Lactiplantibacillus became the most dominant bacterial phyla and genera, especially at the S2 stage. (4) Conclusions: The results suggest that FAE-producing L. plantarum, cellulase and xylanase had synergistic effects on sudangrass silages, especially at the S2 stage, and their use can thus serve as an efficient method for ensiling.

Evaluation of a new commercial source of monensin in lactating dairy cows and continuous culture fermenters

The objective of this experiment was to evaluate a new commercial source of monensin (MON) on performance of mid-lactation dairy cows and fermentation parameters of dual-flow continuous culture fermenters. In Experiment 1, 43 Holstein cows (25 multiparous and 18 primiparous; 175 ± 97 DIM; 45.3 ± 10 kg/d milk yield; 692 ± 68 kg BW; mean ± SD) were used in a randomized block design experiment with a 15-d covariate and a 9-wk treatment period. The first 3 wk of the treatment period were considered adaptation and the last 6 wk were used for data collection and analysis. Treatments were: Control (CTR; no MON added), Rumensin® 90 (RUM; 350 mg/d MON from Elanco Animal Health Inc.), and Monovet® 90 (MVet; 350 mg/d MON from Huvepharma® Inc. US). All cows were fed the same base diet throughout the experiment and treatments were top-dressed during the treatment period. Orthogonal contrasts were used to evaluate CTR vs. MON (RUM + MVet) and RUM vs. MVet. Compared with CTR, MON tended to increase milk yield (43.8 vs. 42.3 kg/d) but did not affect DMI or feed efficiency. The MVet treatment improved feed efficiency compared with RUM (1.70 vs. 1.58). Treatments did not affect milk fat content and yield, milk protein yield, MUN concentration, or energy-corrected milk yield. In Experiment 2, nine continuous culture fermenters were used in a randomized block design experiment with two 10-d periods. Fermenters were fed once a day approximately 100 g DM of the same diet fed in Experiment 1. Treatments were: CTR, RUM (2 mg/L MON from Rumensin® 90), and MVet (2 mg/L MON from Monovet® 90). Monensin did not affect DM, OM, NDF, ADF, and CP degradability or total VFA production (mmol/d), but decreased acetate, butyrate, and isobutyrate molar proportions and increased propionate molar proportion compared with CTR. Both sources of MON decreased acetate to propionate ratio compared with CTR (1.61 vs. 2.40). Adding MON increased daily production of propionate (74.1 vs. 108 mmol/d) and decreased that of butyrate and isobutyrate compared with CTR. Monensin supplementation decreased ammonia-N production (433 vs. 545 mg/d) compared with CTR. Overall, results indicate MON tended to increase milk yield and altered VFA profile in the rumen and in vitro, and that MVet is a suitable source of MON for dairy cows.

Supplementing branched-chain volatile fatty acids in dual-flow cultures varying in dietary forage and corn oil concentrations. I: Digestibility, microbial protein, and prokaryotic community structure

Branched-chain amino acids are deaminated by amylolytic bacteria to branched-chain volatile fatty acids (BCVFA), which are growth factors for cellulolytic bacteria. Our objective was to determine the dietary conditions that would increase the uptake of BCVFA by rumen bacteria. We hypothesized that increased forage would increase cellulolytic bacterial abundance and incorporation of BCVFA into their structure. Supplemental polyunsaturated fatty acids, supplied via corn oil (CO), should inhibit cellulolytic bacteria growth, but we hypothesized that additional BCVFA would alleviate that inhibition. Further, supplemental BCVFA should increase neutral detergent fiber degradation and efficiency of bacterial protein synthesis more with the high forage and low polyunsaturated fatty acid dietary combination. The study was an incomplete block design with 8 dual-flow continuous cultures used in 4 periods with 8 treatments (n = 4 per treatment) arranged as a 2 × 2 × 2 factorial. The factors were: high forage (HF) or low forage (LF; 67 or 33%), without or with supplemental CO (3% dry matter), and without or with 2.15 mmol/d (which included 5 mg/d of 13C each of BCVFA isovalerate, isobutyrate, and 2-methylbutyrate). The isonitrogenous diets consisted of 33:67 alfalfa:orchardgrass pellet, and was replaced with a concentrate pellet that mainly consisted of ground corn, soybean meal, and soybean hulls for the LF diet. The main effect of supplementing BCVFA increased neutral detergent fiber (NDF) degradability by 7.6%, and CO increased NDF degradability only in LF diets. Supplemental BCVFA increased bacterial N by 1.5 g/kg organic matter truly degraded (6.6%) and 0.05 g/g truly degraded N (6.5%). The relative sequence abundance decreased with LF for Fibrobacter succinogenes, Ruminococcus flavefaciens, and genus Butyrivibrio compared with HF. Recovery of the total 13C dose in bacterial pellets decreased from 144 µg/ mg with HF to 98.9 µg/ mg with LF. Although isotope recovery in bacteria was greater with HF, BCVFA supplementation increased NDF degradability and efficiency of microbial protein synthesis under all dietary conditions. Therefore, supplemental BCVFA has potential to improve feed efficiency in dairy cows even with dietary conditions that might otherwise inhibit cellulolytic bacteria.

Effect of Anaerobic Calcium Oxide Alkalization on the Carbohydrate Molecular Structures, Chemical Profiles, and Ruminal Degradability of Rape Straw.

To improve the utilization efficiency of rape straw, anaerobic calcium oxide (CaO) alkalization was conducted, and advanced molecular spectroscopy was applied, to detect the internal molecular structural changes. Rape straw was treated with different combinations of CaO (3%, 5%, and 7%) and moisture levels (50% and 60%) and stored under anaerobic conditions. We investigated the carbohydrate chemical constituents, the ruminal neutral detergent fiber (aNDF) and acid detergent fiber (ADF) degradation kinetics, and the carbohydrate molecular structural features. CaO-treated groups were higher (p < 0.05) for ash, Ca, non-fiber carbohydrate, soluble fiber, and the ruminal degradability of aNDF and ADF. In contrast, they were lower (p < 0.05) for the contents of aNDF, ADF, and indigestible fiber. With CaO levels rising from 3% to 7%, the content of aNDF and ADF linearly decreased (p < 0.05). CaO treatment and anaerobic storage changed the molecular characteristics, including structural parameters related to total carbohydrates (TC), cellulosic compounds (CEC), and structural carbohydrates (STC). Alterations in cellulosic compounds' spectral regions were highly correlated with the differences in carbohydrate chemical constituents and the ruminal digestibility of rape straw. In summary, CaO treatment and anaerobic storage altered the molecular structural parameters of carbohydrates, leading to an enhancement in the effective degradability (ED) of aNDF and ADF in rape straw. From the perspective of processing cost and effectiveness, 5% CaO + 60% moisture could be suggested as a recommended treatment combination.