肠道菌群与婴幼儿食物过敏相关性的研究进展

随着婴幼儿食物过敏的发病率逐年上升,食物过敏逐渐成为了全球性公共卫生问题。大量研究表明人体内肠道菌群与食物过敏有着密切的关系,在受到外界因素的干扰后,肠道菌群多样性和数量发生改变,进而引发机体对某些正常抗原的免疫耐受度降低,导致过敏反应。本文介绍了食物过敏婴幼儿和健康婴幼儿肠道菌群的差别,对肠道菌群在食物过敏中的调节机制(影响肠道细胞功能和调节屏障保护特性、产生信号分子进行免疫调控以及促进和维护机体口服耐受)进行综述,并对肠道菌群调节婴幼儿食物过敏的策略进行展望。     

Growth and health of Holstein calves fed milk replacers supplemented with antibiotics or Enteroguard

Forty-five Holstein calves were fed milk replacers containing either antibiotics [MRA (oxytetracycline at 138 mg/kg and neomycin at 276 mg/kg), n = 22)] or Enteroguard [MRE, a blend of fructooligosaccharides, allicin, and gut-active microbes at (129 mg/kg, n = 23)] from birth to 5 wk of age to compare effects on average daily gain and on incidence of scours. Performance was evaluated by measuring weight gain, feed efficiency, and fecal scores. The overall body weight gains and severity of scours were not different between treatments, nor were there differences in starter intake or mean body weight gain. During wk 2, the average gain of calves fed MRA was less than that of calves fed MRE (0.07 vs. 0.09 kg/d, P = 0.09), and greater during wk 5 (0.62 vs. 0.51 kg/d, P < 0.01); however, total gain for calves fed MRE was not different from calves fed MRA. Likewise, average feed efficiencies (gain/dry matter intake) were not different. Severity of scours, as measured by fecal scores, and concentrations of serum proteins, an indirect measure of immunoglobulins, were similar for calves fed MRA and MRE. The results suggest that antibiotics in milk replacers can be replaced with compounds such as fructooligosaccharides, probiotics, and allicin to obtain similar calf performance.     

Evolutionary concepts in the functional biotics arena: a mini-review

Over the years, the attempts to elucidate the role of beneficial microorganisms in shaping human health are becoming fairly apparent. The functional impact conferred by such microbes is not only transmitted by viable cells or their metabolites but also through non-viable cells. Extensive research to unveil the protective action of such wonder bugs has resulted in categorizing the beneficial microflora and their bioactive metabolites into a variety of functional biotic concepts based on their intended applications in various forms. In the modern era, these are often termed as probiotics, prebiotics, synbiotics, postbiotics, next-generation probiotics, psychobiotics, oncobiotics, pharmabiotics, and metabiotics. Currently, the concept of traditional probiotics is being widened to include microbes beyond lactic acid bacteria. Indeed, this diversification has broadened the functional food portfolio from food to pharmaceuticals. In this context, the present review aims to summarize the existing biotic concepts and their differences thereof.     

益生菌保健酸奶发酵剂配制和益生素对菌体数量影响的研究

本文研究了在不同的益生菌发酵剂配比条件下酸奶制品的质地和综合口感.双歧杆菌保加利亚乳杆菌噬热链球菌为411;分别制作发酵种子用于酸奶的生产,可以使双歧杆菌活菌数达到4.9x107 cfu/ml.采用添加菊粉、大豆低聚糖和低聚果糖等益生素,可以促进双歧杆菌的活菌数目提高.     

