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1.
ABSTRACT

1. This study quantified xylanase-induced changes in soluble monosaccharides, xylooligosaccharides (XOS) and volatile fatty acid (VFA) contents of the different sections of the gastrointestinal tract (GIT) and whether these were related to altered bird performance.

2. An in vitro digestion of the wheat-based diet was carried out with the xylanase (Econase XT at 16,000BXU/kg diet) to compare the in vitro and in vivo generation of these XOS and monosaccharides. For the in vivo study, 80 male Ross 508 b roiler chicks were split into two groups fed a wheat-based diet with or without Econase XT (16,000BXU/kg diet) for 21 days.

3. There were no effects of Econase XT inclusion on growth performance characteristics, likely a result of the high-quality wheat diet, the corresponding high performance of the control group (FCR average of 1.45 in controls) and the relatively young age of the birds (from four to 26 days of age).

4. Econase XT supplementation increased the xylotetraose (X4) content in the colon (P = 0.046, enzyme x GIT section interaction) and the xylose contents in the colon and caeca (P < 0.001, enzyme x GIT section interaction).

5. The trend for increased acetate production in the caeca of Econase XT treated birds (P = 0.062) suggested that the XOS generated were subsequently fermented in the caeca, potentially impacting upon the types of microbiota present.

6. The present study suggested that wheat arabinoxylan degradation was enhanced by xylanase supplementation, which may have increased the production of beneficial volatile fatty acids (VFA) in the caeca, and thereby potentially modulated the caecal microbiome, but without affecting bird performance at this early age.  相似文献   

2.
ABSTRACT

1. The present study examined the potential of new-generation microbial enzymes to improve the utilisation of energy and protein of cottonseed meal (CSM)-containing diets, with the aim of increasing its inclusion level in broiler chickens diets.

2. Four hundred and eighty, one-day-old Ross 308 male broilers were used to assess the utilisation of energy and protein by broiler chickens fed diets containing four graded levels of CSM – none, low (4, 8, 12%), medium (5, 10, 15%) or high (6, 12, 18%) in the starter, grower, and finisher phases, respectively, supplemented with 100 mg/kg of a composite enzyme product (xylanase and β-glucanase).

3. Inclusion of CSM improved (P < 0.01) apparent metabolisable energy (AME), with further improvement (P < 0.001) seen in the enzyme-supplemented diets. Inclusion of CSM reduced (P = 0.002) the metabolisable energy intake (MEI), but this was increased (P < 0.05) with enzyme supplementation.

4. Enzyme addition increased (P < 0.001) the net energy of production (NEp), while heat production (HP) decreased (P < 0.001) with CSM inclusion. More energy was retained as fat (P < 0.05) and protein in birds fed diets with the enzyme, but this was reduced (P < 0.029) by CSM.

5. There was an increase (P < 0.05) in efficiencies of ME use for energy, lipid and protein retention, with higher CSM levels. The enzyme improved (P < 0.013) efficiency of ME use for lipid retention.

6. Feeding diets containing CSM to the broilers enhanced (P < 0.05) protein intake (PI) and protein efficiency ratio (PER). Positive effects (P < 0.05) of enzyme were observed on protein gain (PG) and net protein utilisation (NPU).

7. Results obtained from this study suggested that nutrient utilisation of diets containing CSM by broiler chickens can be improved by enzyme supplementation.  相似文献   

3.
ABSTRACT

1. Two separate experiments were conducted to evaluate the efficacy of either prebiotic or synbiotic on growth performance, carcass yield, organ weights, and serum metabolic profile of broilers under hot climatic conditions.

2. In experiment 1, 150 1-d-old Ross 308 male broiler chickens were fed dietary synbiotic (Biomin® IMBO, 0, 1 or 1.5 g kg?1 of the starter diets and 0, 0.5 or 0.75 g kg?1 of the grower diets) for 6 weeks. In experiment 2, 150 1-d-old Ross 308 male broiler chickens were fed dietary prebiotic (Mannan oligosaccharide 0, 0.5 or 1 g kg?1 of the starter diets and 0, 0.25 or 0.5 g kg?1 of the grower diets) for 6 weeks. Each treatment had 10 replicates containing 5 broiler chickens each.

