Effects Of Exogenous Fibrolytic Enzymes Research Articles

The effects of exogenous fibrolytic enzymes on the in vitro release of xylooligosaccharides and monosaccharides varies across six varieties of wheat

Wheat is a widely used cereal grain for pig and poultry feeds globally. Despite this, there are noticeable differences in its nutritive value, potentially due to varying characteristics like inherent non-starch polysaccharide (NSP) content and composition. Fibrolytic enzymes help degrade NSP and thereby improve feed efficiency in livestock. However, it has been suggested that these enzymes have different effects dependent upon the characteristics of the wheat variety used in a feed. This study investigated the efficacy of different enzyme-wheat variety combinations, by quantifying the release of NSP-derived xylooligosaccharides (XOS) and monosaccharides from six varieties of wheat (Maris Huntsman, Highbury, Paragon, Sinuelo, Chinese Spring and Pavon 76) over a 24 h in vitro incubation with commercially available fibrolytic enzymes (Econase XT, Econase MP1000 or Barley P700). Complete non-starch acid hydrolysis showed there were differences between varieties in their total monosaccharide contents (P < 0.001). There were significant wheat variety x enzyme x incubation time interactions for the release of xylobiose, galactose and glucose (all P < 0.001) and significant enzyme x wheat variety interactions for the release of xylotriose (P = 0.022), xylose (P < 0.001) and arabinose (P = 0.028). Clear differences in release of XOS were observed between the different combinations of enzyme and wheat variety. Econase XT increased xylotriose release from Highbury wheat, and xylobiose release from Sinuelo, with both wheat varieties showing comparable release of xylose. These findings suggest that the fibrolytic enzymes tested have some specificity for the wheat varieties. Hence it might be possible to optimise the combinations of wheat variety and enzyme used in animal feeds, to help maximise the feed efficiency of livestock.

The effects of exogenous fibrolytic enzymes on the in vitro generation of xylooligosaccharides and monosaccharides is dependent upon cereal type

Fibrolytic enzymes are routinely added to non-ruminant livestock feeds to help degrade the non-starch polysaccharide (NSP) contents and thereby improve feed efficiency. This study investigated the range of xylooligosaccharides (XOS) and monosaccharides produced from four cereal samples (barley, maize, oats and wheat) over a 72 h in vitro incubation using 3 commercially available (AB Vista, Marlborough, Wiltshire, United Kingdom) fibrolytic enzymes, Econase XT, Econase MP1000 and Barley P700, all containing endo-xylanase with other combinations of enzymes. Complete non-starch acid hydrolysis showed there were differences between cereals in the total monosaccharide (P < 0.01). There was a cereal x enzyme x incubation time 3-way interaction in the generation of XOS (xylotetraose, xylotriose and xylobiose) (P < 0.01) indicating the generation of XOS varies dependent on both the cereal and the enzyme used. The enzymes failed to generate any detectable xylose from maize. For xylose there was also a cereal x enzyme x incubation time 3-way interaction (P < 0.05). Econase XT generated the greatest quantity of xylose, with 38% of available xylose from wheat being released after 72 h, 11% from barley and 9% from oats, whilst no xylose was detected from maize using any of the 3 commercial enzyme preparations. For arabinose and galactose production there was a cereal x enzyme x incubation time 3-way interaction (P < 0.01), whilst glucose release was only significantly affected by cereal (P < 0.05) or time (P < 0.05). These findings suggest that the fibrolytic enzymes tested have some specificity for certain cereals and therefore it might be possible to optimise the combinations used in animal feeds, to help maximise the feed efficiency of livestock.

PSVI-4 Effects of exogenous fibrolytic enzymes on beef cattle fed growing diets: Ruminal microbiome

