不同区段小鼠小肠类器官体外培养方法建立

肠道是食物营养物质消化吸收的主要器官,良好的肠道体外培养模型有助于推动新型食物营养物质及功能活性物质的吸收及功效评价方法建立.本文以含有肠道干细胞的肠道隐窝为基础,通过优化不同区段小肠隐窝分离方法和体外培养基组成,建立一套完整的不同区段小肠类器官(包括十二指肠、空肠和回肠)培养方法.采用免疫荧光和RT-PCR方法进一步...     

肠道黏膜免疫屏障及其菌群与机体健康关系的研究进展

肠黏膜屏障对于防止肠腔内细菌、食物抗原、酶和化学药物等直接与黏膜裸露面接触而引起疾病至关重要,其免疫屏障对机体的健康作用越来越被人们重视.黏膜免疫系统不仅具有一般性的屏障作用,而且还参与体液免疫和细胞免疫过程,在机体肠道内环境的调节中起重要作用.随着更深入的研究,人们可能会找到新的维持机体健康的途径.本文对肠道黏膜免疫调控机理、肠道菌群及营养物质对肠黏膜屏障功能的影响,以及肠黏膜屏障受损对机体健康的危害等方面进行了综述.     

饮食、肠道微生物与健康的关系研究进展

肠道微生物是膳食与人体健康的桥梁,与营养物质的吸收和代谢密切相关,是人体重要的“微生物器官”。同时,研究学者们也已经清楚地认识到这个重要的“微生物器官”与人体生理功能、健康和疾病关系密切,对人体的重要性不容忽视。为此,本文就近几年来有关膳食对肠道微生物结构以及代谢产物影响的研究进行综述,并介绍肠道微生物与人体生理功能及健康的关系,旨在为未来研究饮食、肠道微生物与健康的关系提供参考。     

外翻肠囊法考察复合红花籽油的肠吸收特性

该研究旨在初步考察复合红花籽油的肠吸收特性。采用外翻肠囊法对其肠吸收部位、时间、给药浓度进行研究,通过气相色谱-质谱法（GC-MS）测定肠收集液中亚油酸（Linoleic Acid,LA）及α-亚麻酸（α-Linolenic Acid,ALA）含量,通过计算吸收转运参数、吸收速率参数分析其肠道转运机制。不同肠段中,其主要成分LA与ALA均能在十二指肠（LA:2.71 mg;ALA:1.60 mg）与空肠（LA:1.89 mg;ALA:1.43 mg）中被检出,通过计算不同部位透过药量（M）、药物吸收转化率（A）和药物剩余百分数（R）,结果显示十二指肠段中LA、ALA的M高于空肠段,A与空肠段接近,R低于空肠段,因此十二指肠为最佳吸收肠段。在120 min时,LA和ALA的Pappi（瞬时表观渗透系数）皆高于其他时间点,因此最佳吸收转运时间为120 min。在给药倍数为2.0倍时,肠囊液中的LA和ALA浓度最高,分别为0.35、0.19 mg/mL,因此最佳给药浓度为200 mg/mL。结果表明复合红花籽油的肠吸收特性可能为具有时间与浓度依赖性的被动运输模式且在十二指肠段中单向转运。     

色氨酸对肠道屏障功能的影响

肠道作为动物机体最重要的组织器官,一方面负责膳食营养物质的消化吸收;另一方面发挥重要的屏障功能。氨基酸对肠道屏障功能、肠道发育以及细胞增殖具有重要的作用,然而色氨酸对肠道屏障及其紧密连接蛋白的作用以及机制还未揭示。本实验选取健康的生长肥育猪,根据体重随机分为2个组:对照组和0.2%Trp添加组。对其生长性能、器官指数、血液生化指标、肠道粘膜形态、肠道通透性及紧密连接蛋白基因进行了分析。实验表明,色氨酸增加了生长肥育猪的平均日采食量和血清中二胺氧化酶的活性,并降低了空肠紧密连接蛋白occludin和回肠claudin-1 m RNA的表达。因此,膳食色氨酸在一定程度上增加生长肥育猪肠道通透性。     

