共轭亚油酸对高脂饲料诱导肥胖大鼠脂质蓄积和肠道菌群的影响

目的:以高脂饲料诱导建立肥胖大鼠模型,探讨共轭亚油酸（CLA）干预对肥胖大鼠脂质蓄积和肠道菌群的影响。方法:将40只SPF级雄性SD大鼠按体重随机分为四组,每组10只,除对照组（ND组）以普通饲料喂养外,其余组均以高脂饲料喂养。其中ND组灌胃花生油1 g/kg;高脂模型组（HD组）灌胃花生油1 g/kg;高脂共轭亚油酸低剂量组（LC组）灌胃0.2%共轭亚油酸1 g/kg;高脂共轭亚油酸高剂量组（HC组）灌胃2%共轭亚油酸1 g/kg,干预9周。于实验末采集大鼠粪便后提取粪便中细菌DNA后进行16S rDNA测序,之后麻醉采血后处死,取肝脏、肾周脂肪和睾周脂肪组织,于?80 ℃保存。结果:HD组大鼠体重、内脏脂肪、血清和肝脏甘油三酯和总胆固醇显著高于ND组（P<0.05）,高剂量共轭亚油酸干预可显著降低大鼠体重、血清甘油三酯和总胆固醇及肝脏总胆固醇（P<0.05）;高脂饲料诱导可使大鼠肠道菌群属水平中Eubacterium_coprostanoligenes_group（真杆菌属）、Psychrobacter（嗜冷杆菌属）、Corynebacterium_1（棒状杆菌_1）、Staphylococcus（葡萄球菌属）的相对丰度增加;高剂量CLA干预可改变肥胖大鼠的肠道菌群的组成,如在属水平上显著增加了Bifidobacterium（双歧杆菌属）、Butyrivibrio（丁酸弧菌属）、Ruminococcaceae_UCG-014（瘤胃球菌科_UCG-014）等的相对丰度（P<0.05）,减少了Staphylococcus（葡萄球菌属）、Corynebacterium_1（棒状杆菌_1）等的相对丰度（P<0.05）。结论:共轭亚油酸可降低高脂饲料诱导肥胖大鼠的体重和脂质蓄积,其作用可能与调节大鼠肠道菌群组成有关。     

小米饲料干预对高脂膳食联合STZ诱导糖尿病大鼠肠道菌群的影响（网络首发、推荐阅读）

肠道菌群在Ⅱ型糖尿病的发生和发展过程中发挥重要作用,为了进一步全面探究小米饲料干预对糖尿病大鼠肠道菌群的影响,采用16S rRNA高通量测序技术,分别从横（不同组别）、纵（干预前后）两个维度全面比较了高脂饲料联合链尿佐菌素（Streptozotocin,STZ）诱导糖尿病大鼠经小米饲料饲喂后肠道微生物结构、组成及相对丰度的变化。结果显示,小米饲料干预后,糖尿病大鼠肠道内拟杆菌门和厚壁菌门比值下降,瘤胃球菌属（Ruminococcus_2）和乳酸杆菌的相对丰度显著增加,布劳特氏菌属的相对丰度显著减少,并且均与生理指标具有一定相关性,表明小米饲料干预能够在一定程度上逆转Ⅱ型糖尿病对大鼠肠道菌群的影响,使大鼠肠道微生物组成向着更为健康的方向发展。     

绞股蓝皂苷饮食干预小鼠肥胖及肠道菌群研究

绞股蓝皂苷是绞股蓝中主要的生物活性成分。采用高脂饮食喂食C57BL/6J小鼠,同时给予12周的绞股蓝皂苷灌胃处理,研究绞股蓝皂苷干预对控制小鼠肥胖的作用,同时探究其调节小鼠肠道菌群多样性和组成的作用。结果表明:绞股蓝皂苷饮食干预(600 mg/kg bw/d)能够显著降低因喂食高脂饲料而导致的小鼠体重、体脂率的增长,以及脂肪细胞体积的增大;同时降低血清中低密度脂蛋白-胆固醇、谷丙转氨酶和瘦素的含量,提高高密度脂蛋白-胆固醇的含量。对小鼠粪便进行16S rRNA高通量测序分析结果表明:绞股蓝皂苷干预组可以提高小鼠肠道菌群的α-多样性,并在属水平上提高肠道菌群中颤螺旋菌科属、别普雷沃菌属、狄氏副拟杆菌属、毛螺菌属和伯克氏菌属的相对丰度。     