益生菌及其在食品中应用进展

益生菌能够促进人体健康，在食品工业中有广泛的应用。该文综述了益生菌的概念、国内外研究现状、安全性和必备条件及其在食品加工中的应用。     

益生菌发酵牛初乳对致病菌抑制作用的研究

研究了益生菌发酵牛初乳对致病性大肠杆菌及幽门螺旋杆菌的抑制作用。结果表明,初乳经益生菌发酵,导致初乳pH值降低,初乳IgG活性也相应降低,在pH值为4.6时,IgG活性仅为初乳的25%。不同益生菌发酵初乳在不同pH值对大肠杆菌及幽门螺旋杆菌均有抑制作用,且嗜酸乳杆菌发酵初乳抑制作用最强,对大肠杆菌的抑制率最高达83.2%,对幽门螺旋杆菌抑菌圈直径最大达17.2mm,达到高度敏感,分别较初乳的抑制作用提高47.52%和52.21%。不同益生菌发酵初乳的抑菌作用依次为嗜酸乳杆菌>双歧杆菌>混合乳酸菌>德氏乳杆菌保加利亚亚种>嗜热链球菌。     

乳杆菌和双歧杆菌的生理代谢多样性研究

比较了拥有潜在益生特性的28株乳杆菌(Lactobacillus)和26株双歧杆菌(Bifidobacterium)的生理代谢差异，这些菌株多数来源于波兰。筛选过程当中，首要的指标是检测菌株对低pH值和对胆盐的抗性以及在发酵或非发酵乳制品当中的存活能力。考察了这些候选菌株是否产生某种拮抗物质，同时评价这些物质对来自于食物或肠道内的病原微生物或生产当中不渴望微生物的抑制效果。研究了混合发酵剂中各菌株之间的共生能力，并对它们在生产加工过程中表现出的对诸如冷冻、冻干或储藏等处理的耐受能力进行评价。采用高效液相色谱(HPLC)的方法对菌株利用各种碳源所生成的代谢产物的类型进行了测试。结果表明，所有供试菌株存在很大的生理代谢差异，因而，应选择那些具有科学测定基础的菌株作为益生菌菌株。     

产气荚膜梭菌耐药及防控研究进展

产气荚膜梭菌是一种能够引起人类食物中毒和动物坏死性肠炎的食源性病原,在动物产品生产过程中引发疾病并通过加工环节传播,威胁人类健康,同时给养殖行业带来巨大经济损失。随着耐药问题的日益严峻以及2020年"饲料端全面禁抗"的实施,利用生物防控技术进行产气荚膜梭菌防治将在养殖业中发挥巨大作用。本文针对目前产气荚膜梭菌的耐药特性,详述了产气荚膜梭菌的防控现状,总结了全面的综合防控策略,为产气荚膜梭菌的防控提供参考。     

两株具有潜在益生作用的人源链球菌的安全性评价

对分离于健康儿童口咽部的2株对金黄色葡萄球菌等常见致病菌具有广谱拮抗作用的甲型链球菌菌株1-4和4-2的安全性进行评价,为其作为呼吸道益生菌产品的研发和制备提供安全性依据。通过给予SPF级小鼠口服含有菌株1-4和4-2不同剂量的菌液的急性毒性实验以及耐药性的测定,观察动物是否出现死亡,急性毒性体征,细菌移位生长等情况。未发现动物死亡情况,实验组的体重变化采食量以及脏器指数均与对照组无显著差异,未有细菌移位生长的现象发生。菌株1-4和4-2均对9种常见抗生素的检测结果为敏感,其中菌株4-2对红霉素具有抗性。菌株1-4和4-2的安全性评价初步显示对小鼠无毒副作用,具有良好的安全性,可以作为呼吸道微生态制剂等产品的备用菌株。     

益生菌发酵南瓜浆的研究

该实验研究了瑞士乳杆菌、肠膜明串珠菌、嗜酸乳杆菌和鼠李糖乳杆菌在发酵南瓜浆过程中的生长规律及其内在联系,根据活菌数、产酸速度和感官评价筛选出适合于南瓜浆发酵用的菌株。结果表明,瑞士乳杆菌迟滞期最短,4 h内就处于对数生长期,发酵速度较快;发酵结束时,鼠李糖乳杆菌活菌数最高,达到9.0 lg（CFU/mL）。发酵过程中,活菌数、pH、乳酸含量、还原糖含量变化存在一种对应关系。瑞士乳杆菌和鼠李糖乳杆菌发酵南瓜浆感官评分最高,分别为4.8分、4.6分。综合考虑,瑞士乳杆菌和鼠李糖乳杆菌更适合发酵南瓜浆。