乳酸菌抗幽门螺旋杆菌感染的研究进展

综述了近年来对乳酸菌抗幽门螺旋杆菌感染的研究进展,内容包括乳酸菌抗幽门螺旋杆菌感染的机制及应用、乳酸菌抗原递送载体、乳酸菌疫苗等。     

乳酸芽孢杆菌制剂对AA肉鸡生产性能的影响

本试验研究在日粮中分别添加200mg/kg乳酸芽孢菌制剂和50mg/kg土霉素,对1～49日龄AA肉鸡生产性能的影响。结果表明,乳酸芽孢菌制剂组和土霉素组的全期平均日增重比对照组提高15.29%和9.10%(P<0.05),乳酸芽孢菌制剂组比土霉素组提高5.67%(P>0.05);乳酸芽孢菌制剂组和土霉素组的全期料肉比分别比对照组降低9.09%和7.36%(P<0.05),乳酸芽孢菌制剂组比土霉素组低1.87%(P>0.05);各组成活率差异不显著。     

凝固型酸奶生产中常出现的问题与质量控制

本文介绍在凝固型酸奶生产中经常遇到的问题及产生原因,并加以研究分析、论述与解决。     

基于16S rDNA测序分析腹腔注射苦参碱的昆明小鼠肠道菌群结构

旨在通过16S rDNA测序技术分析腹腔注射苦参碱的昆明小鼠肠道菌群的结构。本研究将20只昆明小鼠随机分为2组,分别是苦参碱组(MT组)和阴性对照组(NC组),连续腹腔给药5 d,每天给药2次,收集各组粪便和各肠段组织,进行β多样性、Lefse及Metastats分析,qPCR检测差异菌种在各肠段的mRNA表达量,通过KEGG分析肠道菌群变化导致的代谢途径差异。稀释曲线结果显示,所测样本数据足以反映样品中物种多样性;β多样性分析结果显示,苦参碱可以调节肠道菌群的结构,Lefse及Metastats分析结果均显示,苦参碱显著增加了拟杆菌门(Bacteroidetes)、拟杆菌目(Bacteroidales)、Muribaculaceae、益生菌嗜酸乳杆菌(Lactobacillus acidophilus)的丰度,而显著减少了厚壁菌门(Firmicutes)、瘤胃菌科(Ruminococcaceae)和脱硫弧菌属(Desulfovibrio)的丰度。与Lefse及Metastats分析结果一致,qPCR结果显示苦参碱组小鼠粪便中嗜酸乳杆菌含量增加。同时,苦参碱可以增强嗜酸乳杆菌在各肠段的定植。通过KEGG分析发现,NC与MT组之间在聚糖的生物合成与代谢、运输与分解代谢等代谢途径存在显著差异。本研究结果表明,腹腔注射苦参碱可以显著改变昆明小鼠肠道菌群的结构,增加有益菌嗜酸乳杆菌在肠道中的定植,并造成了聚糖生物合成与代谢、运输与分解代谢等代谢途径的差异,为进一步揭示苦参碱发挥药效作用的机理奠定了基础。     

干酪乳杆菌与氟苯尼考对肉雏鸡生长性能及免疫力影响的比较研究

为比较肉雏鸡在饮水中添加干酪乳杆菌与氟苯尼考对肉雏鸡生长性能与免疫力的影响,本试验选取1日龄肉鸡120只,随机分为3个处理组,分别为对照组、干酪乳杆菌组、氟苯尼考组,每个处理组4个重复,每个重复10只,试验期为21 d,检测不同阶段各处理组的平均日增重、料重比、免疫器官指数、外周血IgG含量、盲肠sIgA含量、淋巴细胞增殖能力。结果显示,饮水中添加干酪乳杆菌对肉雏鸡体重、平均日增重、平均日采食量影响不显著,添加氟苯尼考显著抑制了肉雏鸡的生长性能(P0.05),二者对肉雏鸡料重比的影响均差异不显著。添加干酪乳杆菌对肉雏鸡免疫器官指数影响不显著,但显著提高了肉雏鸡外周血IgG含量、盲肠sIgA含量以及外周血淋巴细胞增殖能力(P0.05),添加氟苯尼考显著抑制了肉雏鸡的免疫水平(P0.05)。结果表明新进肉雏鸡在饮水中添加氟苯尼考对雏鸡的生长性能及免疫力有显著的抑制作用,应减少使用,而添加干酪乳杆菌对提高雏鸡免疫力是有益的。     

Effects of Lactobacillus amylovorus Metabolites on the Barrier Function of IPEC-J2 Cells Infected by TGEV