茶黄素、茶红素与茶褐素对高脂饮食大鼠肠道菌群的影响

以茶黄素、茶红素以及茶褐素为研究对象,研究其对高脂饮食大鼠肠道菌群的影响。即以高脂饮食饲养的方法造模成立营养性肥胖大鼠模型的同时,连续9周灌胃茶黄素、茶红素和茶褐素,其后测定各组大鼠体重、Lee's指数、脂重及血脂水平,通过高通量测序技术,对大鼠肠道内容物肠道菌群进行生物信息学分析。结果表明,和模型对照组相比,灌胃茶黄素、茶红素和茶褐素均可抑制大鼠体重增长(p < 0.05)与Lee's指数(p < 0.01),降低其脂肪重量(p < 0.01或p < 0.05),使其血清内TC、HDL-C、LDL-C、TG含量以及AI指数下降(p < 0.05或p < 0.01),能起到抑制大鼠肥胖效果。进一步分析显示,茶黄素、茶红素和茶褐素能够抑制高脂饮食导致的大鼠肠道内容物肠道菌群丰度及多样性的降低。且从其肠道菌群结构上看,各组大鼠厚壁菌门的相对丰度降低,拟杆菌门的相对丰度得以增加,F/B比值显著降低(p < 0.05)。此外,茶黄素、茶红素和茶褐素还使各组大鼠肠道内属水平上瘤胃球菌相对丰度下降,而乳杆菌、Akkermansia菌和毛螺菌相对丰度存在不同程度回升。即茶黄素、茶红素和茶褐素对高脂饮食大鼠肠道菌群具有正向的调节作用。     

应用Illumina NovaSeq测序技术比较3 种杂粮对大鼠肠道菌群的影响

为探究燕麦、荞麦和小米对健康大鼠肠道结构、肠道菌群及肠道中短链脂肪酸（short-chain fatty acids,SCFAs）含量的影响,本实验将48 只SPF级雄性SD大鼠随机分为4 组（空白对照组（饲喂标准维持饲料）、燕麦组（饲喂含22%（质量分数,下同）燕麦的饲料）、荞麦组（饲喂含22%荞麦的饲料）和小米组（饲喂含22%小米的饲料））,每周测定大鼠体质量,12 周后处死大鼠,取肝脏、结肠组织及结肠内容物,对大鼠肝脏和结肠组织进行病理学检测;应用Illumina NovaSeq高通量测序技术检测大鼠肠道菌群变化;利用液相色谱-质谱联用仪检测大鼠结肠内容物SCFAs含量。结果表明,燕麦可增加大鼠肠道菌群多样性,提高大鼠结肠乳杆菌属（Lactobacillus）和阿克曼氏菌属（Akkermansia）丰度;荞麦和小米可增加厚壁菌门（Firmicutes）相对丰度,降低疣微菌门（Verrucomicrobia）和拟杆菌门（Bacteroidetes）相对丰度;燕麦、荞麦和小米均可降低拟杆菌属（Bacteroides）丰度;燕麦和小米可显著提高大鼠结肠内乙酸和总SCFAs含量（P＜0.05）,小米可显著提高丙酸和异丁酸含量（P＜0.05）。综上,燕麦对大鼠肠道菌群具有一定的改善作用,荞麦和小米对肠道菌群的影响相似度较高,相关研究结果可为谷物功能食品的开发提供科学依据。     

雷公藤红素的肝肾毒性分析及其对高脂饮食小鼠肠道菌群的调节作用

研究高脂饮食和雷公藤红素处理对小鼠肠道菌群及肝肾毒性的影响。用普通鼠粮和高脂鼠粮喂养小鼠,雷公藤红素高、中、低剂量组干预。高通量测序分析小鼠的肠道菌群,检测血清中谷丙转氨酶(ALT)、谷草转氨酶(AST)活性及肌酐(Cr)、血尿素氮(Bun)含量。研究表明高脂饮食和雷公藤红素处理显著影响了小鼠肠道菌群构成,高脂饮食会显著降低小鼠肠道菌群的丰度和多样性,雷公藤红素处理可提高高脂饮食小鼠的肠道菌群的丰度和多样性,并且富集Ruminiclostridium和Anaerotruncus属菌,与对照组相比低、中、高剂量组Ruminiclostridium菌和Anaerotruncus菌含量分别增加51.26%、-44.62%、69.98%和62.45%、28.73%、17.86%。在100μg/kg～400μg/kg的雷公藤红素处理剂量下,AST、ALT活力值及Cr、Bun含量没有显著变化。说明高脂饮食和雷公藤红素处理显著影响了小鼠的肠道菌群结构,并且雷公藤红素在100μg/kg～400μg/kg的处理剂量下未见显著毒性。     

大果山楂发酵液改善高脂饮食小鼠肥胖指标和肠道菌群多样性

研究大果山楂发酵液对高脂饮食小鼠体质量、体脂肪、血脂及肠道菌群的影响。将32只C57BL/6雄性小鼠随机分为4组：正常组、高脂饮食组、低浓度大果山楂发酵液组和高浓度大果山楂发酵液组,处理12周,测定相关肥胖指标和肠道菌群。结果表明,大果山楂发酵液可抑制由高脂饮食导致的体质量、内脏脂肪指数和肝脏指数增加;降低高脂饮食小鼠总胆固醇（TC）、肝甘油三酯（TG）和低密度脂蛋白（LDL）含量;增加高脂饮食小鼠肠道菌群丰度和多样性,提高拟杆菌门（Bacteroidetes）相对丰度,降低厚壁菌门（Firmicutes）相对丰度;8种菌的相对丰度在高脂饮食组和大果山楂发酵液组差异显著（P＜0.05）。     