Abstract The effect of pre-treatment with fibrolytic enzymes [cellulase/xylanase (Trichoderma ressie)] of growing diets (high quality and low-quality) on ruminal microbiome relative abundance (RA) were evaluated. Ruminally cannulated beef steers (n = 5; BW = 520 ± 30 kg) were used in a 5×4 unbalanced Latin square design using a 2×2 factorial arrangement of treatments: (a) growing diet quality [high (HQ) and low (LQ)] and (b) enzyme inclusion (0 or 0.75 mL/kg of diet DM). Steers were individually fed ad libitum throughout four 21-d periods consisting of 14-d of adaptation and 7-d of collections. Ruminal fluid samples (100 mL) were collected on d-5 of each collection-period, at 6 h post feeding for DNA extraction and determination of microbial RA. Microbiome data were sequenced by Illumnia® NovaSeq™ 6000 (16S rRNA). Regardless of enzyme×diet quality interaction (P ≥ 0.11) or pre-treatment with enzyme (P ≥ 0.12), Domain RA was affected (P ≤ 0.04), in which LQ diets increased RA of Bacteria (93.25 vs. 86.80%) and decreased Archaea (6.75 vs. 13.20%). In Phylum, LQ diets decreased RA (P ≤ 0.04) of Euryarchaeota (6.75 vs. 13.21%), and increased Bacteroidetes (11.22 vs. 2.26%). Within Class, LQ diets decreased RA (P ≤ 0.04) of Clostridia (38.66 vs. 51.40%), Methanobacteria (6.75 vs. 13.21%), and increased Bacteroidia (10.62 and 1.47%). Within Order LQ diets, decreased RA (P ≤ 0.04) of Clostridiales (38.47 vs. 51.29%), Methanobacteriales (6.75 vs. 13.21%), and increased Bacteroidales (10.62 vs. 1.47%). In Family, LQ diets showed decreased RA (P ≤ 0.04) of Methanobacteriaceae (6.75 vs. 13.21%), Ruminococcaceae (6.71 vs. 2.18%), and increased Prevotellaceae (9.83 vs. 1.17%). In Genus, LQ diets showed increased RA (P ≤ 0.03) of Prevotella (9.61 vs. 1.10%). The dietary pre-treatment with fibrolytic enzymes seems to not dramatically affect RA of ruminal microbiome, while growing diet quality greatly influenced ruminal microbiome RA.

PSVII-1 Effects of exogenous fibrolytic enzymes on the release of xylo-oligosaccharides from six varieties of wheat in-vitro

Abstract The study objective was to investigate the effects of in-vitro fibrolytic enzyme incubation on xylooligosaccharide (XOS) release from different wheat varieties. Six varieties of wheat were ground to a 300µm powder and subjected to total non-cellulosic hydrolysis with Trifluroacetic acid (TFA) and in-vitro incubations with one of three commercially available enzymes at their recommended doses: Econase XT (xylanase 160,000 BXU/g), Econase MP1000 (Mannase 100,000 MNU/g) or Econase BP700 (ß-glucanase 700,000 BU/g) or no added enzymes. Each wheat variety was suspended (at 5mg/ml) in 50mM sodium citrate buffer (pH 5.2) with or without the individual enzymes (n = 3), and incubated at 40.7°C in a shaking incubator. Samples were taken at 0 and 6hr. Concentrations of xylose, xylobiose and xylotriose were determined by High-Performance Anion-Exchange Chromatography coupled with Pulsed Electrochemical Detection fitted with a CarboPac PA20 (xylose) or CarboPac PA200 Column (Dionex, Thermo Scientific) and known xylose and XOS standards (Megazyme, Ltd). Data were analysed by one or two-way ANOVA (Genstat 19th Edition), with significance accepted at P &amp;lt; 0.05. After TFA hydrolysis, there were significant differences between varieties (P &amp;lt; .001, ANOVA) in total xylose contents (Huntsman &amp;gt; Paragon &amp;gt; Chinese spring &amp;gt; Sinuelo &amp;gt; Highbury = Pavon 74). In the in-vitro incubations, there was a significant effect of enzyme, but not wheat variety, on both xylose (P = 0.009) and xylotriose (P &amp;lt; .001) release at 6 hours, with Econase XT releasing more than the other two enzymes. There was a significant enzyme x wheat variety interaction (P &amp;lt; .001) for xylobiose release at 6 hours, with Econase MP1000 releasing the most from Huntsman. In conclusion, the 6 wheat varieties differed in their non-cellulosic xylose contents and there were clear differences in the amounts of XOS released by the 3 enzymes. Further trials are needed to investigate whether the in-vitro experiments are indicative of results observed in-vivo.

