大鼠粪便中短链脂肪酸的快速提取与分析方法

目的在气相色谱法(Gas Chromatography,GC)测定大鼠粪便中短链脂肪酸(Short Chain Fatty Acid,SCFA)方法的基础上,探索更高效的大鼠粪便前处理法。方法改变前处理方法的离心时间和离心速率对大鼠粪便进行前处理,利用GC大鼠粪便前处理的效果。结果根据离心速率和离心时间分别选择9个条件进行优化,超纯水提取法(13 000 r/min,25 min,4℃)和硫酸提取法(11 000 r/min,25 min,4℃)分别在离心处理样品后,利用GC可测得到5种SCFA且RSD5.00%,二者进行实验对比,测得的5种SCFA含量差异无统计学意义(P0.05),硫酸提取法稳定性优于超纯水提取法,且具有良好线性关系(r≥0.99),稳定性RSD为3.40%～4.93%,加标回收率为82.66%～104.76%(RSD≤3.70%)。结论硫酸提取法可简便、高效提取大鼠粪便中SCFA,此法是提取大鼠粪便中SCFA较为理想的前处理方法,供后续研究选用。     

不同膳食模式及添加大豆低聚糖对肠道短链脂肪酸的影响

目的:探讨不同膳食模式及添加大豆低聚糖对肠道内短链脂肪酸(short-chain fatty acids,SCFA)的数量和种类的影响。方法:选择12名20～25岁健康在校大学生,分三阶段给予三种不同膳食及服用大豆低聚糖,每一阶段第1w食用三种实验膳食(1.低动物性食物模式LAFD,2.动植物食物平衡模式BD,3.高动物性食物模式HAFD),第2w添加大豆低聚糖,第3w恢复原实验膳食,准备下一阶段试验。试验共进行9w,每周前后收集粪便,利用毛细管柱顶空气相色谱法测定粪便中的SCFA。结果:LAFD干预后SCFA总量增加,差异有显著意义(P<0.05),且以乙酸、丁酸增加为主。BD和HAFD干预后SCFA总量没有改变。在三种干预膳食基础上添加大豆低聚糖后,LAFD时SCFA总量变化不明显,BD和HAFD时SCFA总量均有显著增加(P<0.05),且BD时以乙酸、丙酸增加为主,HAFD时以丙酸、丁酸增加为主。结论:膳食中植物性食品或动物性食品对人体肠道内SCFA的含量、种类均有影响。大豆低聚糖添加在动植物平衡膳食模式和高动物性食物膳食模式下效果更好。     

富含抗性淀粉转基因大米对大鼠肠道健康的影响

目的研究富含抗性淀粉转基因大米对大鼠肠道健康的影响。方法48只健康成年雄性SD大鼠按体重随机分为4组:分别给予非转基因大米最大量掺入的饲料(No-GM组)、转基因大米最大量和半量掺入的饲料(GM组、Half-GM组)和正常对照饲料重(ND组)。喂养5w后连续收集4d粪便;6w后处死大鼠并收集盲肠、结肠内容物,测定内容物和肠壁量、pH值、短链脂肪酸(SCFA)等反映肠道健康的指标。结果GM组的体重接近ND组,显著低于No-GM组。与No-GM组和ND组相比,GM组和Half-GM组粪便量、粪便水分、盲肠壁以及内容物含量显著增加,并存在显著的量效关系(P<0.05)。GM组结肠壁质量与No-GM组和ND组也有显著差异。盲肠、结肠和粪便中SCFA的含量逐渐降低,除了Half-GM组结肠中丁酸含量与其他各组没有差异外,GM组和Half-GM组盲肠、结肠中SCFA含量与No-GM组和ND组相比都有增加,各组大鼠粪便中丁酸含量的差异消失,但是乙酸和丙酸含量仍然存在差异。GM组和Half-GM组粪便和盲肠的pH值非常显著低于No-GM组和ND组。结论抗性淀粉转基因大米能改善大鼠肠道健康。     

