In vitro evaluation of the application of an optimized xylanase cocktail for improved monogastric feed digestibility

Xylanases from glycoside hydrolase (GH) families 10 and 11 are common feed additives for broiler chicken diets due to their catalytic activity on the nonstarch polysaccharide xylan. This study investigated the potential of an optimized binary GH10 and GH11 xylanase cocktail to mitigate the antinutritional effects of xylan on the digestibility of locally sourced chicken feed. Immunofluorescence visualization of the activity of the xylanase cocktail on xylan in the yellow corn of the feed showed a substantial collapse in the morphology of cell walls. Secondly, the reduction in the viscosity of the digesta of the feed by the cocktail showed an effective degradation of the soluble fraction of xylan. Analysis of the xylan degradation products from broiler feeds by the xylanase cocktail showed that xylotriose and xylopentaose were the major xylooligosaccharides (XOS) produced. In vitro evaluation of the prebiotic potential of these XOS showed that they improved the growth of the beneficial bacteria Streptococcus thermophilus and Lactobacillus bulgaricus. The antibacterial activity of broths from XOS-supplemented probiotic cultures showed a suppressive effect on the growth of the extraintestinal infectious bacterium Klebsiella pneumoniae. Supplementing the xylanase cocktail in cereal animal feeds attenuated xylan's antinutritional effects by reducing digesta viscosity and releasing entrapped nutrients. Furthermore, the production of prebiotic XOS promoted the growth of beneficial bacteria while inhibiting the growth of pathogens. Based on these effects of the xylanase cocktail on the feed, improved growth performance and better feed conversion can potentially be achieved during poultry rearing.

Fat deposition, fatty acid profiles, antioxidant capacity and differentially expressed genes in subcutaneous fat of Tibetan sheep fed wheat-based diets with and without xylanase supplementation

Xylanase, an exogenous enzyme that plays an essential role in energy metabolism by hydrolysing xylan into xylose, has been shown to positively influence nutrient digestion and utilisation in ruminants. The objective of this study was to evaluate the effects of xylanase supplementation on the back-fat thickness, fatty acid profiles, antioxidant capacity, and differentially expressed genes (DEGs) in the subcutaneous fat of Tibetan sheep. Sixty three-month-old rams with an average weight of 19.35 ± 2.18 kg were randomly assigned to control (no enzyme added, WH group) and xylanase (0.2% of diet on a dry matter basis, WE group) treatments. The experiment was conducted over 97 d, including 7 d of adaption to the diets. The results showed that xylanase supplementation in the diet increased adipocyte volume of subcutaneous fat (p < 0.05), shown by hematoxylin and eosin (H&E) staining. Gas chromatography showed greater concentrations of C14:0 and C16:0 in the subcutaneous fat of controls compared with the enzyme-treated group (p < 0.05), while opposite trend was seen for the absolute contents of C18:1n9t, C20:1, C18:2n6c, C18:3, and C18:3n3 (p < 0.05). Compared with controls, supplementation with xylanase increased the activity of T-AOC significantly (p < 0.05). Transcriptomic analysis showed the presence of 1630 DEGs between the two groups, of which 1023 were up-regulated and 607 were down-regulated, with enrichment in 4833 Gene Ontology terms, and significant enrichment in 31 terms (p < 0.05). The common DEGs were enriched in 295 pathways and significantly enriched in 26 pathways. Additionally, the expression of lipid-related genes, including fatty acid synthase, superoxide dismutase, fatty acid binding protein 5, carnitine palmytoyltransferase 1 A, and peroxisome proliferator-activated receptor A were verified via quantitative reverse-transcription polymerase chain reaction. In conclusion, dietary xylanase supplementation was found to reduce subcutaneous fat deposition in Tibetan sheep, likely through modulating the expression of lipid-related genes.

Supplementation of amylase or amylase + xylanase improves performance and metabolism of broilers fed with diets containing newly harvested maize

How supplementation with amylase or amylase + xylanase in newly harvested maize-based diets affects broiler nutrient metabolism and performance is unclear. Thus, this study evaluated whether the supplementation of amylase (CN) or amylase + xylanase (CAX) improves performance and metabolism of broilers fed with newly harvested maize-based diets during a 6-week production. The results showed that the body weight gain of broilers fed with CA or CAX diet was higher than that with the control (CN) diet at 1-21 d of age; however, an opposite trend was observed for feed/gain (p < 0.05). Furthermore, 150, 64 and 35 different metabolites were found between CA/CN, CAX/CN and CAX/CA, respectively. Overall, amylase supplementation improved broiler growth performance at 1-21 d of age, and the positive effects of amylase on nutrient utilization were mostly related to nicotinate, retinol and glutathione metabolism improvement. Moreover, CAX diet increased apparent metabolizable energy and growth performance of broilers at 22-42 d of age, and the difference might be related to sphingolipid, porphyrin and chlorophyll metabolism regulation. The findings prove amylase + xylanase supplementation is an effective method to improve the nutritional value of newly harvested maize for broilers.

In vitro evaluation of efficacy of nonstarch polysaccharides enzymes on wheat by simulating the avian digestive tract

In this study, the efficacy of different nonstarch polysaccharide (NSP) enzyme sources on wheat ingredients and wheat basal diets in vitro were evaluated by simulating the avian digestive tract. In Exp. 1, pH level was increased from 2.0 to 8.0 by simulating the avian digestive tract. The relative enzyme activities of xylanase A, B, and C and β-glucanase X at pH 3.0-3.5 were higher (P < 0.05) than those at pH 2.0 or 7.0-8.0. The optimal pH levels of 3.5 and 7.0 were screened by simulating the proventriculus and small intestine, respectively to evaluate the efficacy of NSP enzyme on wheat sources. In Exp. 2, wheat 1 contained the highest content of NSP fractions and the lowest digestibility in vitro dry matter (IVDMD) and energy (IVED) in wheat samples. Therefore, wheat 1 was selected for hydrolysis research under different NSP enzyme sources and levels (1,500, 4,500, 13,500, 40,500, 121,500 U xylanase/kg and 250, 500, 1,000, 2,000, 4,000 U β-glucanase/kg) in vitro. The hydrolysis of wheat on the basis of the released reducing sugar content was determined by xylanase sources A > B > C (P < 0.05) and β-glucanase sources of X > Y (P < 0.05). On the basis of the hydrolysis, the optimum dose of xylanase A and β-glucanase X were 40,500 U/kg and 2,000 U/kg, respectively. Subsequently, the completely randomized designs involving 2 NSP enzymes treatments × 2 endogenous digestive enzymes treatments (Exp. 3), as well as 2 wheat basal diets × 2 NSP enzymes treatments (Exp. 4) were used to evaluate the efficacy of NSP enzymes on dietary nutrient digestibility. The addition of NSP enzymes (40,500 U xylanase A/kg and 2,000 U β-glucanase X/kg) increased the IVDMD and IVED of wheat 1 without endogenous enzymes (P < 0.05), while the IVDMD and IVED of wheat 1 with endogenous enzyme were only slightly increased (P > 0.05). The addition of NSP enzymes could increase the IVDMD and IVED of corn-wheat-soybean meal diet (P < 0.05), but had no effect on those of wheat-cottonseed meal rapeseed meal diet (P > 0.05). In conclusion, xylanase and β-glucanase additions could effectively eliminate the adverse effects on wheat and wheat basal diets at the optimal pH levels of 3.5 and 7.0 by simulating the proventriculus and small intestine parts, respectively. The efficacy of NSP enzymes was influenced by the enzyme sources, dietary type, and the interaction of endogenous enzymes.

Exogenous enzymes, meal size, and meal frequency: effect on ileal and total tract digestibility of carbohydrates, and energy and fiber degradation in growing pigs fed a wheat-barley grain-based high-fiber diet

When conducting a digestibility trial, pigs are usually fed only twice a day with a restricted feed intake which is not representative of the feeding conditions in a commercial farm. This study aimed to determine the effects of meal size and frequency, and exogenous enzymes (xylanase and phytase) on the digestibility of a high-fiber diet using porcine in vivo and in vitro approaches. Pigs (n = 6) were fitted with a T cannula, and each received all treatments using a 6 × 6 Latin square experimental design. The diets were supplemented (Enz) or not with a combination of xylanase and phytase and distributed into three feeding programs: one received two meals per day that met three times the maintenance energy requirement (2M), one received the same quantity of feed in eight meals (8M), and another received an amount that met five times the maintenance energy requirements in eight meals (8M+). For in vitro experiment, the degradability of fiber with or without xylanase supplementation only was determined. Enzyme supplementation increased apparent ileal digestibility (AID) of dry matter, starch, and degradation of insoluble non-starch polysaccharides (I-NSP) in all in vivo treatments (P < 0.05). The 2M compared with 8M increased the AID of starch and total tract digestibility of organic matter and I-NSP (P < 0.05). Enzyme supplementation decreased the content of insoluble arabinoxylan (P < 0.05) and increased arabinoxylan oligosaccharides (P < 0.05) in the in vivo ileal digesta and in vitro incubation. The results of this study confirm degradation by xylanase of the fiber fraction at the ileal level, which resulted in less fermentation of fiber in the large intestine. However, number and size of meals had little influence on feed digestibility. The consequences of shifting fiber fermentation more towards the upper part of the gastrointestinal tract need further investigation. The in vitro model provided a confirmation of the action of xylanase on the degradation of non-starch polysaccharides.

Effects of xylanase on growth performance, nutrient digestibility, serum metabolites, and fecal microbiota in growing pigs fed wheat-soybean meal-based diets

This experiment investigated the effects of xylanase on growth performance, nutrient digestibility, serum metabolites, and fecal microbiota in growing pigs fed wheat-soybean meal-based diets. Seventy-two crossbred pigs (Duroc × [Landrace × Large White]) pigs (body weight of 23.30 ± 1.51 kg) were allotted two treatments with six pens per treatment and six pigs per pen. The diets were a wheat-soybean meal-based diet (Control group) and a wheat-soybean meal-based diet supplemented with 500 U/kg xylanases (XYL group). The experiment was divided into two periods (phase 1: days 1 to 35 and phase 2: days 36 to 70). Xylanase improved G:F during phase 1 and the entire experiment (P < 0.05) and tended to improve G:F during phase 2 (P = 0.09). Compared with the control group, pigs in the XYL group had greater apparent total tract digestibility of dry matter, organic matter, and gross energy on days 35 and 70 (P < 0.05) and had greater apparent ileal digestibility of amino acids (histidine, lysine, methionine, and serine) on day 70 (P < 0.05). The fecal microbiota in the XYL group contained greater abundances of g_Terrisporobacter, g_Lactobacillus, g_Clostridium_sensu_stricto_1, and g_Romboutsia than the Control group on day 70. Xylanase increased the fecal Lactobacillus populations on day 35 (P < 0.05). On days 35 and 70, xylanase reduced the fecal E. coli populations (P < 0.05). Supplementing xylanase to wheat-soybean meal-based diets collectively improved fecal microbiota, and nutrient digestibility, thereby improving growth performance in growing pigs.