屎肠球菌B21对高脂饮食Wistar大鼠体重、空腹血糖和粪便菌群的影响

本研究分析了摄食屎肠球菌(Enterococcus faecium)B21菌株对高脂饮食Wistar大鼠体重和空腹血糖的影响;并运用高通量测序技术分析了大鼠肠道菌群多样性的变化。36只Wistar大鼠随机分为正常对照组(NCD)、高脂饮食组(HFD)和E. faecium B21干预组(HFD+B21)。NCD组大鼠喂食普通饲料,HFD组和HFD+B21组大鼠喂食高脂饲料。自第1周起,给予HFD+B21组每只大鼠每天灌胃0.2 mL E. faecium B21(108 CFU/mL)至第7周。收集第7周大鼠粪便,通过高通量测序分析了3组大鼠肠道菌群的结构和组成。结果表明:在第7周时,HFD+B21组(366.51 g)大鼠体重显著高于HFD组(339.43 g,p<0.05)和NCD组(306.84 g,p<0.05),HFD+B21组大鼠(7.63 mmol/L)空腹血糖显著低于HFD组(8.75 mmol/L,p<0.05),且与NCD组无显著性差异(7.08 mmol/L,p>0.05)。HFD+B21组大鼠肠道菌群丰度(ACE值398.12,Chao1值398.49)和多样性最低(Shannon指数3.83),NCD组菌群丰度(ACE值700.57,Chao1值698.07)和多样性(Shannon指数5.06)最高;E. faecium B21的摄入降低了菌群中致病菌属假单胞菌属(Pseudomonas)和脱硫弧菌属(Desulfovibrio)的比率,同时促进了有益菌属布劳特氏菌属(Blautia)的增长。结论:E. faecium B21的摄入能促进高脂饮食Wistar大鼠的体重,降低其空腹血糖且对肠道菌群失衡具有一定的调节作用。     

黑木耳及其多糖对高脂饮食大鼠的降血脂和肠道菌群调节作用

为探讨黑木耳及其多糖的降血脂作用和与肠道菌群的相关性,以5周龄健康雄性SD大鼠为试验对象,分为正常对照组、高脂对照组、黑木耳干预组和黑木耳多糖干预组,干预饲养6周。期间测量大鼠体重、摄食量、血清生化指标,并于解剖后收集肝脏、盲肠内容物及粪便进行病理学和肠道菌群分析。结果表明,黑木耳及其多糖的干预均能够显著降低高脂饮食大鼠血清总胆固醇和低密度脂蛋白含量,提高高密度脂蛋白含量,促进肝脏脂质代谢,减轻脂肪在高脂饮食大鼠肝脏内堆积,其中黑木耳的干预更为显著。黑木耳及其多糖的干预均显著增加了盲肠内短链脂肪酸的含量,推测可能通过上调副拟杆菌属和拟杆菌属等产短链脂肪酸菌群丰度来产生对机体有益的短链脂肪酸以促进血脂代谢。二者还显著提高了大鼠粪便菌群中紫红球菌科或非消化糖杆菌属丰度,显著下调了促炎菌普雷沃菌属丰度,缓解高脂饮食摄入造成的肝炎及其它炎症和疾病。黑木耳调节了与肥胖有关的瘤胃球菌科的丰度,可能是其对高脂血症预防效果更为显著的原因。本研究从调节肠道菌群方面阐明了黑木耳及黑木耳多糖降血脂作用的机理,为通过饮食干预调节肠道菌群,从而改善血脂代谢提供建议。     

青藏高原金露梅茶对高血脂症大鼠肠道菌群的影响

为了探讨青藏高原金露梅（Potentilla fruticosa L.）茶对高脂血症大鼠血脂和肠道菌群的影响。采用高脂饲料饲养Wistar大鼠诱导形成高脂血症模型,用酶联免疫方法（ELISA）考察金露梅三种茶对高脂血症大鼠血脂的影响,同时运用16S rDNA高通量测序分析肠道菌群的多样性和结构变化。结果显示,与模型组比较,金露梅茶组的HDL含量均升高,金露梅红茶组差异显著（P<0.05）。金露梅花茶、绿茶、红茶组大鼠TG、TC含量显著下降（P<0.05,P<0.01）,LDL含量均下降,仅金露梅花茶差异显著（P<0. 05）。同时肠道菌群结果显示,金露梅茶干预后,在门水平上,优势菌群厚壁菌门（Firmicutes）的丰度下调,拟杆菌门 （Bacteroidetes）的丰度上调,属水平上,大鼠肠道内乳杆菌属（Lactobacillus）、拟杆菌属（Bacteroides）丰度明显上调,而毛螺菌科中未分类的属（unidentified_Lachnospiraceae）、瘤胃菌科中未分类的属（unidentified_Ruminococcaceae）丰度则明显下调。金露梅花茶、绿茶、红茶具有调节高脂血症大鼠血脂及其肠道菌群谱的作用,使其有向正常对照组恢复的趋势,推测金露梅茶可能经肠道菌群干预脂质代谢途径发挥降血脂的功效。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.