粪便中6种短链脂肪酸的气相色谱快速检测法

目的 建立粪便中乙酸、丙酸、正丁酸、异丁酸、正戊酸和异戊酸等六种短链脂肪酸（SCFAs）的快速提取及气相色谱定量检测方法。方法 粪便样本分别采用纯水和盐酸溶液（pH = 2）提取,静置、离心后,上清液中的SCFAs采用气相色谱法测定。以正丁醇为内标,保留时间定性,峰面积定量。结果 本法线性关系良好,水提取和酸提取的加标回收率分别为78.8%～115%和85.7%～130%,且无统计学差异（P＞0.05）。比较人和鼠的粪便水提法所得SCFAs含量与参考文献检测结果吻合。结论 本法高效、稳定,可应用于大批粪便样本6种短链脂肪酸的快速测定。     

高直链玉米淀粉对大鼠肠道发酵影响的研究

目的:研究高直链玉米淀粉(high amylase corn starch,HACS)对大鼠肠道发酵的影响。方法:将30只Wistar成年雌鼠随机分为5组,分别喂不添加(对照)和添加5%、10%、20%、30%HACS的饲料。喂养4w后,解剖取小肠、盲肠及盲肠内容物,测定各组体重、饲料效率及淀粉消化率、小肠内容物、盲肠内容物、盲肠组织重量、表面积及盲肠中短链脂肪酸(SCFA)和pH值等。结果:随着饲料中HACS添加量的增加,淀粉表观消化率显著降低,肠道未消化物重量及粪重显著增加。添加20%和30%HACS组的盲肠中乙酸、丙酸、丁酸、丁二酸和总SCFA及盲肠组织重量均显著高于对照组,但30%HACS组的丙酸、丁酸和总SCFA均低于20%HACS组。添加HACS各组盲肠的pH值均低于对照组,其中20%和30%HACS组达显著水平(P<0.05)。结论:饲料中添加HACS能明显提高盲肠中SCFA的产量,且有明显的剂量关系。     

短链脂肪酸与结直肠肿瘤细胞凋亡关系的研究

目的:研究结直肠肿瘤病人粪便短链脂肪酸(SCFA)的影响因素及其与肿瘤细胞凋亡的关系. 方法:收集首次确诊拟行根治手术的结直肠癌病人的资料,采集描述性指标(年龄、性别、肿瘤家族史、烟酒史)、肿瘤指标(大小、临床分期、局部和远处转移)、营养相关指标(身高、体重、血红蛋白、清蛋白)和膳食摄入情况.检测肿瘤细胞凋亡情况和粪便SCFA水平. 结果:共收集35例病人资料.所有病人均能保证每天摄入蔬菜,但粗粮、奶和酸奶制品、水果摄入量的摄入频次较推荐量明显不足.年龄、性别、肿瘤部位、临床分期、蔬菜、水果和粗粮摄入频数、饮酒、肿瘤家族史等,未对病人粪便SCFA水平产生明显影响.酸奶摄入≥1次/周的结直肠肿瘤病人较＜1次/周者粪便丁酸含量明显升高.吸烟则明显降低粪便丁酸水平. 结论:吸烟可降低结直肠肿瘤病人粪丁酸含量,酸奶摄入≥1次/周者,可升高粪丁酸含量.在不吸烟和酸奶摄入≥1次/周的病人中,有增加肿瘤细胞凋亡的趋势.     

产丁酸菌与老年代谢性疾病的相关研究

目的探讨产丁酸菌与老年代谢性疾病的相关性。方法采集浙江省杭州市某社区117例≥75岁老年志愿者粪便,根据志愿者实际情况分为老年健康组,老年高血压组,老年高血压合并冠心病组,老年高血压合并糖尿病组。粪便分装后统一提取DNA,采用定量聚合酶链反应(Q-PCR)检测其肠道中的7种产丁酸菌含量,采用SPSS 17.0软件进行独立样本t检验。结果高血压合并冠心病组的普拉梭菌fpra(P=0.008)、Clostridial cluster IV(P=0.010)和Atopobium cluster(P=0.005)高于高血压组;高血压合并糖尿病组Eubacterium Rectal(P=0.020)和Atopobium cluster(P=0.000)高于高血压组;高血压组Clostridium cluster I(P=0.008,P=0.038)高于高血压合并冠心病组和高血压合并糖尿病组。结论产丁酸菌与老年代谢性疾病的发生发展有一定的相关性,继而为临床微生态制剂的使用提供理论依据。     