3. Supplementation of synbiotic at 1 or 1.5 g kg?1 feed to broiler diets during 1–21 d and 0.5 or 0.75 g kg?1 feed, respectively, during 22–42 d improved (P < 0.01) body weight gain, feed conversion ratio (FCR), and decreased (P < 0.01) abdominal fat, serum total cholesterol, and low-density lipoprotein (LDL) cholesterol levels in experiment 1.

4. Similarly, supplementation of the prebiotic at 0.5 or 1 g kg?1 in broiler diets during 1–21 d and 0.25 or 0.50 g kg?1 feed, respectively, during 22–42 d improved (P < 0.01) body weight gain, FCR, and decreased (P < 0.01) abdominal fat, serum cholesterol, and LDL-cholesterol levels in experiment 2.  相似文献   

4.
ABSTRACT

1. The aim of this trial was to determine the optimal supplementation level of a xylanase enzyme from Trichoderma citrinoviride on growth performance, apparent ileal and total tract nutrient retention, intestinal morphology, and intestinal concentration of volatile fatty acids in broiler chickens.

2. A total of 600 broiler chickens (Ross 308) of mixed sex were randomly allotted to four treatments, on the basis of similar body weight. The dietary treatments were made from a corn-wheat-soy based diet supplemented with either 0, 3750, 7500, or 11 250 XU/kg xylanase and were fed to 32 d of age.

3. A linear response to increasing dietary xylanase was demonstrated for overall weight gain (P < 0.05) and feed conversion ratio (P < 0.05). The apparent total tract digestibility of dry matter and gross energy, and the coefficient of apparent ileal digestibility (CIAD) of N and soluble non-starch polysaccharides were linearly improved when xylanase was added to the diet (P < 0.05). Moreover, a linear increase (P < 0.05) was observed in the CIAD of Arg, Lys, and Try with increasing dietary levels of xylanase.

4. The viscosity of digesta in ileum was linearly decreased when dietary xylanase level increased (P < 0.05).

5. An increase in villus height of the duodenum and jejunum were observed with increasing dietary levels of xylanase (linear, P < 0.05).

6. Overall, the results showed that the effects of dietary xylanase supplementation on broiler performance was determined through effects on nutrient availability and intestinal morphology.  相似文献   

5.
ABSTRACT

1. The effects of supplementation of broiler chicken diets with pea meal, carbohydrase enzymes and a probiotic were investigated for potential performance improvement.

2. Raw or extruded pea meal (cv Model, grown in Poland) was included in a wheat-soybean meal-based diet at 250 g/kg. The diets were unsupplemented (control) or supplemented with either carbohydrase enzymes (200 U/kg xylanase and 10 U/kg β-glucanase in feed) or a probiotic (Bacillus subtilis), or both. The diets were fed to Ross 308 broilers aged 9–28 days.

3. After two additional days, chick gastrointestinal tracts were excised and analysed for the presence of Bacillus subtilis biofilm; and the ileal and caecal digesta were analysed for bacterial enzyme activities and to determine the concentration of short-chain fatty acids (SCFAs).

4. Feeding the pea-based diet supplemented with the probiotic compromised feed utilisation, due to higher feed intake. The addition of enzymes to the raw, but not the extruded, pea containing diet partially ameliorated this effect (pea form × additives; P < 0.002).

5. In the ileal digesta, interactions between the dietary treatments were observed for the activities of all bacterial glycolytic enzymes and for SCFA concentrations. β-glucosidase, α-galactosidase and β-glucuronidase were highest in birds fed the diet containing extruded pea supplemented with the probiotic and enzymes (pea form x additives; P = 0.018 to P < 0.006). In the caecal digesta, interactions were observed for bacterial enzyme activities, but not for total SCFA concentration. Biofilm formation in the caecum indicated that the probiotic strain was metabolically active in the broiler gut.