双歧杆菌调理和改善肠道相关疾病作用的研究进展

双歧杆菌(Bifidobacterium)作为人体肠道中具有代表性的一大类益生菌,因其具有营养、抗菌、免疫调节、抗癌及抗肿瘤等多种生理功能,一直是研究者们的热门研究内容。肠道相关的疾病主要包括:炎症性肠病(IBD)、肠易激综合征(IBS)、腹泻、结肠癌、直肠癌等,目前这些肠道相关性疾病的发生、发展机理不是很清楚,而传统的药物治疗效果并不令人满意,且副作用大。本文主要就双歧杆菌的生理功能及双歧杆菌制剂在调理和改善肠道相关疾病的国内外研究进展进行综述。     

脑-肠轴与精神疾病肠道微生物的研究进展

人体肠道拥有大量且种类丰富的微生物群,在机体的多项生理过程中扮演着重要的角色。近年来越来越多的研究表明,肠道菌群可以通过脑-肠轴来调节机体大脑的发育和行为,从而对自闭症谱系障碍、精神分裂症、抑郁症、焦虑症等精神类疾病具有良好的防治作用。本文在阐述脑-肠轴的双向调控机制基础上,总结了与各种精神疾病直接相关因素的变化和可能机制,并进一步归纳了近年来国内外关于各类精神疾病中肠道微生物改变的研究进展,以期为上述精神类疾病患者通过早期益生菌干预治疗的研究提供新的思路和理论参考。     

双歧杆菌，让你的肠道年轻起来

肠道是身体中最劳累的器官之一,它每天要为全身所有的营养物质分化、吸收、排解、平衡等忙碌不停,稍有不慎,细胞的营养就会缺失或不足,我们的身体就会出现毛病。     

类胡萝卜素肠道吸收与代谢的影响因素研究进展

类胡萝卜素是类异戊二烯单元组成的一类萜类色素,在维持眼部健康、提高免疫力等方面具有重要作用。人体不能合成这种色素,必须从膳食中摄取。人体摄入后,类胡萝卜素会经历复杂的消化吸收与代谢过程,并受到食物本身以及人体内环境等多种因素的影响。肠道是类胡萝卜素吸收、代谢最重要的场所。本文综述化合物结构、膳食因子、加工方式、包埋、转运蛋白、生物裂解酶等因素对类胡萝卜素在肠道吸收、代谢的影响,并探讨肠道菌群在其中发挥的作用,为类胡萝卜素体内的吸收与生物转化研究提供参考。     

微生态制剂对动物肠道健康影响的研究进展

动物肠道是进行消化和吸收营养物质的主要部位,肠道中有大量复杂多样的微生物通过或者定殖,对维持胃肠系统的动态平衡发挥着至关重要的作用,肠道微生物及其代谢对动物机体生理健康发挥着关键性影响和调控作用。微生态制剂是一种安全、高效的生物类饲料原料,通过调节宿主体内的微生态结构,从而增强动物机体免疫力,促进动物生长和提高饲料转化率等。综述了近几年微生态制剂对动物肠道健康影响等方面的研究概况,以期为微生态制剂在畜产业生产上的合理应用提供参考。     

膳食脂质肠道消化及吸收的研究进展

膳食脂质作为人类生活中一种必不可少的营养物质来源，为机体提供所需的必需脂肪酸和能量，维持人体正常的生理活动，其中肠道作为脂质最主要的消化场所及特定吸收场所，发挥了重要的作用。该研究在基于脂质肠道消化途径的基础上，从脂质自身形态、蛋白质与脂质相互作用下的形态、脂质构型变化、胆汁盐分泌、胰脂肪酶以及共脂肪酶等多角度论述了影响脂质肠道消化的主要因素，分析了影响脂质消化关键行为的界面作用，从转运因子调节、分子吸收路径以及肠道微生物间接调控吸收三个方面阐述了膳食脂质的肠道吸收机制，为深入开展膳食脂质的功能化修饰、高值化利用、创新性研发提供了理论依据。     

Lactose--a potential dietary fiber. The regulation of its microecological effect in the intestinal tract. 1. Problems, state of knowledge and methods]

Food components of different chemical structure which attain the colon without being attacked by digestion and absorption during their transit through the small intestine are defined as dietary fibre. In the colon they serve as energy or nutrient source for the intestinal microflora or are excreted without change. Not only chemical structure is decisive when a food component has to be assigned to either nutrients or dietary fibre: Substances resisting small intestine digestion due to the lack of corresponding catabolizing enzymes in man are supposed to be "obligate" dietary fibre. "Potential" dietary fibre are nutrients which are only partially digested in the small intestine. Lactose--the main carbohydrate of milk--represents a typical potential dietary fibre. The present paper investigates the factors being responsible for both the degree of lactose utilization in the small intestine and its efficiency in the colon.     

