Dietary xylo‑oligosaccharides and arabinoxylans improved growth efficiency by reducing gut epithelial cell turnover in broiler chickens

Background One of the main roles of the intestinal mucosa is to protect against environmental hazards.Supple-mentation of xylo-oligosaccharides(XOS)is known to selectively stimulate the growth of beneficial intestinal bacteria and improve gut health and function in chickens.XOS may have an impact on the integrity of the intestinal epithelia where cell turnover is critical to maintain the compatibility between the digestive and barrier functions.The aim of the study was to evaluate the effect of XOS and an arabinoxylan-rich fraction(AXRF)supplementation on gut func-tion and epithelial integrity in broiler chickens.Methods A total of 128 broiler chickens(Ross 308)were assigned into one of two different dietary treatments for a period of 42 d:1)control diet consisting of a corn/soybean meal-based diet;or 2)a control diet supplemented with 0.5%XOS and 1%AXRF.Each treatment was randomly distributed across 8 pens(n=8)with 8 chickens each.Feed intake and body weight were recorded weekly.On d 42,one male chicken per pen was selected based on aver-age weight and euthanized,jejunum samples were collected for proteomics analysis.Results Dietary XOS/AXRF supplementation improved feed efficiency(P<0.05)from d 1 to 42 compared to the con-trol group.Proteomic analysis was used to understand the mechanism of improved efficiency uncovering 346 dif-ferentially abundant proteins(DAP)(Padj<0.00001)in supplemented chickens compared to the non-supplemented group.In the jejunum,the DAP translated into decreased ATP production indicating lower energy expenditure by the tissue(e.g.,inhibition of glycolysis and tricarboxylic acid cycle pathways).In addition,DAP were associated with decreased epithelial cell differentiation,and migration by reducing the actin polymerization pathway.Put-ting the two main pathways together,XOS/AXRF supplementation may decrease around 19%the energy required for the maintenance of the gastrointestinal tract.Conclusions Dietary XOS/AXRF supplementation improved growth efficiency by reducing epithelial cell migration and differentiation(hence,turnover),actin polymerization,and consequently energy requirement for maintenance of the jejunum of broiler chickens.

Valorization of wheat bran arabinoxylan: A review on nutritional and materials perspectives

Wheat bran, a principal byproduct of flour milling, stands as an abundant source of dietary fiber, yet its economic potential remains under-exploited in current forage applications. Arabinoxylan(AX), constituting the core of dietary fiber, emerges as a versatile compound with multifaceted functionalities. Its nutritional significance,coupled with its role in cereal food processing, has prompted a surge of studies focusing on the valorization of wheat bran AX. Moreover, the hydrolyzed derivative, arabinoxylan oligosaccharides(AXOS), demonstrates prebiotic and antioxidant properties, offering potential avenues to mitigate the risk of chronic diseases. This review summarizes current knowledge on the valorization of wheat bran AX in terms of the processing and nutritional properties of AX. Moreover, multiple novel applications of AX in the materials area, including biodegradable food packaging films, delivery of bioactive substances as nanoparticles, and the manufacture of food emulsifiers, are also highlighted to extend the utilization of AX. This review underscores the immense potential of wheat bran AX, advocating for its exploitation not only as a nutritional asset but also as a primary ingredient in advanced materials. The synthesis of nutritional and materials perspectives accentuates the multifaceted utility of wheat bran AX, thereby paving the way for sustainable valorization pathways. By unraveling the latent potential within AX, this paper advocates for the holistic and sustainable utilization of wheat bran in diverse, value-added applications.

Debranching enzymes decomposed corn arabinoxylan into xylooligosaccharides and achieved prebiotic regulation of gut microbiota in broiler chickens