6. In conclusion, supplementation of diets containing raw or extruded pea meal with enzymes and a Bacillus subtilis spore-based probiotic modulated microbiota activity but had no clear effects on broiler performance. Probiotic administration did not cause excessive fermentation in the ileum and caecum but enhanced Bacillus subtilis spp. biofilm formation in the caecum, which may be indicative of a beneficial effect on gut health.  相似文献   

6.
ABSTRACT

1. This study was conducted to determine the effect of different sources of selenium (Se) on breast and liver tissue deposition, apparent metabolisable energy (AME), growth performance and antioxidant status of broilers, measured as Se content in liver and breast tissues and glutathione peroxidase (GSH-Px) in blood, when used in 0–35 d broiler chicken diets.

2. A total of 200 male Ross 308 broilers were used in the feeding trial, which comprised two dietary phases, a starter from 0 to 21 d and finisher from 21 to 35 d of age. Four treatments with 10 replications each were used. A control diet (C) was formulated that was sufficient in protein and energy (230 and 215 g/kg of crude protein and 12.67 and 13.11 MJ/kg of metabolisable energy, respectively), for both phases, but contained background Se only from the feed ingredients. Diet 2 (IS) was supplemented with 10.35 g/t inorganic, elemental source of Se. Diet 3 (SY) was supplemented with 136.36 g/t selenised yeast, an organic source derived from Saccharomyces cerevisiae. Diet 4 (SS) was supplemented with 0.666 g/t sodium selenite, an inorganic source.

3. Birds fed the SY diet consumed less and weighed less than those fed IS or C (P < 0.05; 0–35 d of age), but there was no difference compared to birds fed SS diets. There were no differences in FCR or dietary AME between broilers fed different Se sources. All diets containing supplementary Se increased concentrations in the liver and breast muscle, and for GSH-Px levels in blood compared to birds fed the C diet (P < 0.001). Birds fed SY diets had greater Se levels in liver and breast tissues compared to birds fed any of the other diets (P < 0.001).

4. Diets supplemented with Se had variable effects on broiler growth performances and antioxidant status. Feeding Se from a yeast source has higher transfer into breast tissues. Feeding different sources and levels of Se to birds in a more challenging situation to induce oxidative stress may bring more conclusive results.  相似文献   

7.
ABSTRACT

1. A 21-d experiment was conducted to investigate the effect of graded inclusions of waxy starch hull-less (WSHL) barley and a multi-component exogenous carbohydrase on the growth performance, nutrient digestibility and intestinal morphometry of broiler chickens. Five levels of WSHL barley inclusion (0, 65, 130, 195 and 260 g/kg) in a wheat-based diet, and two levels of enzyme supplementation (0 and 150 g/tonne of feed) were evaluated in a 5 × 2 factorial arrangement of 10 dietary treatments. All diets were equivalent in metabolisable energy and digestible amino acid content. A total of 400, one-d-old male broilers (five cages/treatment; eight birds/cage) were used in the experiment.

2. Regardless of enzyme supplementation, feed intake declined (P < 0.001) with increasing inclusion of WSHL barley. Increasing levels of WSHL barley (P < 0.001) and supplemental enzyme (P < 0.01) increased gain to feed ratio.

3. Birds fed diets with 0 g/kg WSHL barley showed the lowest (P < 0.001 to 0.01) digestibility for all nutrients except starch. Only starch digestibility was improved (P < 0.05) by enzyme supplementation. The nitrogen-corrected apparent metabolisable energy improved with increasing inclusion of WSHL barley (P < 0.001) and supplemental enzyme (P < 0.001). Increasing inclusion of WSHL barley increased the relative weight of gizzard (P < 0.001) and reduced jejunal digesta viscosity (P < 0.01). Supplemental enzyme (P < 0.001) reduced digesta viscosity.