Rapeseed meal processing and dietary enzymes modulate excreta inositol phosphate profile, nutrient availability and production performance of broiler chickens

This study aimed to assess the effect of rapeseed meal (RSM) processing method, where solvent extraction occurred under standard industry conditions (ST) or cold-pressed hexane extraction was employed (MT), and exogenous enzyme supplementation (phytase [PHY] and xylanase [XYL]) alone or in combination on key nutritional factors of broiler chickens. A randomized control experiment was performed using 144 male Ross 308 broilers in a 2 × 2 × 3 factorial arrangement. Three diets including a nutritionally complete wheat-based basal diet (BD), a diet containing 200 g/kg of RSM extracted under ST and another diet containing 200 g/kg of RSM extracted under MT were produced. Each diet was then split into 4 parts and was fed as is, or supplemented with PHY at 1,500 FTU/kg or XYL at 16,000 BXU/kg, alone or in combination, resulting in 12 diets in total. Response criteria: feed intake (FI), weight gain (WG), and feed conversion ratio (FCR), from 7 to 21 d age, AMEn, retention coefficients for dry matter (DMR), nitrogen (NR), fat (FR), and the profile of inositol phosphate esters (IP2-6) and myo-inositol (MI) in excreta. Diets containing MT had higher AMEn compared to ST diets (P < 0.05). There was RSM by PHY interaction for FI, as only birds fed MT diet responded to PHY supplementation with reduced FI and FCR (P < 0.001). Feeding XYL reduced overall FI and FCR (P < 0.05). Feeding PHY reduced IP6 and increased MI in excreta (P < 0.001). Feeding XYL and PHY in combination reduced MI in excreta compared to PHY only (P = 0.05). Compared to BD, birds fed RSM diets had an increased IP6 (P < 0.05) and MI concentration in excreta (P < 0.01). This may be due to IP ester differences in RSM and BD.

Exogenous phytase and xylanase supplementation of formulated diets for rohu (Labeo rohita): impact on haematology, histology and IGF I gene expression

The present study aims to delineate the effect of exogenous enzyme supplementation of fermented or non-fermented de-oiled rice bran (DORB) on haematology, histology and expression of IGF I gene expression of Labeo rohita. Four test diets, namely, T1 (DORB), T2 (fermented DORB), T3 (DORB+exogenous enzyme) and T4 (fermented DORB+exogenous enzyme) were formulated and fed to the L. rohita for a period of 60 days. The test diets T3 and T4 were supplemented with 0.1 g kg^-1 xylanase (16,000 U kg^-1) and 0.1 g kg^-1 phytase (500 U kg^-1) enzymes. A total of 120 juveniles of L. rohita (average weight 5.01 ± 0.02 g) were stocked in 12 rectangular tanks with 10 fish per tank in triplicates. At the end of the experiment, haematology, histology and IGF I gene expression of the different groups were analysed. The haemoglobin (Hb) content, RBC count and WBC count of L. rohita varied significantly (p < 0.05) among different groups. T3 diet-fed group had the highest Hb content, RBC count and WBC count as compared to the other groups. The MCV content was significantly (p < 0.05) lower in T3 group. The DORB type, exogenous enzyme supplementation and their interaction have no significant (p > 0.05) effect on MCH, MCHC and lymphocyte content of the cultured fish. The group which were fed T3 diet had significantly (p < 0.05) higher IGF-I gene expression as compared to other groups. The histological examination of liver revealed no pathological alteration of this organ. Similarly, there were no pathological changes observed in intestinal tissue in any dietary treatment group. Based on the findings of the present study, it is concluded that exogenous enzyme supplementation of DORB-based diets improves the physiological status and growth performances of Labeo rohita.

Effects of dietary exogenous xylanase supplementation on growth performance, intestinal health, and carbohydrate metabolism of juvenile large yellow croaker, Larimichthys crocea

An 8-week feeding trial was conducted to evaluate the effects of dietary xylanase supplementation on growth performance, digestive enzyme activity, intestinal morphology parameter, intestinal microbiome diversity, and carbohydrate metabolism for juvenile large yellow croaker (Larimichthys crocea). Four levels of xylanase were added to basal diets (0, 600, 1200, and 1800 U kg^-1). The results indicated that fish fed the 1200 U kg^-1 xylanase diet had higher weight gain than those fed the 0 and 600 U kg^-1 xylanase diet. The highest intestinal folds and microvillous height were observed at fish fed the 1200 U kg^-1 xylanase diet. High-throughput sequencing revealed that the majority of reads derived from the large yellow croaker digesta belonged to members of Proteobacteria followed by Chloroflex, Bacteroidetes, Spirochaetae, and Firmicute. Supplementation of xylanase in diets increased the relative abundance of Bacteroides and Gemmatimonadete. The higher hepatic glucokinase (GK) and glucose-6-phosphate dehydrogenase (G6PD) activities were observed in fish fed the xylanase supplementation diet. Accordingly, dietary xylanase supplementation upgraded the relative expressions of gk and g6pd genes in liver. In conclusion, optimum dietary xylanase supplementation (600-1200 U kg^-1) could improve the growth performance, optimize the intestinal morphology structure and microbiota constitution, and enhance the ability of carbohydrate utilization of juvenile large yellow croaker.

Effect of ammonia fiber expansion-treated wheat straw and a recombinant fibrolytic enzyme on rumen microbiota and fermentation parameters, total tract digestibility, and performance of lambs

The objective of this study was to evaluate the effect of ammonia fiber expansion (AFEX)-treated wheat straw pellets and a recombinant fibrolytic enzyme on the rumen microbiome, rumen fermentation parameters, total tract diet digestibility, and performance of lambs. Eight rumen cannulated wethers and 60 lambs (n = 15 per diet, 8 rams and 7 ewes) were used in a replicated 4 × 4 Latin square design digestibility study and a complete randomized growth performance study, respectively. Four treatment diets were arranged in a 2 × 2 factorial structure with AFEX wheat straw (0% or 30% AFEX straw pellets on a dietary DM basis replacing alfalfa hay pellets) and fibrolytic enzyme (with or without XYL10C, a β-1,4-xylanase, from Aspergillus niger) as main factors. Enzyme was applied at 100 mg/kg of diet DM, 22 h before feeding. Rumen bacteria diversity Pielou evenness decreased (P = 0.05) with AFEX compared with the control diet and increased (P < 0.01) with enzyme. Enzyme increased (P ≤ 0.02) the relative abundancies of Prevotellaceae UCG-004, Christensenellaceae R-7 group, Saccharofermentans, and uncultured Kiritimatiellaeota. Total protozoa counts were greater (P ≤ 0.04) in the rumen of lambs fed AFEX compared with control, with enzyme reducing (P ≤ 0.05) protozoa counts for both diets. Digestibility of DM did not differ (P > 0.10) among diets, but digestibility of CP was reduced (P = 0.001), and digestibility of NDF and ADF increased (P < 0.05) as AFEX replaced alfalfa. Compared with control, AFEX promoted greater DMI (P = 0.003) and improved ADG up to 42 d on feed (P = 0.03), but not (P = 0.51) over the full ~94-d experiment. Consequently, overall G:F was reduced (P = 0.04) for AFEX when compared with control (0.188 vs. 0.199), but days on feed were lower (P = 0.04) for AFEX (97 vs. 91 d). Enzyme improved DMI of AFEX up to day 70 (P = 0.01), but did not affect DMI of the control diet. Enzyme addition improved ADG of lambs fed both diets in the first 28 d (P = 0.02), but not over the entire feeding period (P ≥ 10). As a result, G:F was improved with enzyme for the first 28 d (P = 0.04), but not overall (P = 0.45). This study shows that AFEX-treated wheat straw can replace alfalfa hay with no loss in lamb growth performance. Additionally, the enzyme XYL10C altered the rumen microbiome and improved G:F in the first month of the feeding.

Effect of dietary supplementation of xylanase in a wheat-based diet containing canola meal on growth performance, nutrient digestibility, organ weight, and short-chain fatty acid concentration in digesta when fed to weaned pigs

This study was designed to determine the effect of dietary supplementation of xylanase on growth performance, nutrient digestibility, organ weight, digesta pH, and concentration of short-chain fatty acids (SCFA) of weaned pigs fed wheat-canola meal (CM) diets over a 35-d period. A total of 144 piglets (72 barrows and 72 gilts) weaned at 18 ± 2 d of age, with initial body weight (BW) of 6.2 ± 0.7 kg, received one of eight dietary treatments based on randomized complete block design. BW and feed intake were recorded weekly to calculate average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency (G:F). Treatments consisted of a control wheat-soybean meal-based diet and wheat-regular (RCM), dehulled (DCM), or coarse CM (CCM) without and with 16,000 BXU/kg xylanase (Econase XT). All diets contained 500 FTU/kg of phytase (Quantum Blue 5G) and titanium dioxide (0.3%). Apparent total tract digestibility (ATTD) of neutral detergent fiber (NDF), crude protein (CP), phosphorous (P), calcium (Ca), dry matter, and diet were determined. On day 35, one pig per pen was euthanized to evaluate the main factors of protein, xylanase supplementation, and sex on organ weight, ileal and colon digesta pH, and colon digesta concentrations of SCFA. The main factors did not affect growth performance. Xylanase supplementation improved nutrient digestibilities in all diets and increased ileal and colonic digesta pH without affecting the growth performance of weaned pigs fed wheat and CM-based diets. A protein-xylanase effect (P < 0.05) resulted in increasing the ATTD of NDF from 28% to 32% and from 29% to 37% for RCM and DCM, respectively. The ATTD of CP was greater (P < 0.05) with xylanase supplementation (75% vs. 70%). Xylanase supplementation increased ATTD of P and Ca. A three-way interaction (P < 0.05) for protein-xylanase-gender for colon pH, acetic, and propionic acid in the colon digesta of pigs indicated that, in addition to the protein source, piglet sex could have influenced how xylanase works. Xylanase supplementation increased (P < 0.05) the weight of the liver and spleen and tended (P < 0.10) to increase the size of the kidney. In conclusion, dietary supplementation of xylanase increased nutrient digestibility and digesta pH but did not influence the growth performance of weaned pigs fed wheat and CM-based diets over a 35-d period.