Effects of exogenous fibrolytic enzymes on the ruminal fermentation of agro-industrial by-products

This research was performed to evaluate the effects of increasing doses of exogenous fibrolytic enzymes (EFE), namely at 0 (control), 1 (low), 2 (medium) and 4 (high) μL/g dry matter (DM), on the ruminal fermentation of low-quality agro-industrial by-products, grape pomace, almond hull and pomegranate peel. For pomegranate peel, the addition of EFE increased gas production linearly from the immediately soluble fraction, and from the insoluble fraction, the potential of gas production (significant linear effect), organic matter digestibility and metabolizable energy. The highest doses were the most effective. As the doses increased, the effectiveness increased accordingly. Unlike pomegranate peel, EFE had a quadratic effect on the indices of almond hull, namely a significant response on gas production from the immediately soluble fraction, the insoluble fraction, potential of gas production, organic matter digestibility and metabolizable energy. The lowest dose was the most effective while the highest dose had inhibitory effects for gas indices, organic matter digestibility and metabolizable energy. On the other hand, this supplementation had no effect on the ruminal fermentation of grape pomace. This study indicates that the response to this feed additive was influenced by the dose, the structure of the substrate, and the interaction between dose and the substrate. Exogenous fibrolytic enzymes could enhance the use of almond hull and pomegranate peel in ruminant nutrition, and reduce their negative environmental impact. Keywords: almond hull, feed additive, grape pomace, pomegranate peel

Effect of exogenous fibrolytic enzymes in total mixed ration on milk yield, composition, feed efficiency in Holstein Friesian crossbred cows

An experiment was conducted to evaluate the effect of exogenous fibrolytic enzymes (EFE; 800 IU/g endo 1,4- β glucanase, 700 IU/g 1 (3),4-β glucanase and 2700 IU/g endo 1,4-β xylanase) @ 240 mg/kg total mixed ration (TMR) feeding on milk and components yield as well as feed utilization efficiency in Holstein Friesian [HF] crossbred cows. Twenty early lactating HF crossbred cows having uniform 4% fat corrected milk (FCM) yield and body weight were used to access the effect on nutrients intake, milk yield, milk composition, feed conversion efficiency and cost of feeding. The crossbred cows fed EFE supplemented TMR produced more milk, 4% FCM and milk fat. The supplementation of EFE resulted in higher milk solid not fat (SNF), protein and lactose as well as higher milk fat and total solids (TS). The consumption of nutrients/kg 4% FCM were less in EFE group cow, whereas only numerical improvement in nutrients intake/kg milk was noticed. The gross protein and energy efficiencies were significantly improved on EFE supplementation. The return over feed cost was 15.87% higher for cows fed EFE supplemented TMR compared to control TMR. In conclusion, feeding of EFE produced significantly higher 4% FCM and milk fat with improved feed conversion efficiency and better economic returns in HF crossbred cows.

Serum Lipid Profile in Sheep Fed Diet Incorporated with Feed Additives

feeding trial to study the supplementation effect of exogenous fibrolytic enzymes (EFE) cocktail and wormwood herb on serum lipid profile was conducted for 90 days in twenty crossbred lambs that were divided into four equal groups viz. T0 (Control) and T1, T2 and T3 (treatment groups). T0 received total mixed diet (TMR) without any supplementation, while in treatments groups TMR was supplemented either with EFE cocktail alone @ 0.60% (T1) or wormwood herb alone @ 4.50% (T2) and in a combination of the two feed additives (T3). At the end of the feeding trial, 6 days of digestibility trial was carried out to assess the supplementation effect in vivo on nutritional parameters and serum total lipids and different lipoprotein fractions were carried out at the start (0 d) and subsequently at monthly intervals of the experiment (30, 60 and 90 d). Nutrient digestibility, content as well intake were significantly higher in groups fed diets supplemented with the feed additives either alone (p less than 0.05) or in-combination (p less than 0.01). No significant effect was observed on the total cholesterol level at any point of evaluation, and on total triglycerides level-up to 30 d, but significant reduction was noted in T2 at 60 (p less than 0.05) and 90 (p less than 0.01) days as compared to T1. Significant (p less than 0.01) effect on HDL level was evident as elevated in T2 while reduced in T1 at day 60 and 90. In contrast, LDL values were reduced in T2 and elevated in T1 group at day 30 (p less than 0.05), 60 and 90 (p less than 0.01). VLDL levels did not change among the groups up to 30 d, whereas reduced at day 60 (p less than 0.05) and 90 (p less than 0.01) in T2 as compared to T1. Lowest (p less than 0.01) AI value was observed in the T2 group at day 90 compared to other groups. It was concluded that dietary incorporation of wormwood herb as a feed additive for sheep improved nutritional status along with health beneficial effects when supplemented alone.