4. All levels of WSHL barley inclusion improved digestibility of dry matter, nitrogen and fat, whilst energy utilisation improved at inclusions of 130 g/kg WSHL and above, probably due to lowered digesta viscosity and better development of the gizzard. Gain to feed ratio, starch digestibility, energy utilisation and jejunal digesta viscosity can benefit from carbohydrase supplementation in wheat-based diets, regardless of barley inclusion level.  相似文献   

8.
ABSTRACT

1. This study was conducted to assess the effects of graded levels of dietary corn resistant starch (RS) on growth performance, carcass traits, nutrient retention, digestive organ index, intestinal morphology, digestive enzyme activities, and mRNA expression of certain nutrient transporters in broiler chickens.

2. A total of 320, 1-d-old Arbor Acres broiler chickens were randomly assigned to five dietary treatments, with eight replicates of eight birds in each. These treatments included one corn-soybean control diet, a corn-soybean based diet containing 20% corn starch, and three diets supplemented with 4%, 8% and 12% RS by replacing corn starch with 6.67%, 13.33% and 20% of Hi-Maize 260® (identified as control, RS1, RS2, RS3 and RS4, respectively). The feeding period lasted 42 days.

3. Performance parameters including feed consumption, feed conversion, body weight gain and percentage of abdominal fat at d 42 of age, nutrient retention (including dry matter, fat, total starch and nitrogen free extract), and apparent metabolisable energy was measured from d 18 to 20 and d 39 to 41 and showed negative linear responses to increasing dietary RS level (P < 0.05). Birds fed the RS3 and RS4 diets showed higher relative weight of duodenum, jejunum and ileum, as well as lower villus height and villus height/crypt depth compared to the control (P < 0.05). The activity of pancreatic trypsin of birds at d 21 and 42 of age decreased linearly in response to the increase of dietary RS level (P < 0.01). There were linear changes in up-regulated mRNA expression of SGLT-1 and down-regulated mRNA expression of GLUT-2 with increasing proportion of RS at d 21 and 42 of age (P < 0.05), respectively.

4. It was concluded that feeding broilers with diets containing higher concentrations of RS impaired the development of small intestine, which resulted in lower apparent total tract retention of nutrients and poorer body weight gain, feed efficiency and carcass traits of broiler chickens.  相似文献   

9.
ABSTRACT

1. This feeding trial investigated the effects of herbal feed additives on performance of broiler chickens, jejunal and caecal microbiota, jejunal morphology, meat chemical composition and oxidative stability during refrigerated storage.

2. In a 42 days trial, 320 one-day-old broiler chickens were randomly allocated to 4 groups with 4 replicate pens each containing 20 chicks. The control group was fed maize–soybean-based diets. The diets of the other three groups were supplemented with herbal feed additives: HRB1 with StresomixTM (0.5 g/kg feed); HRB2 with AyuceeTM (1.0 g/kg feed); HRB3 with Salcochek ProTM (1.0 g/kg feed). The GC/MS analysis of the feed additives showed that the major components of HRB1 were β-caryophyllene (14.4%) and menthol (9.8%); HRB2 were n-hexadecanoic acid (14.22%) and β-caryophyllene (14.4%); and HRB3 were menthol (69.6%) and clavicol methyl ether (13.9%).

3. Intestinal samples were taken at 42 day to determine bacterial populations (total aerobe counts, Lactobacilli, and Escherichia coli) and perform gut morphology analysis. Meat samples were analysed for chemical composition and oxidative stability under storage.

4. The HRB1 group had improved (P < 0.05) body weight gain and tended to have improved (0.05 ≤ P < 0.10) feed conversion ratio, compared to the control group. Jejunum lactic acid bacteria counts were increased (P < 0.001) in groups HRB1 and HRB3, compared to the control group, whereas caecal lactic acid bacteria counts tended to increase (0.05 ≤ P < 0.10) in group HRB1, compared to the control group. Breast meat fat content tended to be lower (0.05 ≤ P < 0.10) in group HRB1. Meat oxidative stability was improved (P < 0.001), and jejunum villus height, crypt depth and goblet cells numbers were increased (P < 0.001) in all three herbal supplemented groups, compared to the control.

