低聚糖对婴儿肠道菌群的益生功能

发布时间：2018-08-10 18:29

【摘要】：自二十世纪七十年代,随着科学家对膳食纤维的研究不断深入,人们对可溶性膳食纤维低聚糖的兴趣日益增加。对于婴幼儿来说,母乳喂养作为最好的喂养方式被给予极高评价和推广,母乳中除多种营养物质外,富含百余种低聚糖,对婴儿肠道营养素的吸收、大便次数及形状的改变起着重要的作用。当母乳喂养不能满足婴儿需求的时候,母乳替代品即婴儿配方奶粉就起到必不可少的作用。研究发现母乳喂养的婴儿粪便中双歧杆菌和乳酸杆菌占优势,人工喂养的婴儿粪便中则以大肠埃希菌、肠球菌为优势,双歧杆菌等益生菌建立相对延迟。这是由于母乳中含有可以促进双歧杆菌等益生菌菌群生长的低聚糖,是目前无法体外合成的复杂生长因子。因此,向母乳替代品中添加具有母乳低聚糖生物功能的营养物质成为重要的研究方向。临床上,广谱抗生素的使用也会对婴儿体内固有的肠道菌群造成刺激,从而可能打破肠道菌群原有的平衡,引起婴儿消化不良甚至导致肠道感染等疾病。低聚糖对机体肠道菌群的平衡具有良好的调节作用。本研究采集完全母乳喂养婴儿的粪便进行相应分析,主要测定了粪便中的水分含量和脂肪酸含量,说明了以母乳喂养的婴儿代谢物中含有较高的持水物质,并且含有一定量不易消化的脂肪酸。利用婴儿粪便中的菌群对分别添加低聚果糖和低聚半乳糖作为碳源的培养基进行体外发酵实验,结果表明,俩种低聚糖均能被双歧杆菌和乳酸菌所利用,主要代谢产物是乳酸、乙酸和丙酸。而实验中未添加低聚糖的俩个对照组中双歧杆菌和乳酸菌的数量增加较实验组变化幅度较小。本文利用小鼠动物实验评价了低聚糖对抗生素性肠道菌群失衡的调节作用。四周大昆明小鼠实验前,采用自由饮用盐酸克林霉素蔗糖溶液(2.8mg/mL)5天的方法造成小鼠肠道菌群失衡的模型。再将低聚果糖和低聚半乳糖制成1：1的混合溶液对肠道菌群失衡模型的小鼠灌胃,使用平板计数法对小鼠粪便优势菌群进行选择性培养分析,发现低聚糖能有效促进肠道益生菌双歧杆菌和乳酸菌的数量增加,评价了低聚糖混合溶液对小鼠肠道菌群失衡模型的调节作用,并初步确定其发挥作用的有效剂量。实验具体结果如下： (1)通过对婴儿粪便的水分含量的测定,发现母乳喂养婴儿粪便中的水分含量比较高,达到83.79%。由于母乳喂养婴儿的肠道菌群健康平衡,大量益生菌代谢产生的脂肪酸的种类较多,主要多为中长链脂肪酸。 (2)通过对婴儿粪便菌群的体外发酵实验,表明低聚果糖和低聚半乳糖对婴儿肠道中双歧杆菌和乳酸菌有促进生长繁殖的作用,低聚糖经过肠道益生菌代谢产生的短链脂肪酸主要包括乳酸、乙酸和丙酸等,这些脂肪酸可以改变肠道环境,调节肠道pH值。 (3)动物实验中,小鼠灌胃低聚糖溶液后,肠道各菌群的数量均恢复到正常水平,说明低聚糖对小鼠抗生素性肠道菌群失衡具有一定的调节作用。这种调节作用的原因可能是小鼠肠道益生菌利用低聚糖代谢产生的短链脂肪酸改变了肠道环境,并抑制了肠球菌和肠杆菌等有害菌的增殖。以上结果表明,低聚果糖和低聚半乳糖均具有增加肠道厌氧菌数量,促进双歧杆菌、乳酸菌的生长繁殖,并抑制肠杆菌等条件致病菌繁殖的作用。俩种低聚糖的混合溶液对小鼠抗生素性肠道菌群失衡有良好的调节作用。综合上述结果,可以初步确定低聚果糖和低聚半乳糖均适合添加到婴儿食品中,可以防止婴儿便秘,维持肠道益生菌的优势地位,保护婴儿肠道环境正常生长。
[Abstract]:Since the 1970s, with the deepening of research on dietary fiber by scientists, people are increasingly interested in soluble dietary fiber oligosaccharides. For infants and young children, breastfeeding as the best way of feeding has been highly valued and promoted. Breast milk is rich in more than 100 kinds of oligosaccharides, in addition to a variety of nutrients, for infants. The absorption of intestinal nutrients, the change of stool frequency and shape play an important role.
When breast-feeding fails to meet the needs of infants, breast milk substitutes, i.e. infant formula, play an essential role. Studies have found that bifidobacteria and Lactobacillus predominate in feces of breast-fed infants, while probiotics such as Escherichia coli, Enterococcus, and Bifidobacteria predominate in feces of artificially fed infants. This is because breast milk contains oligosaccharides that promote the growth of probiotic bacteria such as bifidobacteria, which are complex growth factors that can not be synthesized in vitro.
Clinically, the use of broad-spectrum antibiotics can also stimulate the intestinal flora inherent in infants, which may break the original balance of intestinal flora, cause infantile dyspepsia and even cause intestinal infections. Oligosaccharides have a good regulatory effect on the balance of intestinal flora.