Effect of exogenous fibrolytic enzymes and ammonia fiber expansion on the fermentation of wheat straw in an artificial rumen system (RUSITEC)1.

This study investigated the effect of treatment of wheat straw using ammonia fiber expansion (AFEX) and exogenous fibrolytic enzymes (Viscozyme) on fiber digestibility, rumen fermentation, microbial protein synthesis, and microbial populations in an artificial rumen system [Rumen Simulation Technique (RUSITEC)]. Four treatments were assigned to 16 vessels (4 per treatment) in 2 RUSITEC apparatuses in a randomized block design. Treatments were arranged as a 2 × 2 factorial using untreated or AFEX-treated wheat straw with or without exogenous fibrolytic enzymes [0 or 500 μg of protein/g straw dry matter (DM)]. Fibrolytic enzymes were applied to straw, prior to sealing in nylon bags. The concentrate mixture was provided in a separate bag within each fermentation vessel. The RUSITECs were adapted for 8 d and disappearance of DM, neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein (CP) was measured after 48 h of incubation. Ammonia fiber expansion increased (P < 0.01) the disappearance of wheat straw DM (69.6 vs. 38.3%), NDF (65.6 vs. 36.8%), ADF (61.4 vs. 36.0%), and CP (68.3 vs. 24.0%). Total dietary DM, organic matter (OM), and NDF disappearance was also increased (P ≤ 0.05) by enzymes. Total microbial protein production was greater (P < 0.01) for AFEX-treated (72.9 mg/d) than untreated straw (63.1 mg/d). Total gas and methane (CH4) production (P < 0.01) were also greater for AFEX-treated wheat straw than untreated straw, with a tendency for total gas to increase (P = 0.06) with enzymes. Ammonia fiber expansion increased (P < 0.01) total volatile fatty acid (VFA) production and the molar proportion of propionate, while it decreased (P < 0.01) acetate and the acetate-to-propionate ratio. The AFEX-treated straw had lower relative quantities of fungi, methanogens, and Fibrobacter succinogenes (P < 0.01) and fewer protozoa (P < 0.01) compared to untreated straw. The pH of fermenters fed AFEX-treated straw was lower (P < 0.01) than those fed untreated straw. Both AFEX (P < 0.01) and enzymes (P = 0.02) decreased xylanase activity. There was an enzyme × straw interaction (P = 0.02) for endoglucanase activity. Enzymes increased endoglucanase activity of AFEX-treated wheat straw, but had no effect on untreated straw. The addition of enzymes lowered the relative abundance of Ruminococcus flavefaciens, but increased F. succinogenes. These results indicate that AFEX increased the ruminal disappearance of wheat straw and improved fermentation and microbial protein synthesis in the RUSITEC.

Digestibility of Nutrients as Influenced by Supplementation of Exogenous Fibrolytic Enzymes in Dry Non-pregnant Cows

The study was planned to evaluate the effect of exogenous fibrolytic enzymes (EFE) supplementation for 56 days @ 240 mg/kg total mixed ration (TMR) on digestibility of dry matter and nutrients in dairy cows. Six dry non-pregnant cows were assigned in each treatment with and without EFE. The digestibility trial of seven days was conducted after 49 days of feeding. Dry matter and nutrients intake of cows was not influenced by EFE. The supplementation of EFE had improved digestibility of dry matter, organic matter, crude fiber, neutral detergent fiber, cellulose (p less than 0.01), as well as digestibility of nitrogen-free extract and acid detergent fiber, was also higher (pless than 0.05). The body weight gain of cows was higher on the supplementation of EFE in TMR. The study concluded that feeding exogenous fibrolytic enzymes (240 mg/kg) supplemented TMR improved digestibility of dry matter and nutrients, which was reflected as higher body weight gain in dry non-pregnant Gir and crossbred dairy cows.

65 Effect of exogenous fibrolytic enzymes on untreated or ammonia fiber expansion (AFEX) - treated wheat straw on in vitro semi-continuous culture fermentation using the rumen simulation technique (RUSITEC).

65 Effect of exogenous fibrolytic enzymes on untreated or ammonia fiber expansion (AFEX) - treated wheat straw on in vitro semi-continuous culture fermentation using the rumen simulation technique (RUSITEC).