5. In conclusion, herbal feed additives may be able to improve both growth performance and antioxidant activity of broiler chickens, based on their phenolic compound content.  相似文献   

10.
ABSTRACT

1. Two consecutive trials were conducted to evaluate the effects of guanidinoacetic acid (GAA) supplementation (a creatine precursor) and energy levels in broiler diets based on maize-soybean meal (Trial 1) or that additionally included poultry by-product meal (PBPM; Trial 2) on growth performance, carcass yield and breast meat quality to 41 days of age.

2. A total of 792, one-day-old male Ross 308 broiler chickens were randomly distributed into six treatments – three energy levels (sufficient AMEn or 0.2 and 0.4 MJ/kg reduced AMEn) and two GAA levels (0.00% or 0.06%) with eight replicates for each trial.

3. Reducing dietary energy resulted in poorer body weight gain (BWG) and feed conversion ratios (FCR) for each trial (P < 0.05). However, GAA supplementation improved FCR, BWG and European Production Efficiency Factor (EPEF) (P < 0.05).

4. Dietary energy level and GAA addition had no significant effect on carcass parameters, drip loss, pH and chemical composition of breast meat (P > 0.05), but decreased relative liver weight (P < 0.05).

5. It was concluded that, regardless of dietary energy levels, supplementation of GAA to plant-based diets or those including PBPM has the potential to improve growth performance in broilers.  相似文献   

11.
1. This study investigated the prebiotic properties of arabinoxylo-oligosaccharides (AXOS) produced both in situ and in vitro for their activity against the onset of necrotic enteritis in broiler chickens.

2. A 2 × 3 factorial arrangement was applied, including necrotic enteritis challenge (challenged/unchallenged) and three dietary treatments from d 10 to 21. A wheat–soy commercial-type basal-grower diet was fed with 2% of the wheat proportion replaced by the same amount of either arabinoxylan (AX), AXOS produced from hydrolysing AX with 16 000 BXU (birch xylanase unit) xylanase in vitro or AX fed with 16 000 BXU xylanase (AX + E). Necrotic enteritis (NE) challenge was induced by orally infecting birds with a vaccine strain of Eimeria oocysts at d 9 of age followed by oral gavage of a freshly prepared Clostridium perfringens broth at d 14.

3. The challenge depressed growth performance, induced gross lesions and reduced ileal viscosity at d 10–21. Birds fed on the AXOS diet had numerically less severe gross lesions, improved feed conversion at d 0–16 and lower ileal viscosity at d 16 compared to birds fed on AX. Weight gain of the unchallenged birds ranked as follows in terms of the diets: AXOS > AX + E > AX. AX + E produced a lower ileal viscosity compared to the AX treatment but only led to marginal improvements in performance and intestinal lesion scores.

4. Caecal short-chain fatty acid (SCFA) concentration was higher in birds fed on AXOS and AX + E compared to those fed on AX and was higher in the challenged birds compared to the unchallenged birds. Gizzard pH was lower in birds fed on AX + E compared to those fed on AXOS at d 16. Challenged birds had lower ileum pH compared to the unchallenged birds at d 16 and 21.

5. Results of this study suggest that AXOS appeared to be efficacious prebiotics, as highlighted by improvements in feed conversion ratio and increased SCFA production. Future studies are warranted to elucidate the types of AXOS that are most active against NE and the mechanisms by which different levels of AXOS enhance bird performance.  相似文献   


12.
1. The current study was conducted to investigate the effect of high phytase doses on growth performance and real-time gastric pH measurements in broiler chickens and pigs.

2. In the first experiment, 576 male Ross 308 broilers were fed in two phases (0–21 and 21–42 d) with 4 treatment groups, with diets meeting nutrient requirements containing 0, 500, 1500 or 2500 FTU/kg phytase. In the second, 64 Landrace weaners were fed on diets meeting nutrient requirements with or without phytase (0 or 2500 FTU/kg) in two phases (0–21 and 21–42 d). Heidelberg pH capsules were administered to 7 broilers and approximately 13 pigs per treatment group, pre- and post-phase change, with readings monitored over several hours.