Background Corn arabinoxylan(AX)is a complicated and multibranched antinutritional factor,thereby proving the use of endo-xylanase(EX)to be marginally valid.This study focused on specific types of AX-degrading enzymes(ADEs)to exert the synergy of debranching enzymes and track the prebiotic potential of enzymatic hydrolysates.This study investigated the effects of ADEs on the growth performance,intestinal histomorphology,absorption functions,changes in polysaccharide components,fermentation,and gut microbiota of broiler chickens.Five hundred seventysix five-day-old Arbor Acres male broiler chickens were randomly allocated into eight treatments with six replicates each.Corn basal diets supplemented with or without enzymes were fed for a 21-day period,specifically including EX,its compatible use with arabinofuranosidase(EXA)or ferulic acid esterase(EXF),and compound groups with the above three enzymes(XAF).Results Specific ADEs stimulated the jejunal villus height and goblet cell number and evidently decreased the crypt depth(P<0.05),while the ratio of ileal villus height to crypt depth was significantly increased in EXF(P<0.05).Maltase activities of ileal mucosa in XAF groups were extremely enhanced(P<0.01),and EX boosted the activity of Na+-K+ATPase in the small intestine(P<0.01).The insoluble AX concentrations comparatively lessened,thereby notably raising the sundry xylooligosaccharide(XOS)yield in the ileal chyme(P<0.05),which was dominant in xylobiose and xylotriose.Improvements in the abundance and diversity of ileal microbial communities within the EXA,EXF,and XAF treatments were observed(P<0.05).Positive correlations between microbiota and XOS were revealed,with xylobiose and xylotriose being critical for ten beneficial bacteria(P<0.05).EXF increased the BWG and FCR of broiler chickens in this phase(P<0.05),which was attributed to the thriving networks modified by Lactobacillus.The intracecal contents of acetic acid,butyric acid,and propionic acid were greatly enhanced in most ADE groups,such as EXF(P<0.05).Conclusions Debranching enzymes appreciably targeted corn AX to release prebiotic XOS in the posterior ileum and facilitated intracaecal fermentation.It was beneficial for improving gut development,digestion and absorption and modulating the microflora to promote the early performance of broiler chickens.

Combinatorial Enzyme Approach to Convert Wheat Insoluble Arabinoxylan to Bioactive Oligosaccharides

Combinatorial enzyme technology was applied for the conversion of wheat insoluble arabinoxylan to oligosaccharide structural variants. The digestive products were fractionated by Bio-Gel P4 column and screened for bioactivity. One fraction pool was observed to exhibit antimicrobial property resulting in the suppression of cell growth of the test organism ATCC 8739 E. coli. It has a MIC value of 1.5% (w/v, 35°C, 20 hr) and could be useful as a new source of prebiotics or preservatives. The present results further confirm the science and useful application of combinatorial enzyme approach.

Release of Arabinose from Wheat Insoluble Arabinoxylan by the Action of α-L-Arabinofuranosidase in Synergism with Endo-Xylanases

Wheat arabinoxylan (water-insoluble fraction) contains ~36% arabinose which may include both singly or doubly substitutions at C2/C3 of the Xylp units. α-L-Arabinofuranosidses (ABFs) of two GH families were analyzed for their respective activities on the hydrolysis of Xylp-Araf. BaABF (GH43) produced twice the yield of arabinose residues from the heteroxylan compared to AnABF (GH51) under the same reaction conditions. Two endo-xylanases (of GH10 and 11) also showed differential hydrolytic activities on the Xylp chain, with the GH10 XYN-ATM double the amount of reducing sugar yield (as xylose equivalent) than using the GH11 XYN-M3. When the ABF and XYN were combined in optimial ratios, a synergistic increase of 73.8% in arabinose yield was observed.

Genotypic and Environmental Variations of Arabinoxylan Content and Endoxylanase Activity in Barley Grains

Arabinoxylan （AX） content in barley grains is an important quality determinant when barley is used as raw material of malt or beer production. The cultivar and environmental variations of total arabinoxylan （TAX）, water extractable arabinoxylan （WEAX） and endoxylanase activity （EA） were investigated using eight barley cultivars growing at seven locations with diverse environmental conditions. The results showed that both barley cultivar and location significantly affected the TAX, WEAX and EA levels, but the variations of TAX content and EA were mainly attributed to cultivar, while the impact of location on WEAX content was greater than that of cultivar. Correlation analysis indicated that TAX was significantly correlated to WUAX.