莫斯利安发酵乳对人体肠道健康的功效研究

目的 评估莫斯利安发酵乳对促进人体肠道消化吸收及通畅的改善效果;评估莫斯利安发酵乳对人体肠道微生态菌群的改善效果;评估莫斯利安发酵乳对人体肠道短链脂肪酸的改善效果.方法 将符合要求的120名30 ～60岁志愿者根据男∶女=1∶1的比例被随机分为安慰剂对照组、莫斯利安发酵乳组2个组.所有120名志愿者,分别在试验第1～49d服用对应产品,每天2次,分别于上午10点和下午4点服用,每次110 g,持续7周.结果 试验组志愿者的每周排便次数、排便不畅现象、排便时间、排便正常占总排便次数比例有显著改善,志愿者对排便次数、排便时间、粪便性状和排便习惯的满意度增加;试验组志愿者的腹胀、腹痛、胃胀、胃部沉重、食欲不振现象从第1周开始有改善,肠道排气现象增加;试验组志愿者在服用相应试验产品后粪便产气荚膜菌计数有明显下降,乳杆菌计数有明显上升,与自身干预前水平相比差异均有统计学意义（均有P ＜0.05）,且与组0志愿者服用安慰剂后的指标值相比,差异有统计学意义（均有P＜0.05）;试验组志愿者经产品干预,肠道乙酸、丙酸、丁酸含量以及短链脂肪酸总含量均有显著上升;组0志愿者干预前后肠道乙酸、丙酸、丁酸含量以及短链脂肪酸总含量无明显变化.结论 光明莫斯利安发酵乳对促进肠道消化吸收和通畅,以及对调节志愿者肠道菌群和短链脂肪酸含量有显著作用.     

硼对鸡肉铜铁锌锰含量的影响

目的 :探讨硼对鸡肉铜、铁、锌、锰含量的影响。方法 :选择 1日龄固始鸡 30 0羽 ,随机分成 4个组 ,分别在饮水中添加硼 (以硼酸作为硼源 ) 0、10 0、2 0 0和 4 0 0mg/L。测定 2 1、2 8、35和 4 2日龄时鸡肉中的铜、铁、锌、锰含量。结果 :各组鸡肉铜含量在 0 5 2～ 0 74 μg/g(湿重 )之间 ;锰含量在 0 31～ 0 4 6 μg/ g(湿重 )之间 ;日龄和组间差异均不显著 (P >0 .0 5 ) ;鸡肉铁含量在 6 2 3～ 10 4 1μg/ g(湿重 )之间 ,锌含量在 9 98～ 19 76 μg/ g(湿重 )之间 ,两者均于第 35和 4 2日龄时显著高于对照组 (P <0 0 5 )。结论 :说明硼对鸡肉中铜、锰含量没有影响 ,适量的硼 (10 0mg/L)能显著提高鸡肉中铁和锌的含量。     

益生菌对重症感染性肺炎病儿血糖的稳定作用及其机制研究

目的:探讨益生菌对重症感染性肺炎病儿血糖水平的调节及作用机制。方法:前瞻性纳入重症感染性肺炎病儿80例,随机分为两组,对照组给予常规治疗,治疗组采用常规治疗加用益生菌。两组病儿分别于入组当天和治疗第8天监测血糖浓度,并测定血浆硫化氢(H2S)、D-乳酸以及粪便短链脂肪酸(乙酸、丙酸、正丁酸)水平,同时观察两组病儿的血糖变化、波动情况和预后,并进行分析。结果:两组病儿入组当天的各项指标均无显著性差异(P0.05)。治疗第8天时,治疗组病儿血浆H2S浓度和粪便中乙酸、正丁酸水平明显高于对照组(P0.05);同时,治疗组病儿血浆D-乳酸浓度也较对照组明显降低(P0.05)。治疗第8天,治疗组病儿的血糖水平和高波动比例显著低于对照组(32.5%)(P0.05)。治疗组病儿的临床治愈率也明显高于对照组。而且血糖浓度与H2S、乙酸水平呈明显负相关,与D-乳酸浓度呈显著正相关(P0.05)。结论:重症感染性肺炎病儿应用益生菌可调整肠道菌群结构,加强肠道屏障功能,增加血浆H2S的浓度,调节和稳定血糖水平,并改善临床预后。     