Xylanase, and the role of digestibility and hindgut fermentation in pigs on energetic differences among high and low energy corn samples1

The experimental objective was to evaluate the digestibility and fermentation differences between high and low energy corn samples and their response to xylanase supplementation. Four corn samples, 2 with higher DE content (HE-1 and HE-2; 3.74 and 3.75 Mcal DE/kg DM, respectively) and 2 with a lower DE content (LE-1 and LE-2; 3.63 and 3.56 Mcal DE/kg DM, respectively) were selected based upon a previous digestibility trial. Sixteen individually housed barrows (PIC 359 × C29; initial BW = 34.8 ± 0.23kg) were surgically fitted with an ileal T-cannula and randomly allotted to treatments in an 8 × 4 Youden square design. Dietary treatments were arranged in a 4 × 2 factorial: HE-1, HE-2, LE-1, and LE-2, with and without xylanase supplementation. Diets were formulated using one of the 4 corn samples, casein, vitamins, minerals, and 0.4% chromic oxide as an indigestible marker. Feed intake was established at approximately 3 times the estimated energy required for maintenance (NRC 2012) based upon the average initial BW of the pigs at the start of each collection period, which consisted of 9 d adaptation, 2 d of fecal, and 3 d of ileal collections. Diets, ileal, and fecal samples were analyzed for DM, GE, and total dietary fiber (TDF), to determine apparent total tract (ATTD), hindgut fermentation (HF), apparent ileal digestibility (AID) coefficients. A diet × enzyme interaction was not observed for any of the measured variables (P > 0.10). The HE-1 and HE-2 diets had greater ATTD of GE, and HE-2 diet had greater ATTD of DM (P < 0.001 and P = 0.007, respectively). Xylanase, independent of diet, improved the ATTD of GE and DM (84.8 vs. 83.6% for GE with and without enzyme, respectively, P = 0.008; and 84.2 and 83.0% with and without enzyme, respectively, P = 0.007). The energetic differences among these corn samples appeared to be driven by fermentability in the hindgut. Supplementing xylanase improves digestibility irrespective of the digestibility energy content of corn.

Effect of age on the relationship between metabolizable energy and digestible energy for broiler chickens

A total of 960 male Ross 308 chicks (day-old) were used to investigate the effect of age on the relationship between metabolizable energy (ME) and digestible energy (DE) for broiler chickens. Bird growth variables, nitrogen retention (NR), nitrogen digestibility (ND), as well as the relative weight of liver, pancreas, and the gastrointestinal tract were determined. Practical diets that compared 2 cereals (corn and wheat) and exogenous xylanase (0 or 16,000 BXU/kg) were evaluated at 5 ages (7, 14, 21, 28, and 35 D) in a 2 × 2 × 5 factorial arrangement of treatments with 8 replicates per treatment and started with 30 birds per replicate. A randomized block ANOVA analysis of repeated measures was performed, and a 2 × 2 × 5 factorial structure was used to investigate the 2 dietary treatment factors (cereal type and the presence of xylanase) within the 5 bird ages (7, 14, 21, 28, and 35 D), and their interactions. Apparent metabolizable energy (AME) increased linearly from 7 until 28 D of age, but (P < 0.05) decreased at 35 D of age. Digestible energy was high at 7 D of age, then dropped and remained similar (P > 0.05) from 14 to 35 D of age. The AME: DE ratio was lowest (P < 0.05) at 7 D of age but there were no (P > 0.05) differences thereafter. Cereal type and xylanase supplementation did not (P > 0.05) change the ME: DE ratio. The results indicate that determining ME before 14 D of age may give absolute values that are lower than would be obtained with older birds. ME values that are determined on older broiler chickens may overestimate the energy availability of practical feeds used in broiler starter feeds.

Effects of a recombinant fibrolytic enzyme on fiber digestion, ruminal fermentation, nitrogen balance, and total tract digestibility of heifers fed a high forage diet1

A metabolism study was conducted using 8 ruminal cannulated beef heifers to investigate the effects of a recombinant fibrolytic enzyme (RFE; xylanase XYL10C) selected specifically for forage-fed ruminants on ruminal pH, fermentation, nitrogen balance, and total tract digestibility of heifers. The experiment was a cross-over design with 2 treatments and 2 periods. The 2 treatments were a basal diet containing 60% barley silage, 30% barley straw, and 10% supplement (DM basis) without (control) or with RFE. The enzyme was sprayed onto the barley straw at a rate of 6.6 × 104 IU·kg-1 DM 24 h before feeding. Each period comprised 2 wk of diet adaptation and 1 wk of sampling and data collection. Feed intake and total tract digestibility of DM, OM, NDF, and ADF were unaffected by RFE. Ruminal pH including mean, minimum, maximum, and duration pH <5.8, did not differ between treatments. Total VFA concentration, molar proportion of individual VFA, and acetate-to-propionate ratio were also not affected by RFE. However, ruminal NH3-N concentration (P < 0.06) and endoglucanase activity (P < 0.08) in ruminal fluid tended to be higher with RFE. Nitrogen utilization and microbial protein synthesis were not affected by treatment. These results indicate that XYL10C did not improve fiber digestion in heifers fed a high forage diet, despite the fact that it was specifically selected for this trait in laboratory assays. However, the increased ruminal NH3-N concentration suggests it potentially increased ruminal proteolytic activity.

Degradation of dietary fiber in the stomach, small intestine, and large intestine of growing pigs fed corn- or wheat-based diets without or with microbial xylanase

An experiment was conducted to test the hypothesis that microbial xylanases may contribute to the degradation of fiber in wheat and wheat-based diets and in corn and corn-based diets along the intestinal tract of pigs. Twenty-four growing barrows (initial BW: 28.51 ± 1.86 kg) were prepared with a T-cannula in the proximal duodenum and another T-cannula in the distal ileum and allotted to a replicated 12 × 4 Youden square design with 12 diets and four 18-d periods. Two diets based on corn and soybean meal (SBM) or corn, SBM, and 30% distillers dried grains with solubles (DDGS) were formulated and two diets based on wheat and SBM or wheat, SBM, and 30% wheat middlings were also formulated. The four diets were formulated without microbial xylanase, or with one of two microbial xylanases (xylanase A or xylanase B) for a total of 12 diets. Feces and urine were collected on days 8 to 13, ileal digesta were collected on days 15 and 16, and duodenal digesta were collected on days 17 and 18 of each period. The apparent duodenal digestibility (ADD), apparent ileal digestibility (AID), and apparent total tract digestibility (ATTD) of GE, nutrients, and dietary fiber were calculated. Results indicated that the AID of GE in corn-SBM or wheat-SBM diets was greater (P < 0.05) than in the corn-SBM-DDGS and wheat-SBM-wheat middlings diets, but no difference was observed for the AID of dietary fiber between wheat-SBM and wheat-SBM-wheat middlings diets. The ATTD of dietary fiber was also greater (P < 0.05) in corn-SBM and wheat-SBM diets compared with corn-SBM-DDGS and wheat-SBM-wheat middlings diets, which indicates that the concentration of dietary fiber may influence the degree of fermentation of fiber. Inclusion of xylanase A or B improved (P < 0.05) the ADD and the ATTD of dietary fiber in wheat-based diets, indicating activity of xylanase in the gastro-intestinal tract of pigs. Inclusion of xylanase A improved (P < 0.05) the concentration of DE and ME in wheat-SBM-wheat middlings diets and xylanase B improved (P < 0.05) the concentration of DE in wheat-based diets and improved (P < 0.05) the concentration of the ME in wheat-SBM diet. In conclusion, the xylanases used in this experiment improved the digestibility of dietary fiber in the stomach and hindgut and improved the energy status of pigs fed wheat-based diets, but not of pigs fed corn-based diets.

Effects of mono-component xylanase supplementation on nutrient digestibility and performance of lactating sows fed a coarsely ground diet

The objective of the current study was to investigate the effect of supplementing a mono-component xylanase to a coarsely ground lactation diet (feed fraction particle size above 2 mm was more than 17%) based on wheat, barley, and soybean meal on nutrient digestibility and performance of lactating sows. A total of 30 cross-bred (Danish Landrace × Yorkshire) multiparous sows (parity 2 to 5) were used. Sows were fed a standard gestation diet from mating until day 108 of gestation, and then stratified for BW (295.4 ± 26.1 kg average BW) and parity to receive one of two dietary treatments (n = 15 per treatment), a lactation diet without (control diet) or with supplemented enzyme (enzyme diet). The enzyme applied was a mono-component xylanase dosed at 200 enzyme unit (FXU) per kg of feed, which corresponds to 200 g per ton of feed. The diets were fed until weaning at day 28 of lactation. On day 2 of lactation, litter size of each sow was adjusted to 14 piglets within treatment. Reproductive performance of the sows, growth of the piglets, yield and composition of sow milk, plasma metabolites and apparent total tract digestibility (ATTD) of nutrients were measured. Supplementation of xylanase had no effect (P > 0.05) on total born and live born piglets or stillbirth rate (%) at parturition. Initial parameters on day 2 of lactation including sow BW and back fat thickness, litter size, piglet weight, and litter weight were similar (P > 0.05) between treatments. Piglet weight gain, litter weight gain, litter size, and daily milk yield did not differ (P > 0.05) between treatments. The ADFI was increased by 4.5% (P < 0.01), and BW loss during the whole lactation was reduced from -13.6 to -5.2 kg (P = 0.04) with xylanase addition when compared to control sows. The ATTD of GE (83.9 vs. 82.9, P < 0.01), DM (84.2 vs. 83.4, P < 0.01), N (83.4 vs. 81.7, P = 0.02), OM (86.5 vs. 85.7, P < 0.01) and total nonstarch polysaccharides (NSP; 59.4 vs. 56.7, P = 0.02) were all increased by xylanase supplementation. Milk composition and plasma metabolites were not affected (P > 0.05), except that plasma triglycerides content was increased by xylanase addition (0.23 vs. 0.20 mM, P = 0.04). In conclusion, supplementing a mono-component xylanase to a coarsely ground lactating diet based on wheat, barley, and soybean meal improved sow feed intake and nutrient digestibility, thereby reducing sow BW loss throughout lactation, whereas milk yield and piglet performance were not affected.

Interaction between xylanase and phytase on the digestibility of corn and a corn/soy diet for broiler chickens

An experiment was carried out to evaluate the digestibility and metabolizability of corn and a corn/soy-based diet with the inclusion or not of xylanase and/or phytase in broilers. In the trial, 1,120 broiler chicks were distributed according to a completely randomized experimental design, consisting of 16 treatments, with 10 replicates of 7 birds each. Treatments were evaluated following a factorial arrangement (4 × 2 × 2), with 4 xylanase levels (zero, 50, 100, or 150 fungal β-xylanase units/kg; FXU), 2 phytase levels (zero or 1,000 phytase units/kg; FTU), and 2 diets (corn/soy or pure corn). The same basal diets were fed from one to 14 d post hatch for all birds, after which the experimental diets were provided until d 25. All birds were euthanized on d 25 for collection of ileal contents. Samples of feed, excreta, and ileal digesta were analyzed for determination of apparent ileal digestibility. The effect of xylanase on the coefficient of apparent dry matter metabolizability and apparent metabolizable energy was increased by the presence of phytase in the complete diet but not in the diet based on pure corn resulting in a diet*phytase*xylanase interaction (P < 0.01; P < 0.001, respectivaly). Equivalent effects were observed for the apparent coefficient of ileal protein digestibility in which xylanase effects were potentiated by the presence of phytase only in the complete diet, resulting in a significant 3-way interaction. In corn there was a limitation in improving digestibility when we added increasing levels of xylanase with phytase. Otherwise in the corn/soy-based diets, the enzymes were potencialized when they were added together. The fact that the effect of xylanase was enhanced by the presence of phytase in complete diets but not in pure corn may be associated with differences in substrate (arabinoxylan and/or phytate) concentration and presentation, diet nutrient balance, or other factors. It can be concluded that the interactive effects of xylanase and phytase can be substantial but may depend on the characteristics of the diet fed.