Effect of Added Arabinoxylans Isolated from Good and Poor Chapati Making Wheat Varieties on Rheological Properties of Dough and Chapati Making Quality

Arabinoxylans are the major non-starch polysaccharides in wheat and are reported to influence quality of bakery products. Arabinoxylans were isolated from good and poor chapati making varieties, added them at different levels (0.25 and 0.5 g/100g) to the same flour, interchanged with other varieties and determined the effect of arabinoxylans on rheological properties of dough and chapati making quality. Rheological properties were improved upon adding isolated arabinoxylans of good chapati making varieties to flours. Interestingly, addition of isolated arabinoxylans of good chapati making varieties to poor chapati making varieties had significantly improved the chapati quality. Sensory studies showed that chapatis prepared from flour added with arabinoxylans of good chapati varieties had soft texture and high overall quality scores. These changes are attributed to differences in their arabinose/xylose ratio. Thus, results indicated that addition of isolated arabinoxylans of good chapati making flour improved the chapati quality of poor chapati making flour.

What Are the Characteristics of Arabinoxylan Gels?

Arabinoxylan gels are commonly characterized to determine the feasibility of utilizing them in numerous applications such as drug delivery systems. The general characteristics of numerous types of arabinoxylan gels as well as their susceptibility to degradation are discussed in this manuscript. There are two main types of arabinoxylan: water-extractable and alkali-extractable. The physicochemical characteristics of the arabinoxylan determine its extractability and gelling characteristics. Gels can be created from numerous types of arabinoxylan including wheat (Triticum aestivum L.) and maize (Zea mays L.). These gels can also be developed with the addition of protein and/or β-glucan, which results in modified mechanical properties of the gels. To create a sound gel, arabinoxylan must be cross-linked, which is often done through ferulic acid. When this takes place, the gel developed is thermo-irreversible, unsusceptible to pH and electrolyte interactions, and does not undergo syneresis during storage. Despite these strengths, arabinoxylan gels can be broken down by the enzymes produced by Bifidobacterium, which is present in the human large intestine. After further development and research on these gels, they could be utilized for many purposes.

Reduced-particle size wheat bran and endoxylanase supplementation in broiler feed affect arabinoxylan hydrolysis and fermentation with broiler age differently

Since the caecal microbiota of young broilers are not yet able to ferment the dietary fibre(DF)fraction of the feed to a large extent,increasing the accessibility of DF substrates along the gastrointestinal tract is crucial to benefit from the health stimulating metabolic end-products(e.g.butyric acid)generated upon microbial DF fermentation.Therefore,the present study aimed to evaluate the potential of reduced-particle size wheat bran(RPS-WB)and endoxylanases as feed additives to stimulate arabinoxylan(AX)hydrolysis and fermentation along the hindgut of young broilers.To this end,RPS-WB and endoxylanase supplementation were evaluated in a 2×2 factorial design using a total of 256 male 1-d-old chicks(Ross 308).Broilers were assigned to 4 dietary treatments:a basal wheat-based diet with(1)no feed additives(control,CTRL),(2)an endoxylanase(XYL;Econase XT 25 at 0.10 g/kg diet),(3)1%wheat bran with an average reduced particle size of 297μm(RPS-WB)and(4)an endoxylanase and 1%RPS-WB(RPS-WB+XYL).Each dietary treatment was replicated 8 times and on d 10 and 28,respectively,24 and 16 broilers per treatment group were euthanised to analyse AX degradation,short-chain fatty acid production and digesta viscosity in the ileum and caecum.Broilers receiving XYL in their diet showed increased AX solubilisation and fermentation at both d 10 and 28 compared to the CTRL group(P<0.05).Adding RPS-WB to the diet stimulated wheat AX utilisation by the primary AX degraders in the caecum at 10 d of age compared to the CTRL group,as observed by the high AX digestibility coefficient for the RPS-WB supplemented group at this young age(P<0.05).At 28 d,RPS-WB supplementation lowered body-weight gains but increased butyric acid concentrations compared to the XYL and CTRL group(P<0.05).Although no synergistic effect for RPS-WB+XYL broilers was observed for AX hydrolysis and fermentation,these findings suggest that both additives can raise a dual benefit to the broiler as a butyrogenic effect and improved AX fermentation along the ileum and caecum were observed throughout the broiler's life.