3. Addition of phytase into an adequate Ca and P diet had no significant effect on broiler performance although phytase tended (P < 0.07) to improve feed conversion in pigs over the entire experimental period. Real-time pH capsule readings in broilers demonstrated an increase (P < 0.05) in gizzard pH when phytase was dosed at 500 or 1500 FTU/kg, while higher doses of 2500 FTU/kg phytase lowered pH to a level comparable to control birds. Gastric pH increased (P < 0.01) when animals were exposed to dietary phase change, signifying a potential challenge period for nutrient digestibility. However, pigs fed 2500 FTU/kg were able to maintain gastric pH levels through diet phase change. In contrast, spear-tip probe measurements showed no treatment effect on gastric pH.

4. These findings demonstrate dietary manipulation of gastric pH and the value of real-time pH capsule technology as a means of determining phytase dose response.  相似文献   

13.
ABSTRACT

1. Chicken-associated Campylobacter spp. are the cause of most food poisoning cases in Europe. In order to study the host–pathogen interactions, a reliable and reproducible method of colonising chickens with the bacteria is required.

2. This study aimed to identify a more appropriate and less invasive method of colonisation (cf. gavaging) by seeding bedding material (litter) that commercial chickens are kept on with a mixture of Campylobacter spp., broth and faeces.

3. The first phase of the study tested the longevity of Campylobacter spp. recovery in seeded litter over 24 h: significantly more Campylobacter spp. was recovered at 0 or 3 h post-seeding than at 6 and 24 h post-seeding, indicating that the pathogen can survive to detectable levels for at least 3 h in this environment.

4. In the second phase, three groups of 10 broiler chickens (negative for Campylobacter spp. prior to exposure) were exposed at 21 days of age to one of three different Campylobacter jejuni and C. coli mixes (A, B, C), using the method above. At 28 days of age, birds were euthanised by overdose of barbiturate or cervical dislocation, and livers and caeca removed for Campylobacter spp. assessment.

5. All liver and 28/30 caeca samples tested positive for Campylobacter spp., with mix A and C giving higher counts in the caeca than mix B. The method of euthanasia did not affect Campylobacter spp. counts.

6. In conclusion, a successful method for reliably colonising broiler chickens with Campylobacter spp. has been developed which negates the need for gavaging and is more representative of how contamination occurs in the field.  相似文献   

14.
1. The aim was to investigate the effect of grain type (barley or rye) and exogenous enzymes (β-glucanase or xylanase) on the composition of chicken caecal microbiota as examined by classical culturing and molecular techniques (fluorescent in-situ hybridisation (FISH) and terminal-restriction fragment-length polymorphism (T-RFLP)). 2. Plate counting revealed higher total numbers of anaerobic bacteria, lactic acid bacteria and yeasts in caecal contents of birds fed with rye-based diets than in birds fed with barley-based diets. 3. As assessed by FISH analysis, the most abundant bacterial groups in the broiler caeca were Clostridium coccoides-Eubacterium rectale followed by Bacteroides sp., Lactobacillus sp./Enterococcus sp., Bifidobacterium sp. and Enterobacteriaceae. For both cereal types, the enzyme supplementation significantly decreased the relative amount of Enterobacteriaceae. 4. The T-RFLP profiles indicated that the caecal microbiota of birds receiving rye-based diets was more diverse than that of birds fed on barley-based diets. 5. Irrespective of the method applied, the results indicate that the cereal type as well as the exogenous enzyme supplementation influence the microbiota in broiler chicken caeca, and may have the effect of reducing potentially pathogenic Enterobacteriaceae populations.  相似文献   

15.
木聚糖酶对肉仔鸡后肠道微生物的影响   总被引：4，自引：0，他引：4  
主要研究了小麦基础口粮添加木聚糖酶对肉仔鸡后肠道微生物的影响.将120只7日龄肉仔鸡分成2组,日粮分别添加0,0.1%木聚糖酶,饲喂至21日龄,研究木聚糖酶对肉仔鸡后肠道菌群数量变化的影响.结果表明,加酶未使同肠和盲肠乳酸杆菌、双歧杆菌和大肠杆菌数量发生显著变化.利用变性梯度凝胶电泳技术研究了木聚糖酶对肉仔鸡后肠细菌群体的影响.结果表明,加酶组回肠和盲肠的图谱比对照组条带相对较多,但差异不显著;组内个体间的图谱相似性比组问的相似性相对较大.木聚糖酶影响肉仔鸡后肠微生物数量和种群的作用效果不明显.  相似文献   