抗性淀粉对大鼠肠道菌群的影响

目的观察抗性淀粉(RS)及其不同类型的摄入对大鼠肠道常见菌群的影响。方法将32只大鼠按体重随机分为4组,每组8只,分别喂以不含RS的饲料、含6%二型抗性淀粉(RS2)、含12%RS2和含6%三型抗性淀粉(RS3)饲料4周。收集大鼠实验前后的粪便,检测其pH值和5种常见菌群(大肠杆菌、拟杆菌、肠球菌、双歧杆菌、乳杆菌)的分布。饲养4周后,处死大鼠取其盲肠内容物,检测其pH值和短链脂肪酸(SCFA)的含量。结果RS2和RS3均可明显增加大鼠粪便中双歧杆菌菌落数(P<005),显著减少肠球菌落数(P<005);盲肠内容物的SCFA随RS2摄入增加而增加,12%RS2组显著高于对照组(P<001),也高于6%RS2组(P<005);RS可降低大鼠盲肠内容物和粪便的pH值(P<005),降低效果随RS摄入量增加而加大,且RS3组优于RS2组(P<005)。结论抗性淀粉可明显改善机体的肠道菌群,并增加其酵解产物SCFA,降低肠道pH值,从而发挥对机体的健康作用。     

Soyoligosaccharide increases fecal bifidobacteria counts, short-chain fatty acids, and fecal lipid concentrations in young Korean women

The effects of soyoligosaccharide intake on human fecal characteristics were investigated by measuring the fecal water content, bifidobacteria counts, pH, and concentrations of short-chain fatty acids (SCFAs) and lipids. Sixteen young women were randomly assigned to one of two groups: (1) 1.5 g/day soyoligosaccharide intake group [low soyoligosaccharide (LSO)] or (2) 3 g/day soyoligosaccharide intake group [high soyoligosaccharide (HSO)]. The experimental period was 30 days, and fecal samples were collected every 7 days. The number of bifidobacteria in feces was increased significantly in the HSO group. Of the fecal SCFAs, propionate and butyrate concentrations were significantly increased in the HSO group. The excretions of total lipids in feces were significantly increased in both the LSO and HSO groups. These results demonstrate that a soyoligosaccharide intake of 3 g/day increases fecal bifidobacteria counts, SCFA concentrations, and fecal lipid output in Korean young women.     

Relationships between transit time in man and in vitro fermentation of dietary fiber by fecal bacteria

OBJECTIVE: To assess the effects of drug-induced changes in mean transit time (MTT) on the activity of human fecal flora in vitro. METHODS: The activity of fecal flora was estimated by the ability of a fecal inoculum to ferment a substrate (beet fiber) in vitro in a batch system for 24 h. The inoculum was collected from 8 healthy volunteers studied during three 3-week randomized periods, who received a controlled diet alone (control period) or the same diet with either cisapride or loperamide. Cisapride and loperamide were adjusted in order to halve and double MTT measured during the control period. At the end of each period, the percentage disappearance of the initial added substrate and the concentration and the profile of short-chain fatty acids (SCFAs), were determined. RESULTS: In the control period, the pH of the inoculum and SCFA concentration were inversely related to MTT (P=0.0001). Individual SCFA production was also significantly related to MTT (P<0.01). Cisapride-reduced transit time was associated with a significant rise in the concentrations of total SCFAs (P<0.05), propionic and butyric acids (P<0.05) and the percentage substrate disappearance (P<0.05). Inverse relations were observed during the loperamide period. Moreover, MTT was inversely related to the percentage substrate disappearance (P<0.001), SCFA production (P<0.001) and butyrate production (P<0.0005). CONCLUSION: Changes in MTT alter bacterial activity and modify the bacterial pathways affecting the proportion of individual SCFAs. European Journal of Clinical Nutrition (2000) 54, 603-609     