The feces of breast-fed infants were collected and analyzed in this study. The water content and fatty acid content in the feces were determined. The results showed that the metabolites of breast-fed infants contained high water-holding substances and a certain amount of non-digestible fatty acids. The results showed that both oligosaccharides could be utilized by bifidobacteria and lactobacillus. The main metabolites were lactic acid, acetic acid and propionic acid. Smaller.
The effects of oligosaccharides on the imbalance of intestinal flora induced by antibiotics were evaluated in mice. The imbalance model of intestinal flora in mice was established by free drinking of clindamycin hydrochloride sucrose solution (2.8mg/mL) for 5 days before the experiment in Kunming mice. The results showed that oligosaccharides could effectively increase the number of intestinal probiotics bifidobacteria and lactic acid bacteria. The regulating effect of oligosaccharides mixed solution on intestinal flora imbalance model in mice was evaluated and preliminarily confirmed. The effective dose that determines its function.
The results are as follows:
(1) Through the determination of water content in infant feces, it was found that the water content in the feces of breast-fed infants was relatively high, reaching 83.79%. Due to the healthy balance of intestinal flora in breast-fed infants, a large number of probiotics metabolized fatty acids, mainly long-chain fatty acids.
(2) Fermentation experiments in vitro showed that fructooligosaccharides and galacto-oligosaccharides could promote the growth and reproduction of bifidobacteria and lactic acid bacteria in the intestinal tract of infants. Short-chain fatty acids produced by oligosaccharides metabolized by intestinal probiotics mainly included lactic acid, acetic acid and propionic acid, which could change the intestinal environment. Regulate intestinal pH.
(3) In animal experiment, the number of intestinal flora returned to normal level after administration of oligosaccharide solution in mice, indicating that oligosaccharide could regulate the imbalance of intestinal flora induced by antibiotics in mice, which may be due to the alteration of intestinal flora by short-chain fatty acids produced by intestinal probiotics through oligosaccharide metabolism. Environment, and inhibit the proliferation of Enterococcus and Enterobacteriaceae.
The above results showed that fructooligosaccharides and galacto-oligosaccharides could increase the number of anaerobic bacteria in intestine, promote the growth and reproduction of bifidobacteria and lactic acid bacteria, and inhibit the reproduction of conditional pathogenic bacteria such as Enterobacter. In order to preliminarily determine that fructooligosaccharides and galacto-oligosaccharides are suitable for infant food, can prevent infant constipation, maintain the dominant position of intestinal probiotics, protect the normal growth of infant intestinal environment.
【学位授予单位】：东北农业大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R151

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