Energy and nutrient utilization of broiler chickens fed corn-soybean meal and corn-based diets supplemented with xylanase

A study was conducted to evaluate the effects of increased levels of a β-xylanase on energy and nutrient utilization of broiler chickens fed corn-soy diets. A total of 480 slow feathering Cobb × Cobb 500 male broilers were randomly distributed to 10 treatments having 8 replicates of 6 birds each. Birds were fed a common starter diet to d 14 post hatch (3,050 kcal/kg AMEn, 21.7% CP, 1.05% Ca, and 0.53% nPP). The experimental diets were provided afterwards until 25 d. Two experimental diets, a conventional corn/soy-based basal diet (CS) and the basal diet in which 40% of the diet was displaced by corn (CN), were fed as-is or supplemented with 50, 100, 150, or 200 fungal β-xylanase units (FXU)/kg. Dietary treatments were distributed factorially as a 2 × 5 arrangement. Samples of feed, excreta, and ileal digesta were analyzed for determination of ileal digestible energy (IDE), metabolizable energy, and total tract retention of protein and lipid. No interactions between diet and xylanase were observed. The CS diets had higher (P < 0.05) energy utilization and nutrient digestibility when compared to the CN diets. AMEn and IDE were improved (P < 0.05) by 192 and 145 kcal/kg, respectively, when diets were supplemented with 100 FXU/kg xylanase. The xylanase added to the CN diet led to quadratic increases (P < 0.05) in IDE (Y = - 0.014x(2) + 2.570x + 3,155; r(2) = 0.60) and in AMEn (Y = - 0.016x(2) + 3.982x + 3,155; r(2) = 0.68). Crude protein digestibility and AMEn were linearly increased (P < 0.05) when xylanase was added to the CN diet. In conclusion, energy utilization and digestibility of crude protein and dry matter increased with xylanase supplementation in corn/soy-based diets. When xylanase was tested in the CS diet, 92 and 124 FXU/kg maximized the energy release effect; however, the maximum energy response in the CN diet or corn was not achieved until 200 FXU/kg.

Effect of wheat dried distillers grains with solubles and fibrolytic enzymes on ruminal fermentation, digestibility, growth performance, and feeding behavior of beef cattle

Two experiments were conducted to evaluate the effect of wheat dried distillers grains with solubles (DDGS) and fibrolytic enzymes (FE) on ruminal fermentation, in situ ruminal and in vivo total tract digestibility, growth performance, and feeding behavior of growing beef cattle. In Exp. 1, 6 ruminally cannulated Angus heifers (average BW of 794 ± 44.2 kg) were used in a 6 × 6 Latin square design with 2 × 3 factorial arrangement of treatments. Treatments were a control diet consisting of 50% barley silage, 10% grass hay, and 40% barley grain-based concentrate (CON) and the CON with 15% DDGS substituted for barley grain (WDG) combined with either 0, 1, or 2 mL FE/kg diet DM, respectively. Inclusion of DDGS increased total tract digestibility of CP ( < 0.01), NDF ( = 0.04), and ADF ( = 0.03). Increasing FE linearly ( = 0.03) increased CP digestibility without affecting the digestibility of other nutrients. There were no effects of DDGS inclusion or FE on ruminal pH or VFA concentration except that propionate was greater ( = 0.04) with the WDG. In situ ruminal DM and NDF disappearance of barley silage was greater ( < 0.04) in heifers fed the WDG than in heifers fed the CON after 24 h of incubation. Increasing FE linearly ( = 0.03) increased in situ NDF disappearance of barley silage after 24 h of incubation. In Exp. 2, 120 weaned steers (initial BW of 289 ± 11.0 kg) were fed diets similar to those in Exp. 1. The steers fed the WDG had greater ( < 0.01) final BW, ADG, DMI, and G:F compared with steers fed the CON. Increasing FE did not alter ADG or G:F but tended ( < 0.07) to linearly decrease DMI. There were interactions ( < 0.02) between DDGS and FE on eating rate and the time spent at the feed bunk. Supplementing FE decreased ( < 0.01) time at the bunk and increased ( < 0.01) eating rate for steers fed the WDG but not for steers fed the CON. Eating rate ( < 0.01) and meal frequency ( = 0.02) were greater but eating duration was shorter ( < 0.01) for steers fed the WDG than for those fed the CON. These results indicate that inclusion of wheat DDGS in a growing diet increased total tract digestibility of NDF and CP and improved the feed efficiency of steers. Moreover, supplementation of FE in barley silage-based growing diets may also have the potential to increase profits, with the evidence of the trend for a decline on DMI without decreasing ADG when adding FE.

Effects of microbial xylanase on digestibility of dry matter, organic matter, neutral detergent fiber, and energy and the concentrations of digestible and metabolizable energy in rice coproducts fed to weanling pigs

The objective of this experiment was to test the hypothesis that the apparent total tract digestibility (ATTD) of DM, OM, fiber, and GE by weanling pigs and the concentration of DE and ME in full-fat rice bran (FFRB), defatted rice bran (DFRB), brown rice, and broken rice is improved if microbial xylanase is added to the diet. Eighty pigs (13.6 ± 0.8 kg initial BW) were allotted to 10 diets with 8 replicate pigs per diet in a randomized complete block design with 2 blocks of 40 pigs. A basal diet based on corn and soybean meal and 4 diets containing corn, soybean meal, and each of the 4 rice coproducts were formulated. The rice coproducts and corn and soybean meal were the only sources of energy in the diets. Five additional diets that were similar to the initial 5 diets with the exception that they also contained 16,000 units of xylanase (Econase XT-25; AB Vista, Marlborough, UK) were also formulated. All diets also contained 1,500 units of microbial phytase (Quantum Blue 5G; AB Vista). The DE and ME and the ATTD of DM, OM, fiber, and GE in diets and ingredients were calculated using the direct method and the difference method, respectively. Results indicated that the concentrations of DE and ME (DM basis) in FFRB and DFRB increased ( < 0.05) if xylanase was used. Broken rice had a greater ( < 0.05) concentration of DE and ME than FFRB and DFRB if no xylanase was added to the diets, but if xylanase was used, no differences in ME among FFRB, brown rice, and broken rice were observed. The ATTD of DM was greater ( < 0.05) in ingredients with xylanase than in ingredients without xylanase and there was a tendency ( = 0.067) for the ATTD of OM to be greater if xylanase was used. The ATTD of NDF in FFRB was greater ( < 0.05) when xylanase was added than if no xylanase was used, whereas the ATTD of NDF in DFRB was not affected by the addition of xylanase. In conclusion, if no xylanase was used, broken rice and brown rice have greater concentrations of DE and ME than FFRB and DFRB, and these values were not increased by microbial xylanase. However, xylanase increased the concentration of DE and ME (DM basis) in FFRB and DFRB.

Xylanase increased the ileal digestibility of nonstarch polysaccharides and concentration of low molecular weight nondigestible carbohydrates in pigs fed high levels of wheat distillers dried grains with solubles

The objective was to study the effect of a commercially available xylanase (CAX), an experimental xylanase (EX), and EX in combination with protease (EXP) on the degradation of nondigestible carbohydrates (NDC) and apparent ileal digestibility (AID) of nutrients in wheat distillers dried grains with solubles (wDDGS). The control and 3 enzyme diets contained 96% wDDGS supplemented with vitamins, minerals, L-lysine, and chromic oxide as a digestibility marker in addition to enzyme premix. Eight ileal cannulated pigs were fed 4 experimental diets containing 96% wDDGS-a control diet or 1 of 3 diets with CAX, EX, or EXP-in a double 4 × 4 Latin square design. The experimental period lasted 7 d; adaptation lasted 4 d, and the ileal digesta were collected for 8 h on d 5 and 7, when spot samples of feces were also collected. Digesta samples were analyzed for NDC, total and soluble nonstarch polysaccharides (NSP), low molecular weight (LMW) NDC, OM, CP, fat, starch, and marker. Compared with the control diet, addition of CAX, EX, and EXP increased the AID of arabinoxylan by 32 (P < 0.001), 28 (P = 0.001), and 24% (P = 0.004), respectively. In addition, EXP increased the AID of noncellulosic polysaccharide glucose by 21% compared with the control (P = 0.005). Compared with the control, addition of EX, EXP, and CAX decreased the concentration of soluble arabinoxylan in ileal digesta by 40 (P < 0.0001), 40 (P < 0.0001), and 21% (P = 0.022), respectively. Furthermore, addition of CAX, EXP, and EX increased the concentration of LMW arabinoxylan in ileal digesta by 40 (P = 0.0001), 36 (P = 0.0006), and 24% (P = 0.023), respectively, compared with the control. Addition of EX and EXP decreased the concentration of soluble NSP of ileal digesta by 25 (P = 0.001) and 26% (P < 0.001), respectively, compared with the control diet. Addition of CAX (P < 0.0001) and EXP (P = 0.013) increased the arabinose-to-xylose ratio in the insoluble arabinoxylan fraction in ileal digesta compared with the control diet, and CAX increased the uronic acid-to-xylose ratio of the ileal insoluble NSP fraction (P < 0.0001) compared with the control diet. Enzyme addition did not affect AID of OM, CP, starch, and fat (P > 0.3). In conclusion, addition of xylanases to wDDGS diets increased the ileal digestibility of NSP and generated LMW NDC components in the small intestine of pigs but did not affect ileal digestibility of nutrients in the current study.

Fermentation and addition of enzymes to a diet based on high-moisture corn, rapeseed cake, and peas improve digestibility of nonstarch polysaccharides, crude protein, and phosphorus in pigs

Fluctuating prices of cereals have led to an interest in alternative ingredients for feed. The aim of this study was to evaluate the effect of fermentation and the addition of nonstarch polysaccharide (NSP)-degrading enzymes on the ileal and total tract digestibility of nutrients of a diet based on locally grown crops. Four diets were fed including a nonfermented liquid standard grower diet (Control) and 3 experimental diets based on high-moisture corn, rapeseed cake, and peas fed as nonfermented liquid feed (nFLF), fermented liquid feed (FLF), or FLF supplemented with an enzyme mixture of β-glucanase + xylanase + pectinase (FLF+Enz). The FLF was prepared by mixing feed and water (1:2.5, wt/wt) and, once daily, replacing 50% of the mixture with an equal amount of fresh feed and water. The diets were fed to 8 ileal cannulated barrows in a double Latin square design. Ileal digesta and feces were collected after an adaption period of 10 d. Results showed microbiologically good-quality fermented diets. The levels of Enterobacteriaceae were 5.1 to 5.4 log cfu/g in FLF and FLF+Enz vs. 6.3 log cfu/g in nFLF in the ileum and 5.1 to 5.2 log cfu/g in FLF and FLF+Enz vs. 6.3 log cfu/g in nFLF in the feces. Apparent total tract digestibility (ATTD) of CP was increased by fermentation (73.2% in FLF vs. 69.0% in nFLF; P = 0.033), and digestibility of P showed a tendency (P = 0.073) toward an increase. Addition of the enzyme mixture resulted in a pronounced reduction of dietary NSP compared with FLF (12.8% total NSP in FLF+Enz vs. 15.9% total NSP in FLF; P< 0.001), which also led to increased apparent ileal digestibility (AID) of total and insoluble NSP (total NSP, 31.1% in FLF+Enz vs. 13.6% in FLF; P = 0.002). The Control did not, in general, show higher digestibility values than the experimental diet. However, in the cases were it did, fermentation and enzyme addition brought the digestibility to the level of the Control. In conclusion, fermentation increased the ATTD of CP and the AID of P, with the same tendency (P ≤ 0.07) for the ATTD. Addition of NSP-degrading enzymes resulted in a pronounced reduction in the concentration of NSP in the feed along with increased AID of NSP. Hence, the experimental diet seems to be a possible alternative to a traditional diet for pigs.