67 Effects of exogenous fibrolytic enzymes on beef cattle fed growing diets: metabolism study.

67 Effects of exogenous fibrolytic enzymes on beef cattle fed growing diets: metabolism study.

Effects of exogenous fibrolytic enzyme supplementation to diets with different NFC/NDF ratios on the growth performance, nutrient digestibility and ruminal fermentation in Chinese domesticated black goats

This study was conducted to evaluate the effects of exogenous fibrolytic enzymes (EFE) supplementation into diets with different non-fiber carbohydrates (NFC)/neutral detergent fiber (NDF) ratios on growth performance, nutrient digestibility, ruminal fermentation, and microbiome in Chinese domesticated Lezhi black goats. Treatments were 2 × 2 factorial arrangement of diets using low vs. high NFC/NDF ratios (1.06 or 1.66) and with or without EFE supplementation (0 or 0.4 g cellulase and xylanase/kg dry matter of diet). Sixty four Lezhi black goats (11 ± 0.8 kg of live weight) were randomly assigned to the four treatments. High NFC/NDF ratio and EFE supplementation achieved greater average daily gain and improve feed conversion ratio (P < .05). The same treatments also significantly increased digestibility of organic matter (OM), acid detergent fiber (ADF) and NDF. In addition, the high NFC/NDF ratio diet, but not the EFE supplement, improved digestibility of crude protein (CP) and reduced ruminal pH (P < .001). Both high NFC/NDF ratio and EFE supplement decreased ruminal NH3-N concentrations significantly (P < .001), and increased the production of rumen total volatile fatty acids (VFA, P < .001), especially the molar proportion of propionate (P < .05). They reduced the molar proportion of acetate and thus the ratio of acetate to propionate (A: P) (P < .05). Both the high NFC/NDF ratio and the EFE supplement elevated the levels of microbial crude proteins (P < .01). Importantly, the combination of high NFC/NDF ratio and the EFE supplement diet raised the content of the microbial crude proteins to the highest levels among the 4 different treatment groups (P = .012). However, the high NFC/NDF ratio and the EFE supplementation had different impacts on fiber degrading activities. The high NFC/NDF ratio diet decreased, while EFE supplementation increased, the activities of cellulase and xylanase (P < .05). Among the three cellulytic bacteria detected (Ruminococcus albus, Ruminococcus flavefaciens, Fibrobacter succinogenes), only the abundance of Fibrobacter succinogenes was significantly decreased with the high NFC/NDF ratio (P = .004). These results illustrate that the diet with a high NFC/NDF ratio and EFE supplementation can improve ADG, feed conversion ratio and nutrient utilization in Lezhi black goats. These improvements are likely attributed to the elevated production of microbial crude proteins and a shift in the molar proportions of VFA in the rumen, rather than increase of cellulolytic bacteria in the rumen microbiota.

Effect of exogenous fibrolytic enzymes on performance and blood profile in early and mid-lactation Holstein cows.

The supplementation of exogenous fibrolytic enzymes (EFE) to dairy cows diets could be a strategy to improve fiber degradation in the rumen which is especially important for the early lactating cows characterized by a high milk energy output and an insufficient energy intake. The objective of this study was to examine the effects of a fibrolytic enzyme product (Roxazyme G2 Liquid, 3.8 and 3.9 mL/kg total mixed ration [TMR] DM) supplemented to a TMR on production performance and blood parameters of dairy cows during early (trial 1) and mid-lactation (trail 2). In addition, rumination activity was measured in trial 2. The nutrient digestibility of the experimental TMR was obtained by using wethers. In the digestibility trial, EFE was supplemented at a rate of 4.4 mL/kg Roxazyme G2 Liquid TMR-DM. The TMR contained 60% forage and 40% concentrate (DM basis). Twenty eight 50 ± 16 days in milk (DIM) and twenty six 136 ± 26 DIM Holstein cows were used in two 8-wk completely randomized trails, stratified by parity and milk yield level. One milliliter of the enzyme product contained primarily cellulase and xylanase activities (8,000 units endo-1,4-ß glucanase, 18,000 units endo-1,3(4)-ß glucanase and 26,000 units 1,4-ß xylanase). No differences in digestibility of DM, OM, CP, NDF and ADF were observed (P > 0.05) between the control and the EFE supplemented TMR. Addition of EFE to the TMR fed to early (trial 1) and mid-lactation cows (trial 2) did not affect daily dry matter intake (DMI), milk yield, 4% fat-corrected milk, energy-corrected milk (ECM), concentration of milk fat, protein, fat-protein-quotients, somatic cell score, energy balance, and gross feed efficiency of early and mid-lactation cows (P > 0.05). Mid-lactation cows (trial 2) fed with TMR enzyme showed a tendency of a slightly higher ECM yield (P = 0.09). The tested blood parameters were not affected by treatment in trials 1 and 2 (P > 0.05). Exogenous fibrolytic enzymes supplementation did not alter daily time spent ruminating in trial 2 (P = 0.44). In conclusion, under the conditions of this study, no positive effects of enzyme supplementation on dairy performance and health status of dairy cows during early and mid-lactation were observed.