玉米芯功能性低聚糖分级纯化及抗氧化活性研究

探究玉米芯功能性低聚糖分级纯化前后不同组分的组成、理化性质和抗氧化活性。以玉米芯为原料,采用活性炭柱层析法对玉米芯功能性低聚糖进行分级纯化,对纯化前后组分的聚合度、相对分子质量、阿魏酸基团以及红外光谱特性进行分析,并对酶解低聚糖粗提物(EH)及其纯化组分的自由基清除能力和抑制脂质过氧化能力进行比较分析。结果表明:活性炭水洗脱低聚糖组分(WO)、醇洗脱低聚糖组分(EO)均主要由木糖和阿拉伯糖组成,其中WO含有结合态阿魏酸,为阿魏酰阿拉伯低聚木糖;EO不含结合态阿魏酸,为阿拉伯低聚木糖。EH及其纯化组分WO、EO均具有一定的清除自由基(DPPH·、·OH、ABTS^(+)·)能力和抑制脂质过氧化能力,且随浓度的增加而增加,WO抗氧化活性最强,EH次之,EO抗氧化活性较弱。

阿拉伯木聚糖对面团及面制品品质影响的研究进展

阿拉伯木聚糖(arabinoxylan,AX)作为一种膳食纤维,在面团加工过程中会与其主要组分发生相互作用,从而影响面团特性和面制品品质。文章分析了AX与面团中面筋蛋白和小麦淀粉间的相互作用,总结归纳了其对面团持水性、流变性和发酵特性等方面的影响规律,概述了近年来国内外关于AX在应用于蒸煮类、焙烤类、油炸类面制品等方面所取得的研究成果,指出了目前在AX的精细结构、链构象特征、量效关系等方面需要解决的一些重要问题,并针对这些问题提出了今后的研究建议,以期推动AX在面制品行业中的理论研究和实际应用。

阿拉伯木聚糖-甘薯淀粉复合体系理化特性表征

探究了阿拉伯木聚糖(arabinoxylan,AX)-甘薯淀粉(sweet potato starch,SPS)复合体系的糊化、质构、流变和水分迁移等理化特性。添加不同浓度的AX代替等量淀粉配置成复合体系,利用布拉班德黏度仪、扫描电子显微镜、流变仪等分析手段,对AX-SPS复合体系的理化特性进行表征。结果表明,与天然SPS相比,AX-SPS复合体系的黏度值、回升值、崩解值降低,糊化温度有所升高;随着AX添加比例的增大,淀粉凝胶断层表面粗糙且孔洞增多;静态流变学分析表明,AX-SPS复合体系均为典型剪切稀化的假塑性流体,并随着AX添加比例的增大,假塑性行为有所减弱;动态流变学分析表明AX的添加降低了复合体系的储存模量(G′)和损耗模量(G″);质构和低场核磁分析表明,AX的加入降低了SPS凝胶的硬度、弹性,改善了质地,提高了保水性;红外光谱分析表明,AX添加量的增加使淀粉的双螺旋结构和有序性破坏程度增大,复合体系氢键作用力增强。综上,AX的添加改善了SPS的糊化、流变、质构和持水性等理化特性,使SPS在食品、医药及化工等领域具有更广阔的应用前景。

玉米麸皮阿拉伯木聚糖复合纳米载体负载香草醛及其抑菌性能研究

本研究构建了负载香草醛的玉米麸皮阿拉伯木聚糖(Arabinoxylan,AX)与玉米醇溶蛋白(Zein)复合纳米载体,通过多糖与蛋白质的相互作用稳定体系,提高香草醛的稳定性并探讨了复合纳米载体对单增李斯特菌和大肠杆菌的抑菌效果。用80%和90%乙醇沉淀得到两个玉米麸皮粗多糖组分,通过阴离子交换柱纯化后,得到四个组分(F80-1、F80-2、F90-1及F90-2),采用气相色谱法鉴定了各组分的单糖组成。结果表明,各组分阿拉伯糖和木糖总含量分别为67.41%、76.12%、77.16%和84.89%,四个组分复合纳米载体对香草醛的包封率分别达到了81.18%、69.36%、86.80%和88.48%,荧光光谱法和差示扫描量热法(DSC)验证了香草醛在复合纳米载体中的包埋效果及分子间相互作用,抑菌试验结果表明,F80-2制备的复合纳米载体抑制单增李斯特菌效果最好,F90-2复合纳米载体抑制大肠杆菌效果最好。