Enhanced sugar production from pretreated barley straw by additive xylanase and surfactants in enzymatic hydrolysis for acetone-butanol-ethanol fermentation

This study aims to improve enzymatic sugar production from dilute sulfuric acid-pretreated barley straw for acetone-butanol-ethanol (ABE) fermentation. The effects of additive xylanase and surfactants (polyethylene glycol [PEG] and Tween) in an enzymatic reaction system on straw hydrolysis yields were investigated. By combined application of 2g/100g dry-matter (DM) xylanase and PEG 4000, the glucose yield was increased from 53.2% to 86.9% and the xylose yield was increased from 36.2% to 70.2%, which were considerably higher than results obtained with xylanase or surfactant alone. The ABE fermentation of enzymatic hydrolysate produced 10.8 g/L ABE, in which 7.9 g/L was butanol. The enhanced sugar production increased the ABE yield from 93.8 to 135.0 g/kg pretreated straw. The combined application of xylanase and surfactants has a large potential to improve sugar production from barley straw pretreated with a mild acid and that the hydrolysate showed good fermentability in ABE production.

Energy utilization and growth performance of chickens fed novel wheat inbred lines selected for different pentosan levels with and without xylanase supplementation

Different F5 recombinant inbred lines from the cross Yumai 34×Ukrainka were grown in replicated trials on a single site in one harvest year at Rothamsted Research. A total of 10 samples from those lines were harvested and used in a broiler experiment. Twenty nutritionally complete meal-form diets that had 630 g/kg of wheat with different amounts of pentosan, with and without exogenous xylanase supplementation, were used to compare broiler growth performance and determine apparent metabolizable energy corrected for N retention (AMEn). We examined the relationship between the nutritive value of the wheat samples and their chemical compositions and results of quality tests. The amounts of total and water soluble pentosans in wheat samples ranged from 36.7 to 48.0 g/kg DM, and 6.7 to 11.6 g/kg DM, respectively. The mean crude oil and protein contents of the wheat samples were 10.5 and 143.9 g/kg DM, respectively. The average determined value for the kinematic viscosity was 0.0018 mPa.s, and 2.1 mPa.s for the dynamic viscosity. The AMEn of the wheat-based diets had a maximum range of 0.47 MJ/kg DM within the ten wheat samples that were tested. Xylanase supplementation improved (P<0.05) dietary AMEn, dry matter, and fat digestibility coefficients. There was a positive (P<0.05) relationship between in vitro kinematic viscosity of the wheat samples and the total pentosan content. There was a negative relationship between the total pentosan content in the wheat and broiler growth performance. An increase by 10 g of pentosan per kg of wheat reduced (P<0.001) daily feed intake and weight gain by 2.9 g and 3.5 g, respectively. The study shows that the feeding quality of wheat samples can be predicted by their total pentosan content. Supplementary xylanase improved energy and nutrient availability of all wheat samples that was independent of differences in pentosan content.

Addition of feruloyl esterase and xylanase produced on-site improves sugarcane bagasse hydrolysis

Accessory enzymes that assist biomass degradation could be used to improve the recovery of fermentable sugar for use in biorefineries. In this study, different fungal strains isolated from the Amazon rainforest were evaluated in terms of their ability to produce feruloyl esterase (FAE) and xylanase enzymes, and an assessment was made of the contributions of the enzymes in the hydrolysis of pretreated sugarcane bagasse. In the selection step, screening using plate assays was followed by shake flask submerged cultivations. After carbon source selection and cultivation in a stirred-tank bioreactor, Aspergillusoryzae P21C3 proved to be a promising strain for production of the enzymes. Supplementation of a commercial enzyme preparation with 30% (v/v) crude enzymatic complex from A. oryzae P21C3 increased the conversion of cellulose derived from pretreated sugarcane bagasse by 36%. Supplementation with FAE and xylanase enzymes produced on-site can therefore be used to improve the hydrolysis of sugarcane bagasse.

Xylanase supplementation improves the nutritive value of diets containing high levels of sorghum distillers' dried grains with solubles for broiler chickens

BACKGROUND

An experiment was conducted to investigate the effect of sorghum distillers' dried grains with solubles (sDDGS) and xylanase supplementation in broiler chicken diets. A total of 432 Cobb-500 day-old male broiler chicks were used in a 4 × 2 factorial design (0, 100, 200 or 300 g kg(-1) sDDGS with or without xylanase supplementation). Each treatment was replicated six times with nine birds per replicate in a 35 day study.

RESULTS

Feed intake was increased (P < 0.001) throughout the study with the inclusion of dietary sDDGS. Body weight gain (BWG) was unaffected except for the last 2 weeks of study, when birds that received 200 and 300 g kg(-1) sDDGS had higher (P < 0.001) BWG. Feed conversion ratio (FCR) increased (P < 0.05) as sDDGS in the diet rose to 100 g kg(-1) during the starter phase and the whole period of study. Over the starter period, xylanase supplementation improved (P < 0.05) FCR, particularly for the highest inclusion of sDDGS. Protein digestibility deteriorated (P < 0.001) as sDDGS in the diet rose to 300 g kg(-1) . Xylanase reduced (P < 0.001) the concentration of xylose in the ileum of birds. The activities of sucrase and maltase in the jejunal mucosa were reduced when birds were offered 200 and 300 g kg(-1) sDDGS. Incorporation of sDDGS increased (P < 0.01) the total short-chain fatty acid concentration in the caeca.

CONCLUSION

The results showed that diets containing large amounts of sDDGS will benefit from xylanase supplementation, particularly in terms of FCR.

Dual function of novel pollen coat (surface) proteins: IgE-binding capacity and proteolytic activity disrupting the airway epithelial barrier

Background

The pollen coat is the first structure of the pollen to encounter the mucosal immune system upon inhalation. Prior characterizations of pollen allergens have focused on water-soluble, cytoplasmic proteins, but have overlooked much of the extracellular pollen coat. Due to washing with organic solvents when prepared, these pollen coat proteins are typically absent from commercial standardized allergenic extracts (i.e., “de-fatted”), and, as a result, their involvement in allergy has not been explored.

Methodology/Principal Findings

Using a unique approach to search for pollen allergenic proteins residing in the pollen coat, we employed transmission electron microscopy (TEM) to assess the impact of organic solvents on the structural integrity of the pollen coat. TEM results indicated that de-fatting of Cynodon dactylon (Bermuda grass) pollen (BGP) by use of organic solvents altered the structural integrity of the pollen coat. The novel IgE-binding proteins of the BGP coat include a cysteine protease (CP) and endoxylanase (EXY). The full-length cDNA that encodes the novel IgE-reactive CP was cloned from floral RNA. The EXY and CP were purified to homogeneity and tested for IgE reactivity. The CP from the BGP coat increased the permeability of human airway epithelial cells, caused a clear concentration-dependent detachment of cells, and damaged their barrier integrity.

Conclusions/Significance

Using an immunoproteomics approach, novel allergenic proteins of the BGP coat were identified. These proteins represent a class of novel dual-function proteins residing on the coat of the pollen grain that have IgE-binding capacity and proteolytic activity, which disrupts the integrity of the airway epithelial barrier. The identification of pollen coat allergens might explain the IgE-negative response to available skin-prick-testing proteins in patients who have positive symptoms. Further study of the role of these pollen coat proteins in allergic responses is warranted and could potentially lead to the development of improved diagnostic and therapeutic tools.

Ultrastructure of the innermost surface of differentiating normal and compression wood tracheids as revealed by field emission scanning electron microscopy

The ultrastructure of the innermost surface of Cryptomeria japonica differentiating normal wood (NW) and compression wood (CW) was comparatively investigated by field emission electron microscopy (FE-SEM) combined with enzymatic degradation of hemicelluloses. Cellulose microfibril (CMF) bundles were readily observed in NW tracheids in the early stage of secondary cell wall formation, but not in CW tracheids because of the heavy accumulation of amorphous materials composed mainly of galactans and lignin. This result suggests that the ultrastructural deposition of cell wall components in the tracheid cell wall differ between NW and CW from the early stage of secondary cell wall formation. Delignified NW and CW tracheids showed similar structural changes during differentiating stages after xylanase or β-mannanase treatment, whereas they exhibited clear differences in ultrastructure in mature stages. Although thin CMF bundles were exposed in both delignified mature NW and CW tracheids by xylanase treatment, ultrastructural changes following β-mannanase treatment were only observed in CW tracheids. CW tracheids also showed different degradation patterns between xylanase and β-mannanase. CMF bundles showed a smooth surface in delignified mature CW tracheids treated with xylanase, whereas they had an uneven surface in delignified mature CW tracheids treated with β-mannanase, indicating that the uneven surface of CMF bundles was related to xylans. The present results suggest that ultrastructural deposition and organization of lignin and hemicelluloses in CW tracheids may differ from those of NW tracheids.

Phosphatidylinositol 4-phosphate accumulates extracellularly upon xylanase treatment in tomato cell suspensions

Various phosphoinositides have been implicated in plant defence signalling. Until now, such molecules have been exclusively related to intracellular signalling. Here, evidence is provided for the detection of extracellular phosphatidylinositol 4-phosphate (PI4P) in tomato cell suspensions. We have analysed and compared the intracellular and extracellular phospholipid profiles of [(32)P(i)]-prelabelled tomato cells, challenged with the fungal elicitor xylanase. These phospholipid patterns were found to be different, being phosphatidylinositol phosphate (PIP) the most abundant phospholipid in the extracellular medium. Moreover, while cells responded with a typical increase in phosphatidic acid and a decrease in intracellular PIP upon xylanase treatment, extracellular PIP level increased in a time- and dose-dependent manner. Using two experimental approaches, the extracellular PIP isoform was identified as PI4P. Addition of PI4P to tomato cell suspensions triggered the same defence responses as those induced by xylanase treatment. These include production of reactive oxygen species, accumulation of defence-related gene transcripts and induction of cell death. We demonstrate that extracellular PI4P is accumulated in xylanase-elicited cells and that exogenous application of PI4P mimics xylanase effects, suggesting its putative role as an intercellular signalling molecule.