Dissolution tests as a tool for predicting bioaccessibility of nutrients during digestion

Bioaccessibility and bioavailability of active ingredients (like vitamins, antioxidants, etc.) into food systems is often compromised by factors like low permeability and/or solubility within the gut, lack of stability during food processing (temperature and oxygen) as well as in the gastrointestinal tract (pH, enzymes, presence of other nutrients). Moreover, little is known on the influence of food structure and breakdown in the gut on nutrient release. The possibility of predicting the release of nutrients from food matrices under simulated gastrointestinal conditions is of great relevance in order to define which food matrix is best for which nutrient, as well as for looking at the interaction of ingredients with the enzymes involved in the digestive process. This study explores the potential relevance of dissolution tests as a tool for predicting bioaccessibility of nutrients during in vitro digestion. Whey protein hydrogels containing green tea extract (GTE) were chosen for this study. Different simulated in vitro gastrointestinal conditions (GI) were applied throughout the dissolution experiments and the GTE was analysed by UV–vis absorption spectroscopy. It was possible to distinguish between two different release kinetics when experiments were performed in simulated gastric or intestinal media. In the gastric step, the kinetic of GTE release was lower than in an intestinal environment, suggesting that more GTE is released and available for absorption into the intestine than in the stomach. The present study shows that it is possible to use the dissolution tester as a screening method to mimic nutrient release from a food matrix in the gastrointestinal tract.     

An integrated look at the effect of structure on nutrient bioavailability in plant foods

The true bioavailability of a nutrient being intrinsically coupled to the specific food matrix in which it occurs remains poorly considered in nutrition science. During digestion, the food matrix and, in particular, the structure of food modulate the extent and kinetics to which nutrients and bioactive compounds make themselves available for absorption. In this perspective, we describe an integrated look at the effect of structure on nutrient bioavailability in plant foods. Based on this integrated look, cell wall integrity and the particle size of the plant material during its transit in the small intestine determine the bioavailability of plant nutrients; in turn, cell wall integrity and particle size are determined by the level of oral processing and, accordingly, what subsequently escapes digestion in the upper intestine and is utilized by colon microbiota. Ultimately, the effect on nutrient digestion is linked to food structure through each step of digestion. A consideration of the structure rather than just the composition of foods opens up possibilities for the design of healthier foods. © 2018 Society of Chemical Industry     

Symposium review: Re-evaluation of National Research Council energy estimates in calf starters

Provision of nutrients in appropriate amounts to meet nutrient requirements for growth, production, and reproduction is the basis for modern animal nutrition. Ration formulation systems predict nutrient requirements based on numerous inputs and then predict nutrient supply based on predicted intake and nutrient content of feeds. Energy systems are used to predict energy supply based on gross caloric content of feeds followed by adjustments for digestion and metabolism of ingested energy. Many models of energy supply use static coefficients of digestibility based on nutrient composition of feed. Other models partition digestion dynamically between ruminal and postruminal digestion but use static estimates of intestinal digestibility to predict energy supplied to the animal. In young calves, both ruminal fermentation and intestinal digestion are underdeveloped; therefore, existing models of energy supply might overestimate the energy available before complete gastrointestinal maturation. In a series of experiments, we reported that total-tract digestion of nutrients changes with advancing age and nutrient intake. Total-tract digestion was measured in calves from 3 to 16 wk of age when fed different amounts and types of milk replacers. Calves were also fed different types of calf starter for ad libitum consumption. Total-tract digestibility of protein, fat, neutral detergent fiber, and nonfiber carbohydrate (NFC) was used to calculate the metabolizable energy (ME) in starter. We used nonlinear regression to estimate the contribution of protein and fat from starter and milk replacer before weaning. Early in life, calculated ME of starter was low and increased with increasing intake of NFC. Cumulative intake of NFC was more highly correlated with changing ME values than other indices, including age, intake of milk replacer, or intake of other nutrients in starter. When calves consumed at least of 15 kg of NFC, ME calculated from digestibility measurements was similar to the ME calculated using National Research Council equations and indicated maturation of gastrointestinal digestion. Our data suggest that intake of NFC is critical to gastrointestinal maturation and the calf's ability to extract energy from calf starter.     