Effect of arabinoxylo-oligosaccharides and arabinoxylans on net energy and nutrient utilization in broilers

Arabinoxylo-oligosaccharides(AXOS) are hydrolytic degradation products of arabinoxylans(AX) that can be fermented by the gut microbiota, thus potentially displaying prebiotic properties. This study examined the effects of AX and AXOS on net energy(NE) and nutrient utilization in broilers. Ross 308 broilers(n = 90, 30 birds per treatment) were fed wheat-soybean diets supplemented with pure AX, AXOS produced by exposing the AX to xylanase in vitro(AXOS), or AX with xylanase(AX + E) from d 10 to 21.Performance parameters were measured from d 10 to 21. On d 15, 10 birds per treatment were allocated to closed-circuit net energy chambers to assess the impact of AX and AXOS on dietary energy utilization,through assessment of both metabolisable energy(ME) and NE. Ileal and caecal digesta samples were collected on d 21 to determine the effect of AX and AXOS on ileal and total tract dry matter digestibility,ileal digestible energy, digesta pH, short chain fatty acids(SCFA) and microbiota concentration. Feed conversion ratio was numerically the lowest in birds fed the diet supplemented with AXOS, which is 1.26 compared to 1.37 and 1.30 for AX and AX + E, respectively. Ileal dry matter digestibility was higher in birds fed AXOS than those fed AX(P = 0.047). Ileal digestible energy and total tract dry matter digestibility were higher in birds fed AXOS than those fed AX or AX + E(P = 0.004 and P = 0.001,respectively). Birds fed AXOS had higher ME intake(P = 0.049) and nitrogen retention(P = 0.001) and a strong trend of higher NE(P = 0.056), NE intake(P = 0.057) and retained energy(P = 0.054) compared to those fed AX. Ileal total SCFA, lactic and formic acid concentrations were higher in birds fed AXOS than those fed AX(P = 0.011, P = 0.012 and P = 0.023, respectively). Birds fed AXOS or AX + E had higher caecal total SCFA, acetic, butyric and isovaleric acid concentrations compared to those fed AX(P = 0.001,P = 0.004, P = 0.016 and P = 0.008, respectively), and caecal propionic acid concentration was higher in birds fed AX + E than those fed AX(P = 0.050). Ileal and caecal microbiota concentrations were numerically higher and pH was lower in birds fed AXOS and AX + E than those fed AX. Results from this study indicate that feeding AXOS directly is more efficient than AXOS generation in the gastrointestinal tract, and suggest that AXOS has a potential to be an efficacious prebiotic in broiler diets.

酶响应海藻酸钠/阿拉伯木聚糖丁酸梭菌双重微胶囊体外耐受性分析

选用废弃米糠提取的益生多糖阿拉伯木聚糖(AX)和海藻酸钠(SA)双重微胶囊包埋丁酸梭菌,并在其表面涂层硫酸鱼精蛋白(PRM),提高菌株环境耐受性的同时实现其靶向递送。结果表明:米糠来源的2种AX总糖含量高达(81.86±0.67)%和(76.87±0.12)%,且单糖组成以木糖和阿拉伯糖为主;2种AX能与漆酶作用形成结构密集的网状凝胶;此外,AX还可作为丁酸梭菌利用的益生元,发酵可产生对肠道有益生作用的乳酸、乙酸和丁酸;采用锐孔凝固法结合静电自组装制备得到(SA AX)@PRM复合微胶囊,将其在模拟胃液和高胆盐处理后,存活率相较于游离菌体分别提高了32.4%和16.2%;在模拟消化液释放实验中,(SA AX)@PRM包埋的丁酸梭菌在胃液中保持良好的稳定性,且转移至模拟肠液后可被胰蛋白酶崩解释放,进而实现益生菌在结肠中的靶向释放。