Effect of adding cofactors to exogenous fibrolytic enzymes on preingestive hydrolysis, in vitro digestibility, and fermentation of bermudagrass haylage

Our objectives were to examine if adding metal ion cofactors (COF) to exogenous fibrolytic enzymes (EFE) would increase the beneficial effects of the EFE on the preingestive hydrolysis and in vitro digestibility and fermentation of bermudagrass haylage. In experiment 1, 5 COF (Mn2+, Co2+, Fe2+, Ca2+, and Mg2+) were screened to select the best candidates for synergistically enhancing release of water-soluble carbohydrates (WSC) from bermudagrass haylage by 5 EFE. The 5 EFE (1A, 2A, 11C, 13D, and 15D) were sourced from Trichoderma reesei and Aspergillus oryzae and they were the most effective of 12 EFE at increasing the neutral detergent fiber digestibility of bermudagrass haylage in a previous trial. Adding 1mM of each of the COF to EFE 2A or 11C synergistically increased release of WSC from bermudagrass haylage, as did adding (1mM) Fe2+ to 1A, Mn2+, Co2+, or Fe2+ to 13D, or Co2+or Fe2+ to 15D. The greatest release of WSC responses were obtained by adding Mn2+ to 11C (38%) or by adding Fe2+ to 2A or 13D (10 and 21.9%, respectively). In experiment 2, the effect of increasing the COF dose on in vitro digestibility and fermentation of bermudagrass haylage was examined using the best EFE-COF combinations from experiment 1. Effects of adding increasing doses of these COF on EFE-mediated changes in vitro digestibility depended on the COF-EFE combination. Adding 10mM Mn2+ alone to bermudagrass haylage increased DMD and NDFD by 2.7 and 6.3% and adding 11C alone increased these measures by 6.6 and 15.5%, respectively. However, adding 10mM Mn2+ with 11C resulted in 3.5 and 8.1% increases in DMD and NDFD, respectively, beyond the increases caused by adding 11C alone. Adding Fe2+ to 2A had no effects on EFE-mediated digestibility responses, but 2A prevented adverse effects of adding Fe2+ alone on DMD and NDFD. In contrast, adding Fe2+ to 13D reduced the increases in DMD and NDFD caused by adding the EFE alone. This study shows that adding COF to EFE can synergistically increase, decrease, or not affect the hydrolytic effects of EFE on bermudagrass haylage cell walls. The outcome depends on the specific EFE-COF combination and the COF dose. More research is required to understand the mechanisms resulting in these outcomes to exploit beneficial effects of COF on EFE.

The effect of exogenous fibrolytic enzymes and a ferulic acid esterase-producing inoculant on the fibre degradability, chemical composition and conservation characteristics of alfalfa silage

The objective of this study was to determine the effect of applying fibrolytic enzymes at ensiling, either alone or in combination with a ferulic acid esterase-producing bacterial silage inoculant, on the silage conservation characteristics and nutritive value of alfalfa (Medicago sativa L.). Second-cut alfalfa (340gDM/kg fresh crop) was harvested, wilted, chopped and sub-sampled into 24 batches. Samples were randomly allocated in triplicate to one of four enzyme product treatments supplying endoglucanases and xylanases: none (control), EN1, EN2, EN3; applied alone or in combination with a ferulic acid esterase-producing silage inoculant (FAEI). Treatments were arranged in a 4×2 factorial design. All enzyme treatments were applied at 2ml enzyme product/kg herbage DM, and inoculant was applied at 1×105cfu/g fresh herbage. Samples were packed into laboratory-scale silos and stored for 7, 27 or 70 days, and analysed for dry matter (DM) losses, aerobic stability, chemical composition and in vitro ruminal degradability. The use of enzymes did not affect (P>0.05) ensilage DM losses or lactic or acetic acid concentrations after 70 days of ensilage, compared to the control silage. Silage produced using EN1 had lesser neutral detergent fibre (aNDF, P=0.046) and acid detergent fibre (ADF; P=0.006) concentrations than control silage. However, no difference (P>0.05) was observed between the control silage and silage produced with EN1 for aNDF or ADF degradability (NDFD, ADFD). Silages produced with FAEI had greater DM losses (P=0.017) and pH (P<0.001) and lesser NDFD (P=0.019), ADFD (P=0.010) and proportion of lactic acid in the total fermentation products (P=0.006) after 70 days of ensilage, compared to uninoculated silages. The use of fibrolytic enzymes did not have a major effect on the ensilage fermentation of alfalfa, either ensiled alone or with an inoculant. No advantage in ruminal DM or fibre degradability was observed for silages produced with fibrolytic enzymes. The use of a ferulic acid esterase-producing inoculant alone did not improve the nutritive value of alfalfa silage, and did not promote any incremental effects when applied in combination with fibrolytic enzyme products.