The effects of xylanase supplementation on growth, digestion, circulating hormone and metabolite levels, immunity and gut microflora in cockerels fed on wheat-based diets

1. The xylanase product used in this study was derived from a genetically modified isolate of Aspergillus niger. Two trials were conducted to investigate the effects of xylanase supplementation on growth, digestion, circulating hormone and metabolite levels, immune parameters and composition of the gut microflora in cockerels fed on wheat-based diets. 2. The experimental diets consisted of a wheat-based control diet supplemented with 0 or 0.1% enzyme preparation. The diets were fed between 7 and 21 d of age. 3. Enzyme supplementation improved growth and feed conversion efficiency. The addition of enzyme to wheat-based diet increased the apparent total digestibility of dry matter (DM), crude protein and fat. 4. Enzyme supplementation reduced the relative weight of digestive organs to a certain extent, but there was no significant difference. Enzyme supplementation reduced digesta viscosity in the jejunum. There was no significant difference between the two experimental groups in counts of lactobacillus and coliform bacteria in the caeca. 5. Enzyme supplementation increased the concentration of blood thyroxine (T(4)), insulin-like growth factor I (IGF-I) and insulin, reduced the concentrations of blood uric acid, but had no significant effect on the concentrations of blood glucose and triiodothyronine (T(3)). 6. Enzyme supplementation increased the relative weight of spleen of cockerels, serum antibody titres to Newcastle disease virus (NDV), lymphocyte proliferation in response to phytohaemagglutinin (PHA) and the natural killer (NK) cell activity. 7. It is concluded that supplementation with an enzyme preparation (xylanase), which hydrolyses non-starch polysaccharides can improve growth in cockerels fed on wheat-based diets. This improvement is achieved through enzyme effects on digestion, absorption, metabolism and immunity of cockerels.

The Effect of Feeding a Dry Enzyme Mixture with Fibrolytic Activity on the Performance of Lactating Cows and Digestibility of a Diet for Sheep

A dry enzyme mixture was added to the diets of lactating cows and growing lambs to evaluate its ability to improve milk production and nutrient digestibility, respectively. The enzyme mixture contained xylanase and cellulase activity over a broad range of pH (tested from 4 to 7). Twenty-four lactating cows between 50 and 150 d in milk and averaging about 40 kg of milk/ d were fed a total mixed ration (TMR) consisting of 26% [dry matter (DM) basis] corn silage, 17% alfalfa silage, 7% chopped alfalfa hay, and 50% concentrate. One-half of the cows were fed the TMR without supplementation and the remaining half of the cows were fed the same TMR supplemented with 10 g of the enzyme mixture/ cow per day. After 21 d, the treatments were crossed over for a second 21-d period. The dry enzyme mixture had no effect on DM intake, milk production, or milk composition. Addition of various concentrations of the enzyme mixture did not improve the in vitro digestion of neutral detergent fiber from the TMR. In a digestion trial, lambs were fed a commercial diet supplemented with 4 g of the enzyme mixture/lamb per day, and total feces and urine were collected. Although the ratio of enzyme to feed was much higher than it was in the experiment with lactating cows, addition of the enzyme mixture had no effect on the apparent digestion of DM, acid detergent fiber, neutral detergent fiber, or N in the diet.

Differential and synergistic effects of xylanase and laccase mediator system (LMS) in bleaching of soda and waste pulps

AIMS

Investigation of waste pulps and soda pulp bleaching with xylanase (X) and laccase mediator system (LMS) alone and in conjunction (one after the other) (XLMS).

METHODS AND RESULTS

Soda and different grades of waste pulp fibres [used for making three-layered duplex sheets - top layer (TL), protective layer (PL) and bottom layer (BL)] when pretreated with either xylanase (40.0 IU g(-1)) or LMS (up to 200.0 U g(-1)) alone and in combination (one after the other) (XLMS) exhibited an increase in release of reducing sugars [up to 881.0% soda pulp; up to 736.6% (TL), up to 215.7% (PL) and up to 198.0% (BL) waste pulp], reduction in kappa number [up to 17.6% soda pulp; up to 14.0% (TL), up to 25.3% (PL) and up to 10.9% (BL), waste pulp], improvement in brightness [up to 20.4% soda pulp; up to 23.6% (TL), up to 8.6% (PL) and up to 5.0% (BL), waste pulp] when compared with the respective controls. The usage of XLMS along with 15% reduced level of hypochlorite at CEHHXLMS/EHHXLMS bleaching stage reduced kappa number [5.5% soda pulp; 11.4% (TL), 7.9% (PL), waste pulp] and improved brightness [1.0% soda pulp; 0.9% (TL), 1.4% (PL) waste pulp] when compared with the controls. Scanning electron microscopic studies revealed development of cracks, flakes, pores and peeling off the fibres in the enzyme-treated pulp samples. These modifications of the fibre surface during enzymatic bleaching in turn indicated the removal of lignin and derived compounds from the fibre cell wall.

CONCLUSIONS

The work describes synergistic action of xylanase with LMS for bleaching of waste and nonwood pulps for eco-friendly production of paper and thus reveals a new unexploited arena for enzyme-based pulp bleaching.

SIGNIFICANCE AND IMPACT OF THE STUDY

The drastic improvement in pulp properties obtained after xylanase and LMS treatment would improve the competitiveness of enzyme-based, environmentally benign processes over chemicals both economically and environmentally.

Supplementation of carbohydrases or phytase individually or in combination to diets for weanling and growing-finishing pigs1

The overall objective of the studies reported here was to evaluate the growth and nutrient utilization responses of pigs to dietary supplementation of phytate- or nonstarch polysaccharide-degrading enzymes. In Exp. 1, growth performance and nutrient digestibility responses of forty-eight 10-kg pigs to dietary supplementation of phytase or a cocktail of xylanase, amylase, and protease (XAP) alone or in combination were evaluated. The growth response of one hundred fifty 23-kg pigs to dietary supplementation of phytase or xylanase individually or in combination was studied in Exp. 2 in a 6-wk growth trial, whereas Exp. 3 investigated the nutrient digestibility and nutrient retention responses of thirty 24-kg pigs to dietary supplementation of the same enzymes used in Exp. 2. In Exp. 1, the pigs were used in a 28-d feeding trial. They were blocked by BW and sex and allocated to 6 dietary treatments. The treatments were a positive control (PC) diet; a negative control (NC) diet marginally deficient in P and DE; NC with phytase added at 500 or 1,000 phytase units (FTU)/kg; NC with xylanase at 2,500 units (U)/kg, amylase at 400 U/kg, and protease at 4,000 U/kg; and NC with a combination of phytase added at 500 FTU/kg and XAP as above. In Exp. 2 and 3, the 5 dietary treatments were positive control (PC), negative control (NC), NC plus 500 FTU of phytase/kg, NC plus 4,000 U of xylanase/kg, and NC plus phytase and xylanase. In Exp. 1, low levels of nonphytate P and DE in the NC diet depressed (P < 0.05) ADG of the pigs by 16%, but phytase linearly increased (P < 0.05) ADG by up to 24% compared with NC. The cocktail of XAP alone had no effect on ADG of pigs, but the combination of XAP and phytase increased (P < 0.05) ADG by 17% compared with the NC treatment. There was a linear increase (P < 0.01) in Ca and P digestibility in response to phytase. In Exp. 2, ADG was 7% greater in PC than NC (P < 0.05); there were no effects of enzyme addition on any response. In Exp. 3, addition of phytase alone or in combination with xylanase improved (P < 0.05) P digestibility. Phosphorus excretion was greatest (P < 0.01) in the PC and lowest (P < 0.05) in the diet with the combination of phytase and xylanase. The combination of phytase and xylanase improved P retention (P < 0.01) above the NC diet to a level similar to the PC diet. In conclusion, a combination of phytase and carbohydrases improved ADG in 10-kg but not 23-kg pigs, but was efficient in improving P digestibility in pigs of all ages.

Enhancing In Vitro Degradation of Alfalfa Hay and Corn Silage Using Feed Enzymes

A series of in vitro fermentation experiments was performed to assess the effects of 4 feed enzyme products (FE) that varied in enzymatic activities on the degradation of alfalfa hay and corn silage. The FE contained a range of endoglucanase, exoglucanase, xylanase, and protease activities, and a range of dose rates (DR) was used. The objective of the study was to identify effective formulations and optimum DR, and to establish if combining FE would further improve fiber degradation. For alfalfa hay, quadratic increases in gas production and degradation of dry matter (DM) and fiber were observed for all FE, with maximum responses at low to medium DR. For corn silage, none of the FE increased gas production or DM degradation, but all FE increased NDF degradation, with optimum DR in the low to medium range. The proteolytic enzyme papain improved fiber degradation of alfalfa hay and corn silage in a manner similar to that observed for polysaccharidase FE. Among the polysaccharidase FE, added activities of endoglucanase and exoglucanase were positively correlated with improvement in neutral detergent fiber (NDF) degradability of corn silage, whereas only added endoglucanase activity tended to be correlated with improvement in NDF degradability of alfalfa hay. Combining effective polysaccharidase FE further improved fiber degradation of both forages, with greater improvements for corn silage. Combining polysaccharidase and proteolytic FE further improved NDF degradation of corn silage, but not alfalfa hay. Combination treatments generally resulted in additive effects with increases in fiber degradation equal to the sum of the improvements for the individual enzyme components. Improved fiber degradation of corn silage was associated with decreased acetate to propionate ratios. Enzyme products that improve in vitro degradation of forages may have the potential to improve lactational performance of dairy cows.

Exogenous dietary xylanase ameliorates viscosity-induced anti-nutritional effects in wheat-based diets for White Pekin ducks (Anas platyrinchos domesticus)

Nutrient utilisation and growth performance responses of White Pekin ducks (Anas platyrinchos domesticus) offered diets containing low- or high-viscosity wheat supplemented with xylanase were investigated in two studies. In Expt 1, six diets consisting of low-viscosity wheat or high-viscosity wheat supplemented with 0·0, 1·5 or 3·0 g xylanase (2590 units/g)/kg diet were used in a true metabolisable energy (TME) bioassay with eight 8-week-old ducks per diet group. In Expt 2, eight pens of ten 3-d-old ducks per pen for each of six wheat-based diets arranged in a 2×3 factorial of low-viscosity or high-viscosity wheat and 0·0, 1·5 or 3·0 g xylanase/kg were used in a 42 d growth study. High-viscosity wheat depressed (P>0·001) TME and xylanase supplementation improved (P>0·001) TME, more so for high-viscosity than low-viscosity wheat. Xylanase supplementation of the high-viscosity wheat-based diet improved (P>0·05) weight gain and gain:feed ratio by 13 and 12% respectively. There was no weight gain or gain:feed ratio response to xylanase supplementation of the low-viscosity wheat-based diet. Xylanase supplementation reduced (P>0·001) the viscosity of duodenal and ileal digesta for high-viscosity but not low-viscosity wheat-based diets. Ileal digestibilities of nutrients and energy were higher (P>0·001) for low-viscosity than high-viscosity wheat-based diets; xylanase supplementation improved (P>0·05) energy, fat, N and starch digestibilities. Given that xylanase supplementation of high-viscosity wheat assuaged its anti-nutritional effect, it is surmised that digesta viscosity plays a role in anti-nutritional effects in wheat-based diets for ducks.