阿拉伯木聚糖、β-D-葡聚糖和α-纤维素涂层对杏果活性氧代谢的影响

使用阿拉伯木聚糖(arabinoxylan,AX)、(1,3;1,4)-β-D-葡聚糖((1,3;1,4)-β-D-glucan,BG)和α-纤维素复合溶液对采后杏果进行涂层处理,探究谷物细胞壁多糖涂层对采后杏果活性氧代谢系统的影响,并阐明其作用机理。结果表明:涂层能够有效抑制丙二醛和活性氧含量的上升,对照组的丙二醛、H2O2和O2-含量分别比ABF-C8处理组(α-纤维素质量浓度8 g/100 mL)高37.50%、33.33%和57.14%;此外,涂层处理还能维持杏果的抗氧化能力和抗氧化酶活性,其抗坏血酸和总酚含量分别比对照组高73.33%和8.40%;小麦细胞壁多糖涂层能够延缓杏果实呼吸过程中活性氧的产生和积累,从而保持细胞膜的完整性,同时涂层能够使水果和外界环境形成气体和水分之间的屏障,维持活性氧清除酶活性及抗氧化能力,从而延长采后杏果的贮藏期。

Ferulic acid mediates prebiotic responses of cereal-derived arabinoxylans on host health

Dietary fiber is named as “the 7th nutrient” for humans, which is beneficial to improve intestinal healthand prevent metabolic disease of the host. Mechanisms of dietary fiber administration on improved hosthealth are mediated by short chain fatty acids (SCFA), which are reported to activate G protein-coupledreceptors (GPR) and suppress activity of histone deacetylase (HDAC) to down-regulate expression ofnuclear factor-к-gene binding (NF-кB) signaling. Arabinoxylan is fermented by gut microbiota to produceSCFA and improved microbial community composition, intestinal barrier functions and host health.Interestingly, the latest publications have observed that ferulic acid combined with the arabinose inarabinoxylans from various cereal grains can be released through gut microbial fermentation. Ferulic acidcan improve antioxidase activity and decrease reactive oxygen species (ROS) concentration by activatingthe signaling pathway of Kelch-like ECH-associated protein-1 and nuclear factor E2-related factor-2(Keap1-Nrf2). However, the role of ferulic acid in cooperation with SCFA produced from microbialfermentation of cereal-derived arabinoxylan to regulate the intestinal health and host metabolisms, hasbeen widely unclear. This review summarizes the potential mechanisms of ferulic acid from microbialfermentation of cereal-derived arabinoxylans on immunological functions and physiological metabolismsof the host. The evidence presented in the review indicates that dietary supplementation withcereal-derived arabinoxylans improves antioxidant capacity of intestinal epithelial cells due to theproduction of ferulic acid and SCFA from microbial fermentation. Ferulic acid can cooperate with SCFA toregulate intestinal integrity and immunological functions of the host. Peroxisome proliferator activatedreceptorg (PPARg) may play an important role in integrating ferulic acid and SCFA to regulate host healthand metabolism.

Feed endoxylanase type and dose affect arabinoxylan hydrolysis and fermentation in ageing broilers☆

Despite the general use of endoxylanases in poultry feed to improve broiler performance,the abundance of different endoxylanase products and the variable response to their application in the field prevent a clear understanding of endoxylanase functionality in vivo.To gain insight into this functionality,we investigated the impact of endoxylanase type(Belfeed from Bacillus subtilis versus Econase XT from Nonomuraea flexuosa)and dose(10,100,1,000 mg/kg)in combination with broiler age on arabinoxylan(AX)hydrolysis and fermentation in broilers(Ross 308)fed a wheat-soy based diet.In a digestibility trial and a performance trial,a total of 1,057 one-day-old chicks received the control diet or 1 of the 6 endoxylanase supplemented wheat-soy based diets with,respectively,5 replicate cages and 8 replicate pens per dietary treatment per trial.The AX content and structure,the AX digestibility values and the short-chain fatty acids produced were analysed at the level of the ileum,caeca and excreta at d 11 and 36.Endoxylanase supplementation resulted in a more extensive solubilisation of wheat AX and a reduction in the intestinal viscosity compared to the control(P<0.05).A high endoxylanase dose was,however,required to obtain increased hydrolysis of the dietary AX along the gastrointestinal tract against the control(P<0.001).Depending on the type of endoxylanase,a pool of AX with distinct physicochemical properties was created.The B.subtilis endoxylanase created a large pool of soluble AX in the ileum,thereby increasing ileal viscosity compared to broilers fed an endoxylanase from N.flexuosa(P<0.001).The N.flexuosa endoxylanase mainly triggered caecal AX fermentation in young broilers,by delivering easily fermentable AX substrates with a low degree of polymerisation(P=0.03).The effects were particularly present in young broilers(d 11).From this study,it is clear that the type and dose of endoxylanase added to wheat-soy based diets determine the nature of AX substrates formed.These,in turn,affect the intestinal viscosity and the interplay between the dietary AX compounds and microbiota,hence dictating AX digestion at young broiler ages and performance outcomes towards slaughter age.