16.
1. Five dietary treatments were used in a 49 d broiler trial to assess the effect of xylanase on performance, nutrient digestibility and thermal profiles of the caeca and head. Treatments included an industry-standard control diet and four further diets where xylanase was introduced with or without a metabolisable energy density dilution either from day one or the introduction was delayed until d 28.

2. The addition of xylanase with no associated energy dilution from day one resulted in the most consistent beneficial effects on performance, with significant improvements in weight gain compared with the industry-standard to d 28 and at d 49. Addition of xylanase from d 28 (with no energy dilution) was the second most successful strategy and resulted in a significant improvement in feed conversion ratio (FCR) from d 29 to 49 and overall.

3. Addition of xylanase improved ileal digestible energy values at d 28 by around 0.35 MJ/kg and ileal nitrogen digestibility coefficients by around 3%. On d 49 xylanase improved ileal digestible energy values by around 0.9 MJ/kg and ileal nitrogen digestibility coefficients by around 4.6%.

4. Thermal imaging of the head and caeca of three birds per replicate on d 49 revealed a significant increase in caecal surface temperature following xylanase addition with no effect on head temperature profile. These increases were particularly large (around 1.4ºC, or 3.9%) when xylanase was added from day one with no corresponding energy dilution in feed formulation.

5. It can be concluded that supplemental xylanase is effective in improving performance and nutrient digestibility in broilers given wheat-based diets. The correlation between the magnitude of this effect and the increased temperature in the caeca presents additional evidence that the hind-gut microflora may play an important, if yet unquantified, role in the outworking of these mechanisms.  相似文献   


17.
ABSTRACT

1. The current study was conducted to evaluate the influence of high phytase doses and xylanase, individually and in combination, on performance, blood inositol and real-time gastric pH in broilers fed wheat-based diets.

2. In a 42-d experiment, a total of 576 male Ross 308 broiler chicks were allocated to 4 dietary treatments. Treatments consisted of a 2 × 2 factorial arrangement, with 500 or 2500 FTU/kg phytase and 0 or 16 000 BXU/kg xylanase, fed in two phases (starter 0–21; grower 21–42 d). Heidelberg pH capsules were administered to 8 birds from each treatment group, pre- and post-diet phase change, with readings captured over a 5.5-h period.

3. At 21 and 42 d, birds fed 500 FTU/kg phytase without xylanase had on average 127 and 223 g lower weight gain than all other treatments, respectively (P < 0.05). At 42 d, body weight-corrected feed conversion ratio (bwcFCR) was reduced (P < 0.05) by supplementing 2500 FTU/kg phytase or xylanase, with the combination giving a 12 point reduction in bwcFCR compared to birds fed 500 FTU/kg phytase without xylanase. Inositol content of plasma was twice that of the erythrocyte (P < 0.001), with 2500 FTU/kg phytase tending to increase (P = 0.07) inositol content in both blood fractions.

4. Across all treatments, capsule readings ranged from pH 0.54 to 4.84 in the gizzard of broilers. Addition of 2500 FTU/kg phytase to the grower diet reduced (P < 0.05) average gizzard pH from 2.89 to 1.69, whilst feeding xylanase increased (P < 0.001) gizzard pH from 2.04 to 2.40. In contrast, digital probe measurements showed no effect of xylanase on gizzard pH, while addition of 2500 FTU/kg phytase increased (P = 0.05) pH compared to 500 FTU/kg phytase with or without xylanase.