Supplementation of Avizyme 1502 to corn-soybean meal-wheat diets fed to turkey tom poults: the first fifty-six days of age

A study was designed to determine the effects of enzyme supplementation on poults fed commercially based diets that included corn, soybean meal, and ground wheat with meat and bone meal (0 to 21 d) or Pro-Pak (22 to 56 d). Day-old turkey poults (n = 3,850) were divided into 35 pens and fed 1 of 5 dietary treatments for 56 d. Treatments were a positive control, a negative control (corn matrix adjustment of 140 kcal), and negative control diets supplemented with Avizyme 1502 at 250, 500, or 750 g/tonne. Feed intake, live weight gain, feed conversion ratio, and mortality were measured for the periods 0 to 21 d, 21 to 42 d, and 42 to 56 d, as well as for the cumulative 0 to 56 d. The 0- to 21-d period was further divided into subperiods (0 to 4 d, 4 to 8 d, 8 to 12 d, 12 to 16 d, 16 to 21 d) to evaluate early nutritional development. Ileal contents along with duodenal, jejunal, and ileal sections (n = 7/treatment) were sampled to determine apparent digestibility and morphology. In most instances, production response differences between the positive and negative controls were not significant, making definitive interpretation of enzyme addition difficult. Energy and protein ileal digestibilities of the negative control diets were lower than those of the positive control diet at 4, 8, 12, 16, and 42 d. Enzyme supplementation significantly improved energy and protein beyond that of the PC diet on d 42. Villus height and crypt depth did not respond to dietary treatment, although there was a significant interaction of age by treatment on jejunal villus height. The similarity between the controls, as well as the high inclusion of CuSO(4), may be responsible for the low response with enzyme inclusion.

On the interactions betweenFusariumtoxin-contaminated wheat and non-starch-polysaccharide hydrolysing enzymes in turkey diets on performance, health and carry-over of deoxynivalenol and zearalenone

1. Diets with increasing proportions of Fusarium toxin-contaminated wheat (0, 170, 340 and 510 g CW/kg) were fed to male turkeys (BUT Big 6) from d 21 to d 56 of age. Each diet was tested with or without a non-starch-polysaccharide (NSP) hydrolysing enzyme preparation. Dietary deoxynivalenol (DON) and zearalenone (ZON) concentrations were successively increased up to approximately 5.4 and 0.04 mg/kg, respectively. 2. Weight gain decreased slightly with increasing proportions of CW, by 1.6, 0.7 and 3.6%, whereas other performance parameters remained unaffected. NSP enzyme supplements to the diets had no influence. 3. The weight of the emptied jejunum plus ileum, relative to live weight, decreased in a dose-related fashion whereby the NSP enzyme exerted an additional weight-decreasing effect. A similar weight-decreasing NSP enzyme effect was noted for heart weights. Activity of glutamate dehydrogenase in serum was significantly increased in groups fed the diets with the highest CW proportion, whereas gamma-glutamyl-transferase remained unaltered. 4. Viscosity in the small intestine was significantly reduced by supplementing the diets with the NSP enzyme. This effect successively decreased with increasing proportions of the CW. 5. Concentrations of DON and of its de-epoxidised metabolite de-epoxy-DON in plasma, liver and breast meat were lower than the detection limits of 2 ng/ml (plasma) and 4 ng/g, respectively, of the applied HPLC method. DON concentration in bile reached up to 13 to 23 ng/ml whereas de-epoxy-DON concentration was lower than 4 ng/ml. 6. ZON or its metabolites were not detectable in plasma, liver or breast meat (detection limits of the HPLC method were 1, 0.5 and 5 ng/g for ZON, alpha-zearalenol (ZOL) and beta-ZOL, respectively). Concentrations of ZON and alpha-ZOL in bile increased with dietary ZON concentration. The mean proportions of ZON, alpha-ZOL and beta-ZOL of the sum of all three metabolites were 19, 77 and 4%, respectively.

The effect of 𝛃-glucanase supplementation of barley- and oat-based diets on growth performance and fermentation in broiler chicken gastrointestinal tract

1. The aim of the present study was to investigate whether grain type (barley or oats) and ss-glucanase inclusion influence the performance and the gastrointestinal ecosystem of broiler chickens, taking the concentrations of short-chain fatty acids and lactic acid, pH, ileal viscosity, and the weight of the caeca and liver into consideration. 2. The inclusion of beta-glucanase in the oat-based diet improved body weight gains. Enzyme supplementation of barley-based diets improved feed conversion efficiency and reduced intestinal viscosity. 3. Irrespective of the type of cereal, beta-glucanase supplementation increased the lactic acid concentration and lowered the pH of the crop contents. No such changes in fermentation were observed in the contents of the gizzard and ileum. 4. Larger amounts of total dietary fibre and its fractions (arabinoxylans and beta-glucans) in oats decreased the weight of the caeca. 5. Molar ratios of acetate, propionate and butyrate in the caecal chyme were affected by cereal type but not by enzyme supplementation. The barley-based diet increased the butyrate:propionate ratio but the opposite effect was observed with the oat-based diet.

[Influence of a xylanase feed additive on Lactobacillus species in the jejunum of piglets]

rRNA extracts from the jejunum of rearing piglets fed a wheat/rye based diet with or without a xylanase feed additive were hybridized against eight Lactobacillus spp. specific digoxigenin labelled oligonucleotide probes. Known concentrations of sample- or culture RNA extracts were used to calibrate and quantify hybridization signals from different sample extracts and hybridizations. The xylanase feed additive tended to increase total eubacterial rRNA in the terminal jejunum, probably a result of increased Lactobacillus spp. rRNA in the central and terminal jejunum. However, individual animal variations were high. L. reuteri was the major Lactobacillus species followed by L. acidophilus and L. mucosae. L. amylophilus and L. crispatus were not detected in all RNA extracts. The results of this study show that the xylanase feed additive modifies Lactobacillus spp. populations on the species level in piglets in addition to their well known effects on digesta viscosity and nutrient digestibility. The implications of these effects for the intestinal microbiota require further analysis.

Prediction of ingredient quality and the effect of a combination of xylanase, amylase, protease and phytase in the diets of broiler chicks. 2. Energy and nutrient utilisation

1. In order to investigate the effects of xylanase, amylase, protease and phytase in the diets of broiler chickens containing graded concentrations of metabolisable energy (ME), two 42-d experiments were conducted using a total of 2208 broiler chicks (8 treatments with 12 replicate pens in each experiment). 2. Four diets including one positive and three negative control diets were used. Three maize/soybean meal-based negative control (NC) diets were formulated to be identical in available phosphorus (P), calcium (Ca) and amino acids but NC1 contained approximately 0.17 MJ/kg less ME than NC2 and approximately 0.34 MJ/kg less ME than NC3. A positive control (PC) was fed for comparison and was formulated to be adequate in all nutrients, providing approximately 0.63 MJ/kg ME, 0.13% available P, 0.12% Ca and 1 to 2% amino acids more than NC1. 3. The reduction in nutrient density between NC1 and PC was determined using ingredient quality models Avichecktrade mark Corn and Phychecktrade mark that can predict the response to exogenous enzymes in maize/soybean meal-based broiler diets. Supplementation of each diet with or without a cocktail of xylanase, amylase, protease and phytase gave a total of 8 dietary treatments in a 4 x 2 factorial arrangement. The same treatments and diet designs were used in both experiments but conducted in different locations using different batches of maize, soybean meal and minor ingredients. 4. In both experiments, digestibility was improved by the addition of exogenous enzymes, particularly those for P, Ca and certain amino acids. In addition, the supplementation of the PC with enzymes elicited a positive response indicating that over-the-top addition of xylanase, amylase, protease and phytase may offer a nutritionally and economically viable alternative to feed cost reduction. 5. It can be concluded that the digestibility of nutrients by broilers fed on maize/soybean meal-based diets can be improved by the use of a combination of xylanase, amylase, protease and phytase.

Prediction of ingredient quality and the effect of a combination of xylanase, amylase, protease and phytase in the diets of broiler chicks. 1. Growth performance and digestible nutrient intake

1. A total of 2208 broiler chicks were used in two growth experiments (8 treatments and 12 replicate pens in each experiment) to assess the effects of xylanase, amylase, protease and phytase in maize-based diets. 2. A positive control diet was formulated containing adequate nutrient concentrations. A negative control diet was formulated to contain approximately 628 kJ/kg, 0.13%, 0.12% and 1 to 2% less metabolisable energy (ME), phosphorus (P), calcium (Ca) and amino acids, respectively, than the positive control. In addition, two further negative control diets that contained 167 or 334 kJ/kg more ME, respectively, than negative control 1 were formulated. 3. A further 4 dietary treatments were made by supplementing each of the 4 negative control diets with a combination of xylanase, amylase, protease and phytase, resulting in 8 dietary treatments in a 4 by 2 factorial arrangement. 4. The scale of the removal of energy, P, Ca and amino acids from the positive control diet was determined using least square models based on in vivo data for both the xylanase/amylase/protease cocktail and for phytase and it was predicted that performance of birds fed on negative control 1 would be returned by supplemental enzymes to that of those fed on the positive control. 5. In both experiments there was a significantly poorer performance in birds fed on the negative control 1 than in those fed on the positive control. The poorer weight gain and feed conversion ratio could be attributed in part to a reduced intake of digestible energy, P, nitrogen (N) and amino acids associated with birds fed on the negative control diet. 6. Supplementation of the negative control diets with the enzyme combination returned performance to that of the positive control in both experiments. 7. These data indicate that exogenous xylanase, amylase, protease and phytase can be used successfully in a strategically formulated low nutrient density diet to maintain performance to that of birds fed on a nutritionally adequate diet.

LePLDbeta1 activation and relocalization in suspension-cultured tomato cells treated with xylanase

Phospholipase D (PLD) has been implicated in various cellular processes including membrane degradation, vesicular trafficking and signal transduction. Previously, we described a PLD gene family in tomato (Lycopersicon esculentum) and showed that expression of one of these genes, LePLDbeta1, was induced by treatment with the fungal elicitor xylanase. To further investigate the function of this PLD, a gene-specific RNAi construct was used to knock down levels of LePLDbeta1 transcript in suspension-cultured tomato cells. Silenced cells exhibited a strong decrease in xylanase-induced PLD activity and responded to xylanase treatment with a disproportionate oxidative burst. Furthermore, LePLDbeta1-silenced cell-suspension cultures were found to have increased polyphenol oxidase activity, to secrete less of the beta-d-xylosidase LeXYL2 and to secrete and express more of the xyloglucan-specific endoglucanase inhibitor protein XEGIP. Using an LePLDbeta1-green fluorescent protein (GFP) fusion protein for confocal laser scanning microscopy-mediated localization studies, untreated cells displayed a cytosolic localization, whereas treatment with xylanase induced relocalization to punctuate structures within the cytosol. Possible functions for PLDbeta in plant-pathogen interactions are discussed.