刺梨果渣阿拉伯木聚糖对α-淀粉酶的抑制及其酵解特征研究

为挖掘刺梨果渣的应用价值,研究了果渣中阿拉伯木聚糖(arabinoxylan, AX)的降糖活性与酵解特征。以分子对接技术、酶抑制、酶动力学、荧光光谱来评价AX的降糖能力及原理,以体外模拟结肠发酵来分析AX被微生物发酵利用情况。分子模拟对接结果表明AX与α-淀粉酶之间通过氢键等作用结合而发挥抑制作用,体外降糖实验结果表明,AX对α-淀粉酶具有一定的抑制作用,抑制类型为混合型抑制,且AX与酶发生静态猝灭。体外模拟发酵实验表明,发酵过程中pH值显著下降,从8.8下降到5.1左右,且在同一发酵时间内,AX组的pH值大多低于对照组,这可能与AX组产生的短链脂肪酸(short-chain fatty acids, SCFAs)水平较高有关。另外,在体外发酵过程中,SCFAs含量显著增加,24 h后达到1 705.74μg/mL。因AX对α-淀粉酶有较好的抑制能力,且SCFAs在维持宿主肠道稳态和健康状态方面起着关键作用,所以AX有望成为一种具有降糖及促进肠道健康的功能性食品。该研究为刺梨果渣的高效利用以及在功能活性方面的研究提供理论参考。

基于核磁共振氢谱代谢组学研究阿拉伯木聚糖及其复合多糖对高脂饮食诱导肥胖小鼠粪便代谢物的影响

为探究阿拉伯木聚糖及其复合多糖对高脂饮食诱导肥胖小鼠粪便代谢产物的影响,将16只雄性ICR/KM小鼠随机分为4组,包括正常饮食组、高脂饮食组、添加阿拉伯木聚糖的高脂饮食组和添加阿拉伯木聚糖+β-葡聚糖的高脂饮食组,通过核磁共振氢谱代谢组学技术研究粪便代谢物的组成及含量。结果表明:4组粪便代谢物中共定性出67种小分子化合物,包括氨基酸、肽、有机酸、碳水化合物、核苷、核苷酸及其衍生物等。与正常饮食组相比,高脂饮食组小鼠粪便代谢物中胆酸盐、黄嘌呤和焦谷氨酸的含量显著升高(P<0.05);缬氨酸、3-氧丁酸、4-羟基苯乙酸甲酯、3,4-二羟基苯乙酸、乙酸苯酯、谷氨酰胺、异亮氨酸和天冬氨酸的含量显著降低(P<0.05)。与高脂饮食组相比,补充阿拉伯木聚糖组小鼠粪便代谢物中谷氨酰胺、乙酸盐、4-羟基苯乙酸甲酯、葡萄糖、天冬酰胺、异丁酸和苏氨酸的含量显著升高(P<0.05);烟酸、焦谷氨酸和胆酸盐的含量显著降低(P<0.05)。其中,与添加阿拉伯木聚糖的高脂饮食组相比,补充阿拉伯木聚糖+β-葡聚糖的高脂饮食组小鼠粪便代谢物中焦谷氨酸的含量显著升高(P<0.05);乙酸盐、丁酸盐、葡萄糖、谷氨酰胺、异丁酸和丙酸的含量显著降低(P<0.05)。代谢通路和富集分析结果表明主要的作用途径包括酮体的合成和分解,苯丙氨酸、酪氨酸和色氨酸的生物合成,酪氨酸代谢,丁酸盐代谢,丙氨酸、天冬氨酸和谷氨酸的代谢。综上,补充阿拉伯木聚糖及其复合多糖能改善高脂饮食诱导肥胖小鼠的粪便代谢组学特征。