This study used Real-time PCR to detect the changes of expression quantity of claudin 3 (CLDN-3), cytokeratin 8 (KRT8) and mucin 1 (MUC1) three proteins mRNA in IPEC-J2 cells at three different time points.IPEC-J2 cells were infected by TGEV, we explored whether Lactobacillus amylovorus metabolites could enhance cell barrier function by maintaining or improving mRNA expression of CLDN-3, KRT8 and MUC1, whether had effects on the barrier function of IPEC-J2 infected by TGEV.The results showed that mRNA expressions of MUC1, CLDN-3 and KRT8 in the normal cell control group did not change significantly with time (P> 0.05); MRS medium culture group did not change significantly compared to the normal cell control group(P> 0.05); Gene expressions of MUC1, CLDN-3 and KRT8 proteins in Lactobacillus amylovorus metabolites alone treatment group showed significant time-dependent effect (P< 0.05).After being treated 24, 36 and 48 h, gene expressions of MUC1, CLDN-3 and KRT8 proteins in Lactobacillus amylovorus metabolites+TGEV experiment group was significantly higher than virus control group (P< 0.05).Lactobacillus amylovorus metabolites could improve MUC1, CLDN-3 and KRT8 expressions in IPEC-J2 cells, while being able to negatively regulate MUC1, CLDN-3 and KRT8 expressions that TGEV induced in IPEC-J2 cells, thereby inhencing the barrier function of IPEC-J2 cell against TGEV.     

嗜水气单胞菌ompA、flaA基因重组干酪乳杆菌对鲤生长及免疫效果分析

为构建嗜水气单胞菌ompA和flaA基因重组干酪乳杆菌并分别检测其表达产物对鲤生长及免疫效果的影响,实验将目的基因克隆至乳酸菌穿梭表达质粒pPG612中,并电转至干酪乳杆菌中,经诱导后包被饲料对鲤进行饲养56 d,称重并采集血清及组织,分析生长指标及免疫指标变化。在56 d饲养免疫结束后结果显示,生长指标显示重组干酪乳杆菌组与对照组无显著差异,表明重组干酪乳杆菌对生长无影响;免疫效果分析显示,血清中IgM表达水平显著上升。血清中AKP、LZM、SOD、CAT、C3和C4也均显著升高。荧光定量PCR检测发现,免疫后肝脏、脾脏、头肾及肠组织中的细胞免疫因子基因IL-1β、IL-8、TNF-α、 NF-κB、 TLR5及MYD88的表达水平有不同程度的显著提升;其中TLR5及MYD88表达量在Lc-mcs-flaA组高于Lc-mcs-ompA组。攻毒后Lc-mcs-ompA与Lc-mcs-flaA组免疫保护率分别为59%与54%,显著高于对照组。研究表明,本实验构建的重组干酪乳杆菌Lc-mcs-ompA与Lc-mcs-flaA免疫鲤能刺激机体产生免疫应答反应,进而提高自身存活率,为预防鱼类嗜...     

一株猪源发酵乳杆菌的体外特性研究

采用全自动曲线分析仪测定了猪源发酵乳杆菌X6的不同接种量、不同初始pH的生长曲线;采用琼脂平板扩散法检测该菌的抑菌能力,探讨该菌在不同高温下的存活时间;在体外模拟了该菌对人工胃液和人工肠液的耐受性.结果表明:在接种量1%、初始pH 5.3的条件下,该菌的生长情况最佳;该菌能够抑制大肠杆菌、金黄色葡萄球菌和沙门氏菌的生长;该菌在50、55、60℃处理2min时,存活率分别为99.19%、91.94%、80.65%;该菌在人工肠液和pH 3.0的人工胃液中存在4h后活性几乎不受影响,活菌数在109 CFU/mL以上,说明该菌具备作为益生性饲料添加剂的基本条件.     

植物乳杆菌的益生特性及其在乳制品中的应用

植物乳杆菌（Lactobacillusplanrarum）能通过胃并定植于肠道,发挥调节肠道菌群、免疫调节、降低血清胆固醇、降血压和抗氧化等益生作用。此外,由于植物乳杆菌的益生特性,国内学者申请了诸多关于植物乳杆菌菌株专利。同时,近年来有关植物乳杆菌分子多样性的研究也充分开展。另外,植物乳杆菌还被广泛应用于乳制品生产,包括功能性酸乳、发酵豆乳、干酪、功能性乳酸菌饮料等乳制品中。     

Identification and characterization of lactic acid bacteria isolated from rainbow trout, Oncorhynchus mykiss (Walbaum), with inhibitory activity against Lactococcus garvieae

A study was conducted to evaluate the probiotic properties of endogenous rainbow trout microbiota against pathogenic Lactococcus garvieae. A total of 335 bacterial strains were isolated from rainbow trout and screened for antagonistic activity against L. garvieae using an agar spot assay. Antagonistic strains were grouped by PCR amplification of repetitive bacterial DNA elements (rep‐PCR) and identified by 16S rRNA gene sequence analysis. The results revealed that the antagonistic strains belonged to the genera Lactobacillus, Lactococcus and Leuconostoc. Further probiotic characteristics, such as specific growth rate, doubling time, resistance to biological barriers, antibiotic resistance, hydrophobicity and production of antimicrobial substances, were also studied. These strains were able to survive low pH and high bile concentrations, showed good adherence characteristics and a broad spectrum of antibiotic resistance. The antagonistic efficacy was maintained after sterile filtration and was sensitive to proteinase K, indicating that proteinaceous extracellular inhibitory compounds were at least partially responsible for pathogen antagonism. Based on these results, these strains should be further studied to explore their probiotic effects in challenge experiments in vivo. This study shows clear evidence that the indigenous trout‐associated microbiota may provide a defensive barrier against L. garvieae.