Influence of supplemental endoglucanase or xylanase on volatile fatty acid production from ruminant feed by ruminal in vitro cultures

This study employed two commercial enzyme preparations to examine the effects of endoglucanase, xylanase or their combination on in vitro volatile fatty acid (VFA) production by ruminal microbial populations. Batch ruminal cultures were established with one of various feedstuffs or with a fescue hay-based diet and ruminal fluid from a heifer fed a 40% forage:60% concentrate diet. Addition of xylanase at 135 xylanase units (XU) per ml increased total VFA production from the fescue hay-based diet (44.3 vs. 57.2 mM, p < 0.05) without changing the acetate to propionate (A:P) ratio. Addition of endoglucanase at 2, 3, 4, and 5 carboxymethyl cellulase units (CMCU) per ml increased total VFA production from the fescue hay-based diet on average by 36% (p < 0.05). Addition of 3, 4 and 5 CMCU/ml also decreased (p < 0.05) the A:P ratio. The combined addition of xylanase (135 XU/ml) and endoglucanase (5 CMCU/ml) increased total VFA production from the fescue hay-based diet (40.9 vs. 61.5 mM, p < 0.05) and reduced the A:P ratio (3.4 vs. 1.5, p < 0.05). The effects of endoglucanase and xylanase supplementation on in vitro VFA production varied across the various substrates used. However, endoglucanase supplementation consistently reduced the A:P ratio with all substrates tested. The effects of the enzyme combination were generally greater than either enzyme alone. We conclude that endoglucanase and xylanase activities differ in their ability to affect ruminal VFA production, and endoglucanase but not xylanase, may improve fermentation efficiency by reducing the A:P ratio.

Carbohydrases, protease, and phytase have an additive beneficial effect in nutritionally marginal diets for broiler chicks

To investigate the additive effects of xylanase, amylase, protease, and phytase in the diets of broiler chickens, a study was conducted using 1,152 growing broiler chicks (8 treatments with 12 replicate pens of 12 chicks). The birds were fed a corn/soybean-based negative control (NC) diet that was formulated to be nutritionally marginal in terms of metabolizable energy, Ca, and P. A nutritionally adequate positive control (PC) diet was fed for comparison. The NC diet was supplemented with phytase; a cocktail of xylanase, amylase, and protease (XAP); or a combination of phytase and XAP at 100 or 200 mg of each enzyme/kg (200 mg of XAP/kg provided a guaranteed minimum of 300 U of xylanase, 400 U of amylase, and 4,000 U of protease/kg; 200 mg of phytase/kg provided a guaranteed minimum of 1,000 U of phytase/kg). Growth performance, ileal digestible energy (IDE), and the digestibility coefficients of N, Ca, P, and DM were calculated. Individually and in combination, both phytase and XAP improved (P < 0.05) gain-to-feed ratio compared with the NC diet, particularly at the highest inclusion concentration. Body weight gain followed a similar trend, showing an improvement of approximately 6 to 7% with either enzyme individually and a 14% improvement with a combination of phytase and XAP. The effect of enzymes on IDE and nutrient digestibility coefficients was not as marked, but a 165 kcal/kg reduction in IDE was noted between the NC and PC diets, and a combination of phytase and XAP improved IDE by >100 kcal/kg. It can be concluded that the use of phytase and XAP individually in a corn/soybean meal-based diet is effective in improving nutrient digestibility and performance of broilers fed nutritionally marginal diets. Furthermore, there may be an additive effect of phytase and XAP on broiler performance, giving a cost-effective nutritional strategy for the profitable production of poultry products.

Elicitor-induced activation of transcription via W box-related cis-acting elements from a basic chitinase gene by WRKY transcription factors in tobacco

A putative elicitor responsive element with two W boxes (CTGACC/T) has been identified in the region between -125 and -69 of a tobacco class I basic chitinase gene CHN48. We generated transgenic tobacco calli that contained the -125/-69 region fused to a luciferase reporter gene. The expression of the reporter gene was induced upon treatment with an elicitor, xylanase from Trichoderma viride (TvX). This induction required protein kinase activity. We isolated three cDNA clones encoding DNA-binding proteins, designated as NtWRKY1, NtWRKY2, and NtWRKY4, from tobacco cultured cells. Gel mobility shift assays showed that in vitro translation products of NtWRKY1, NtWRKY2 and NtWRKY4 bound to W box of CHN48 gene. These NtWRKY proteins stimulated W box-mediated transcription of a luciferase reporter gene in the transient assay. In addition, the transactivation of W box-mediated transcription by NtWRKY1 and NtWRKY4 was enhanced in response to elicitor treatment, suggesting elicitor-induced posttranscriptional activation of these NtWRKYs. Northern blot analyses showed that mRNAs for NtWRKY1 and NtWRKY2 increased after treatment with the elicitor, whereas mRNAs for NtWRKY4 were expressed constitutively at a low level. These results suggested possible involvement of NtWRKYs in elicitor-responsive transcription of defense genes in tobacco.

Influence of phytase and xylanase, individually or in combination, on performance, apparent metabolisable energy, digestive tract measurements and gut morphology in broilers fed wheat-based diets containing adequate level of phosphorus

1. The aim of the present study was to examine the influence of microbial phytase and xylanase, individually or in combination, on performance, apparent metabolisable energy, digesta viscosity, digestive tract measurements and gut morphology in broilers fed on wheat-soy diets containing adequate phosphorus (P). The wheat-soy basal diet was formulated to contain 4.5 g/kg non-phytate P and the experimental diets were formulated by supplementing the basal diet with xylanase (1000 xylanase units/kg diet), phytase (500 phytase units/kg diet) or a combination of phytase and xylanase. 2. Supplemental phytase improved the weight gains and feed efficiency by 17.5 and 2.9%, respectively. Corresponding improvements due to the addition of xylanase were 16.5 and 4.9%, respectively. The combination of phytase and xylanase caused no further improvements in broiler performance. 3. Individual additions of xylanase or phytase resulted in numerical improvements in apparent metabolisable energy (AME), but the differences were not significant. The combination of the two enzymes significantly increased AME. Addition of xylanase and the combination of the two enzymes reduced the viscosity of digesta in all sections of the intestine. Phytase supplementation reduced digesta viscosity in the duodenum and ileum, but not in the jejunum. 4. Enzyme supplementation lowered the relative weight and length of the small intestine. Additions of xylanase and phytase reduced the relative weight of the small intestine by 15.5 and 11.4%, respectively, while the corresponding reductions in the relative length of the small intestine were 16.5 and 14.1%, respectively. The combination of phytase and xylanase had no further effects on the relative weight and length of the small intestine compared with the xylanase group. 5. The addition of phytase increased villus height in the duodenum and decreased the number of goblet cells in the jejunum compared with those on the unsupplemented basal diet. Xylanase supplementation tended to increase goblet cell numbers in the duodenum and decreased crypt depth in thejejunum. The combination of phytase and xylanase increased villus height in the ileum and crypt depth in thejejunum and ileum. 6. In summary, the present results showed that the addition of a microbial phytase, produced by solid state fermentation and containing significant activities of beta-glucanase and xylanase, was as effective as xylanase in improving the performance of broiler chickens fed on wheat-based diets containing adequate levels of P. Improved performance with enzyme supplementation was generally associated with reduced digesta viscosity, increased AME, and reduced relative weight and length of small intestine.

Effect of enzyme addition to wheat-, barley- and rye-based diets on nutrient digestibility and performance of laying hens

1. Laying hen performance, egg quality, intestinal viscosity and nutrient apparent digestibility were evaluated with respect to the main cereal used in the diet and dosage rate of a fungal beta-glucanase/xylanase enzyme complex. 2. Twelve diets were arranged factorially, with three soluble fibre cereals (SFC); 500 g/kg of wheat or barley or 350 g/kg of rye, and 4 enzyme concentrations (0, 250, 1250 and 2500 mg/kg). An additional control diet based on maize was also included. 3. The use of SFC in the diet instead of maize did not affect egg production or food efficiency, but hens fed on SFC diets exhibited a higher incidence of dirty eggs than hens fed on the maize diet (8-6 vs 4.6%; P<0.01). 4. Laying hens fed on enzyme-supplemented diets produced more eggs (2.1%; P<0.05) and had better food efficiency per dozen eggs (2.5%; P<005) than hens fed on non-supplemented diets. An excess of enzymes in the diet (10 times the recommended dose) did not produce any deleterious effect on laying hen productivity. 5. Enzyme supplementation (ES) reduced intestinal viscosity (P<0.001) and the incidence of dirty eggs (P<0.01). The reduction in viscosity was more pronounced in barley than in wheat or rye diets (P<0.05). 6. Apparent nutrient digestibility in SFC diets was higher with ES, including dry matter (3.1%; P=0.08), fat (4.4%; P<0.001), non-starch polysaccharides (83.3%; P<0.01) and AMEn (2.5%, P<0.01). 7. It is concluded that substitution of maize by SFC is facilitated by ES, especially with respect to egg production, food conversion efficiency and egg shell cleanliness. An excess of enzymes did not produce any deleterious effect on nutrient digestibility or performance of laying hens.

Effect of xylanase and beta-glucanase supplementation of wheat- or wheat- and barley-based diets on the performance of male turkeys

The efficiency of a mixture of xylanase and beta-glucanase enzymes was evaluated in two separate experiments on growing turkeys offered diets based on wheat or wheat and barley. 2. In the first experiment, the addition of 560 and 2800 IU of xylanase and beta-glucanase, respectively, per kg of diet significantly improved feed efficiency in turkeys fed on wheat- and barley-based diet throughout the entire experiment (42 d). 3. In the second experiment, the enzyme mixture significantly increased N-corrected apparent metabolisable energy (AMEN) by approximately 5%. 4. Furthermore, the combination of xylanase and beta-glucanase significantly improved body weight gain and feed efficiency. Feed efficiency was increased by 2.94, 2.47 and 5.91% in diets based on 500 then 540 g of wheat/kg of diet, 394 then 384 g of wheat and 100 then 150 g of barley/kg of diet and 180 g of wheat and 300 then 350 g of barley/kg of diet, respectively. 5. This enzyme mixture decreased in vitro viscosity of wheat, barley and soybean meal, the effect being larger for wheat and barley than for soybean meal. 6. In conclusion, the supplementation of diets based on wheat and barley with xylanase and beta-glucanase significantly improved body weight gain and feed efficiency. Therefore, wheat and barley could be used more efficiently by turkeys in the presence of an appropriate enzyme preparation.

Effect of a bacterial xylanase and/or antibiotic growth promoter on zootechnical performances of piglets fed arabinoxylan rich diets

272 cross bred piglets (Saw (wbp x pbz) x Boar (Hamp x Pietr) were fed a basal diet rich in arabinoxylans from 29 days old to 84 days old. In the prestarter period (29 to 42 d) the basal diet was formulated with 27% wheat, 10% barley, 10% maize, 18% soybean meal and 22% milk products and the analytical content was adjusted at 13.81 MJ/kg metabolisable energy, 19.6% crude protein, 12.4% lactose, 1.38% lysine and 0.88% SAA. During the starter period (43 to 84 d) the basal diet was formulated with 53% wheat, 25% barley and 16% soybean meal and the analytical content was adjusted at 12.91 MJ/kg metabolisable energy, 16.7% crude protein, 1.09% lysine, 0.62% SAA.