5. These findings suggested that xylanase and high phytase doses have opposite effects on real-time gastric pH, while similarly improving performance of broilers.  相似文献   

18.
1. The effects of 3 commercial enzyme products on the nutritive value of 2 lupin species were investigated with the emphasis on changes in composition of non-starch polysaccharides (NSPs) along the digestive tract. Enzyme A contained primarily cellulase, beta-glucanase and xylanase activities, enzyme B primarily hemicellulase, pentosanase and xylanase activities, and enzyme C primarily hemicellulase, pectinase and beta-glucanase activities. 2. The enzymes were added to semi-purified diets based on sorghum and casein containing 35% whole seed lupins (Lupinus angustifolius cv Gungurru or Lupinus albus cv Kiev mutant). Control diets contained no lupins. 3. Food conversion ratio (FCR), excreta moisture content and apparent metabolisable energy (AME) were affected by lupin species but not by enzyme supplementation. 4. In diets with L. angustifolius, enzyme C significantly increased digesta viscosity and increased the concentration of soluble NSPs in all sections of the intestine. 5. Digestibility of protein and NSPs in the ileum and microbial fermentation in the ileum and caeca were not affected by adding enzymes to diets containing L. angustifolius. 6. Enzyme addition to diets with L. albus did not affect digesta viscosity nor concentration of soluble NSPs but caused a significantly (P<0.05) reduced concentration of insoluble NSP in the ileum. 7. Enzyme addition to L. albus significantly (P<0.05) increased NSP digestibility in the ileum but had no effects on protein digestibility and fermentation in the ileum and caeca.  相似文献   

19.
1. A study was undertaken to investigate the susceptibility to peptic digestion of exogenous xylanase (EC 3.2.1.8) from Trichoderma longibrachiatum, added to a rye-based diet for broiler chickens, in order to elucidate its possible site of action. 2. It was also designed to investigate the effects of the enzyme (plus exogenous protease EC 3.4-24.28) when added to a rye-containing diet (60% rye/kg diet) on crypt cell proliferation in the mucosa of the small intestine, on short chain fatty acid (SCFA) concentrations in the small intestine digesta and in portal blood and on nutrient digestibilities. 3. In Experiment 1, the enzymes were added at activities 10x and 30x those recommended in commercial practice, but in Experiment 2 the activities were the recommended levels. 4. A significant proportion (estimated to be 15 to 20%) of the xylanase added at the higher concentration (15,000 and 45,000 units/kg diet) remained active in the small intestine of the growing chicken. 5. The crypt cell proliferation rate in birds fed on the control diet (45 cells/2 h) was significantly higher than in birds fed on the diets supplemented with enzyme at the higher level (29 and 33 cells/ 2 h), but there was no significant effect on SCFA. In birds fed on the diet supplemented with enzyme at the commercial level there was no clear-cut effect on crypt cell proliferation but exogenous xylanase could be detected in the small intestine. Intestinal fluid viscosity was reduced and growth performance of the birds was improved by the supplementation with exogenous enzymes. 6. Part of the improvement in growth performance could be ascribed to a 25% increase in the digestibility of nitrogen and a doubling of the digestibility of fat.  相似文献   

20.
1. The effects of a xylanase on digesta viscosity and starch digestibility throughout the small intestine and volatile fatty acid production in the ileum and caeca were investigated in broilers fed on a low-metabolisable energy wheat diet. 2. The xylanase reduced (P<0.01) duodenal (2.9 vs. 1.7), jejunal (4.6 vs. 2.3) and ileal (14.0 vs. 3.9) digesta viscosities (mPas) and increased AME (P<0.01) of the wheat and starch digestibility (P<0.5) in the jejunum and ileum. Between-bird variability in ME and digestibility of starch was also reduced. 3. Enzyme supplementation reduced (P<0.05) fermentation in the ileum, but increased (P<0.05) it in the caeca. 4. The anti-nutritive effect of soluble non-starch polysaccharides (NSP) is related to their ability to increase digesta viscosity along the gut; this in turn causes changes in gut microflora and efficiency of nutrient utilisation by the chicken. Use of appropriate enzymes is an effective way of dealing with grains with high NSP content in poultry diets.  相似文献   

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