Exogenous fibrolytic enzymes to unlock nutrients: Histological investigation of its effects on fibre degradation in ruminants

There is a need for a better understanding of the mode-of-action of exogenous fibrolytic enzymes (EFE) used as additives in ruminant feeds. Four forages, treated with EFE, were evaluated in vitro and histologically, in an attempt to determine the effect of EFE on tissue degradation. Weeping love grass, kikuyu leaf material, lucerne and wheat straw stem material were histologically evaluated. Simultaneously, milled samples were incubated in the rumen fluid inoculated media for the determination of in vitro digestibility. The main focus, however, was a quantitative assessment of the degradation of the plant tissue at histological level over a 24 h incubation period. Degradation of cell wall components were quantified using the image analysis software. After 12 h of incubation, cell walls of the metaxylem of kikuyu and weeping love grass leaf material were thinner for the EFE treatment than for the control treatment. Treatment also resulted in a significant thinning effect of the cell walls of kikuyu phloem (12 h) and the adaxial epidermis (24 h). The abaxial epidermis at 12 h was thinner for weeping love grass due to EFE treatment. For stem material, a thinning of the epidermis of EFE treated lucerne was observed. Histological findings were concomitant with higher in vitro digestibilities of EFE treated lucerne and kikuyu. It was concluded that image analysis can be useful to quantify changes in cell wall due to the treatment of forages with EFE. There was a definite, subtle thinning effect of EFE on cell wall thickness of plant material which could be indicative of the mode-of-action of EFE.

Effect of Exogenous Fibrolytic Enzyme Application on the Microbial Attachment and Digestion of Barley Straw In vitro.

The effects of exogenous fibrolytic enzymes (EFE; a mixture of two preparations from Trichoderma spp., with predominant xylanase and β-glucanase activities, respectively) on colonization and digestion of ground barley straw and alfalfa hay by Fibrobacter succinogenes S85 and Ruminococcus flavefaciens FD1 were studied in vitro. The two levels (28 and 280 μg/ml) of EFE tested and both bacteria were effective at digesting NDF of hay and straw. With both substrates, more NDF hydrolysis (p<0.01) was achieved with EFE alone at 280 than at 28 μg/ml. A synergistic effect (p<0.01) of F. succinogenes S85 and EFE on straw digestion was observed at 28 but not 280 μg/ml of EFE. Strain R. flavefaciens FD1 digested more (p<0.01) hay and straw with higher EFE than with lower or no EFE, but the effect was additive rather than synergistic. Included in the incubation medium, EFE showed potential to improve fibre digestion by cellulolytic ruminal bacteria. In a second batch culture experiment using mixed rumen microbes, DM disappearance (DMD), gas production and incorporation of 15N into particle-associated microbial N (15N-PAMN) were higher (p<0.001) with ammoniated (5% w/w; AS) than with native (S) ground barley straw. Application of EFE to the straws increased (p<0.001) DMD and gas production at 4 and 12 h, but not at 48 h of the incubation. EFE applied onto S increased (p<0.01) 15N-PAMN at 4 h only, but EFE on AS increased (p<0.001) 15N-PAMN at all time points. Prehydrolysis increased (p<0.01) DMD from both S and AS at 4 and 12 h, but reduced (p<0.01) 15N-PAMN in the early stage (4 h) of the incubation, as compared to non-prehydrolyzed samples. Application of EFE to barley straw increased rumen bacterial colonization of the substrate, but excessive hydrolytic action of EFE prior to incubation decreased it.