油脂营养成分及其对肠道健康影响的研究进展北大核心CSCD

油脂是人体最主要的营养物质之一,其消化吸收主要发生在肠道,而肠道内存在种类繁多的菌群,可以直接参与人体的消化吸收、脂质代谢、能量供应等。油脂的消化吸收可能与多种代谢紊乱和肠道疾病、糖尿病、肥胖等慢性疾病存在联系,而食用油脂摄入不平衡会影响肠道菌群组成和代谢,破坏肠道稳态,进而可能导致上述疾病的发生。综述了油脂的脂肪酸组成、功能性伴随成分及其对人体健康的影响,分析了近年来油脂对肠道菌群组成及其代谢产物影响的研究,并对未来的研究方向进行了展望,这对进一步开展油脂营养特性及其对肠道健康影响的研究以及合理膳食保障人体健康具有积极意义。     

五味调与营养平衡及其信号传导

“五味调”是中国餐和烹饪的基本理论和原则。一直以来,很多人认为中国餐虽然讲究色、香、味,但是不讲究营养,而有关味觉和嗅觉受体与相应的配体相互作用研究表明,味觉和嗅觉所传感的正是机体所需要的营养成分,并构成营养体内平衡的分子结构识别机制和生理调节与代谢基础,五味调和在机体生命活动和营养体内平衡中具有重要作用。味觉和嗅觉受体以G蛋白偶联受体超家族为主体,构成机体对营养物质的结构与功能、定量与定性的传感系统。该传感系统不仅分布在舌和鼻咽部的味蕾处,而且遍布整个消化道系统,以及神经信号传导系统,在外周系统和大脑之间构建起通讯联系和“编码系统”。大量研究表明,在漫长的进化中,人和动物已经形成了一个从看到食物开始,一直到食入、咀嚼、消化、吸收、排泄等各个关键环节的时序控制及其复杂的信号级联激活和传递系统。机体通过味觉和嗅觉系统从饮食的形态、质构到分子结构与功能等进行严格的识别和筛选,系统地控制各种营养成分的消化和吸收,并同时以严格的时序性信号传递与级联,从神经信号的快速传递到神经和体液混合传递,再到体液传递相互配合,构成食品营养与安全的交响乐式的信号传递与控制过程,决定了机体的营养吸收、防御、体内平衡、生理活动、代谢与健康。本文在综述这些进展的基础上提出：五味调和是健康饮食的基础,通过味觉和嗅觉受体及其与配体的相互作用的研究,不仅可以为嗅觉和味觉测定开辟新的方法和途径,而且为调味品的研究和健康饮食,控制现代文明病的发生和发展提供科学依据。     

Use of brush border membrane vesicles to simulate the human intestinal digestion

The intestine presides over a series of vital functions in the human body, among which the digestion/absorption of nutrients. Despite their major digestion role, the impact of the enzymes of the luminal intestinal surface on food components has been considered in relatively few experiments of simulated gastrointestinal digestion. In contrast, the identification of proteolitically stable peptides which survived digestion in multiphasal models that also included a step with small intestinal brush border membrane (BBM) peptidases has provided physiologically consistent results. Herein, we critically review the use of BBM enzymes to simulate the intestinal digestion of dietary polypeptides. Addressing the controversial issue of the in vitro–in vivo correspondence of the digestion models, the review emphasizes the need to establish consensus protocols to simulate the intestinal step, for instance using the BBM hydrolases at least in a selected number of cases. The factors that have limited the development of relevant models of intestinal degradation are discussed together with hints to possible alternatives, forthcoming approaches and future perspectives to reproduce the physiopathology of the human small intestine.     

杂粮营养物体内和体外消化研究现状及其产物的功能性

杂粮富含淀粉、蛋白质、纤维素和酚类等营养物质,是主粮膳食的有益补充,其营养物质的消化研究有助于杂粮食品的研发和应用。本文首先概括了杂粮与主粮的营养物特点与消化差异,其次综述了杂粮体内和体外宏量和痕量营养物的消化与功能成分的研究进展,旨在为运用体内外消化方法模拟杂粮中营养物质的消化吸收提供参考。