Effects of Different Concentrations of Ganpu Tea on Fecal Microbiota and Short Chain Fatty Acids in Mice

Ganpu tea is composed of tangerine peel and Pu-erh tea. Current research suggests that both products can interact with gut microbes and thus affect health. However, as a kind of compound health food, little information is available about the effect of Ganpu tea on intestinal microorganisms. In this study, the basic physiological parameters (body weight, white adipose tissue and serum fat), the regulation of intestinal microorganisms and content of short-chain fatty acids (SCFAs) in feces of healthy mice were studied. The Ganpu tea can reduce the weight gain of mice and the increase in white adipose tissue (p < 0.01). After the intake of Ganpu tea, the abundance of Bacteroidetes increased (p < 0.05), whereas that of Firmicutes decreased (p < 0.01), indicating the latent capacity of Ganpu tea in adjusting the gut microbiota. Moreover, Ganpu tea differentially affected the content of different types of SCFAs in feces. Ganpu tea at the lowest concentrations showed positive effects on the concentrations of SCFAs such as acetic acid and propionic acid, whereas the concentration of butyric acid was decreased. For branched short-chain fatty acids (BSCFAs) such as isobutyric acid, isovaleric acid, etc., Ganpu tea reduced their concentrations. Our results indicated that Ganpu tea may have positive effects on preventing obesity in humans, but further research is needed before introducing such dietary therapy.     

Influences of dietary adaptation and source of resistant starch on short-chain fatty acids in the hindgut of rats

The effect of adaptation time on the concentration and pattern of short-chain fatty acids (SCFA) formed in the hindgut of rats given resistant starch (RS) in the form of raw potato starch (RPS) or high-amylose maize starch (HAS) was evaluated. Each starchy material was tested in diets containing 100 g indigestible carbohydrates/kg DM, and fed for 13, 28 and 42 d. At the end of each period, the content of SCFA was determined in caecum, distal colon and faeces. The caecal concentration of total and individual SCFA increased for both diets with increasing adaptation time. The concentration of butyric acid was higher in the group fed RPS than in that fed HAS at all adaptation times. The caecal proportion of butyric acid was low both in rats fed RPS and HAS (6 and 4 %, respectively) following 13 d of adaptation. However, after 28 d of adaptation, the proportion of butyric acid had increased to 19 % in rats given RPS. A longer adaptation period (42 d) did not increase the proportion of butyric acid further. With HAS, there was also a significant (P<0.01) increase in the proportion of butyric acid with longer adaptation time. However, the increase was much slower and the proportion of butyric acid reached 6 and 8 % after 28 and 42 d respectively. It is concluded that the pattern of SCFA formed from RS in rats is dependent on adaptation time. It cannot be excluded that the different patterns of SCFA reported in the literature for RS may be due to the time of adaptation.     

Fiber from a regular diet is directly associated with fecal short-chain fatty acid concentrations in the elderly

It has recently been suggested that fiber exerts a considerable effect on microbiota composition and on fecal short-chain fatty acid (SCFA) production, the concentration of which in the colon is important for immune regulation and for maintaining gut and overall health. To test the hypothesis that the fiber consumed in a regular diet affects fecal SCFA concentrations in the elderly, the authors investigated the association between different types of fiber intake and fecal SCFA concentrations in 32 institutionalized elderly subjects aged between 76 and 95 years. Food intake was recorded by means of a validated food frequency questionnaire. Total, soluble (pectin and hemicellulose) and insoluble (pectin, hemicellulose, Klason lignin, and cellulose) fiber was determined using Marlett Food Composition Tables. Analysis of acetic, propionic, and butyric acid concentrations was performed using gas chromatography–mass spectrometry. Potato intake was directly associated with SCFA concentrations and apple intake with propionate concentration. Of the fibers, cellulose showed an independent association with acetate and butyrate concentrations, and insoluble pectin explained a part of the variation in propionate. In conclusion, our results provide further evidence regarding the relation between diet and SCFA concentration in the elderly. The identification of an association between the regular intake of foods such as potatoes and the production of SCFAs provides an opportunity to improve public health.