Effects of Fibrolytic Enzymes on Ruminal Fermentation and Digestibility in Steers Fed Diets with Sodium Bicarbonate

Montañez-Valdez, O.D., Pinos-Rodríguez, J.M., Martínez-Tinajero, J.J., Rojo-Rubio, R., Salinas-Chavira, J. and Avellaneda-Cevallos, J.H. 2010. Effects of fibrolytic enzymes on ruminal fermentation and digestibility in steers fed diets with Sodium bicarbonate. J. Appl. Anim. Res., 38: 191–196. The objective of this study was to evaluate the effect of exogenous fibrolytic enzymes (ENZ) on ruminal fermentation and disappearance in steers fed high-concentrate diets with sodium bicarbonate (SB, 3% of total diet). Six ruminally cannulated steers (450±15 kg) were randomly assigned to a replicate 3×3 Latin square. Experimental high-concentrate diets (70% concentrate DM) were as follow: control; ENZ (0.3% enzymes) and ENZ+BS (0.3% enzymes plus 3% SB). Dry matter intake, ruminal pH, ammonia N, ruminal disappearance of dry matter and neutral detergent fiber of diets were not affected by ENZ or ENZ+SB. Steers fed ENZ and ENZ+SB spent more time ruminating and resting and less time eating than steers on control diet. Ruminal pH and ammonia N concentrations in steers fed ENZ+BS were greater than in steers fed ENZ or not supplemented. There were scarce effects of fibrolytic enzymes on Ruminal disappearance and fermentation of high-concentrate diet with sodium bicarbonate for steers.

Effects of exogenous fibrolytic enzymes on intake, duodenal flow, and digestion in steers fed diets with whole or cracked Pima cottonseed

This study evaluated the effects of exogenous fibrolytic enzymes on intake, ruminal fermentation, and duodenal flow and digestion of nutrients in steers fed diets with whole Pima cottonseed (WPC) or cracked Pima cottonseed (CPC). Four Holstein steers (167±5 kg body weight) fitted with ruminal and duodenal cannulas with a 4×4 Latin square in a 2×2 factorial arrangement of treatments (WPC or CPC; 0 or 15 g enzyme) were used. Steers were fed wheat flaked-based diets with 9.95% of WPC or CPC as dry matter basis. Enzymes increased molar proportion of acetate in steer fed WPC, but in those fed CPC acetate decreased. Feeding enzymes increased duodenal flow of organic matter in steers fed WPC, but not in those fed CPC. Also, enzymes increased duodenal flow of N, non-ammonia N, and intestinal digestion of N in steers fed WPC and CPC.

Effect of exogenous fibrolytic enzymes on ruminal fermentation and nutrient digestion in dairy cows

The aim of the present study was to examine the effects of an exogenous fibrolytic enzyme product applied to a total mixed ration (TMR) prior to feeding on ruminal fermentation, microbial protein synthesis, nutrient digestion, and milk yield and composition. Six multiparous lactating Holstein cows (598 ± 29 kg initial live weight and 98 ± 30 days in milk) fitted with rumen and duodenal cannulae were allocated to two treatments in a crossover design over three consecutive 28-d periods. The TMR containing 50% concentrates, 30% corn silage and 20% grass silage on dry matter (DM) basis, was mixed once daily and fed twice a day. Treatments were TMR alone (Control) or TMR with an enzyme product containing primarily cellulase and xylanase activities (9000 U endo-1,4-β glucanase, 24000 U endo-1,3(4)-β glucanase and 40000 U 1,4-β xylanase per ml). The enzyme product was applied at a rate of 6.2 ml/kg TMR (DM basis). It was diluted at a rate of 1: 5 with water and applied daily to the TMR. During the control period the cows received a TMR supplemented with 36 ml water/kg TMR on DM basis. Duodenal digesta flow was measured using Cr2O3 as flow marker and microbial protein in the duodenal digesta was estimated by near-infrared spectroscopy (NIRS). There were no significant differences in ruminal pH-values, NH3-N concentrations, total SCFA concentrations and molar proportions of SCFA. No treatment effects on microbial N flow to the duodenum and efficiency of microbial protein synthesis were observed. The apparent ruminal digestibilities of DM, organic matter, NDF and ADF, milk yield and composition were also not affected by the enzyme supplementation. In this study the application of exogenous fibrolytic enzymes fed to dairy cows did not show a significant effect on any parameter tested.