猪源乳酸菌的分离、筛选、鉴定及产酸性能的研究

试验旨在分离、筛选出具有强抗逆性、产酸能力强的同源菌株。从28日龄断奶健康仔猪粪便分离得到30株乳酸菌,应用体外筛选法,筛选出在pH值2.5处理2h后的菌株13株;将此13株菌株通过浓度为0.2%胆盐后剩7株。采用牛津杯法进行抑菌试验,从7株菌中筛选出对大肠杆菌、沙门氏菌有较强抑菌作用的4株,分别为R11、R15、R18、R22,对此4株菌株进行产酸试验验证,都表现出强的产酸能力。对这4株菌进行鉴定性试验,结果R11为屎肠球菌,R15为鸡肠球菌,R18为嗜酸乳杆菌,R22为口乳杆菌。     

新疆棉花秸秆中乳酸菌的分离与鉴定

实验用MRS+CaCO3固体培养基,以新疆吐鲁番地区棉花秸秆为实验对象,分离纯化得到乳酸菌4株。经形态学、生理生化特性和16S rRNA序列同源性分析进行鉴定,结果表明:Z1、Z2菌株为植物乳杆菌(Lactobacillus plantarum),Z4、Z5菌株为戊糖片球菌(pediococcus pentosaceus)。同时测定已鉴定的4株乳酸菌的产酸速率,结果发现,Z2和Z5表现出较强的产酸速率,可进一步研发成青贮饲料添加剂。     

牛乳中乳酸菌的分离鉴定

乳酸菌与人类关系十分密切,是人肠道的正常菌群之一,对肠道内微生物群落有一定调节作用。作为益生素菌种在肠道内生长繁殖,对致病菌有一定拮抗作用,能够改善肠道环境,提高抗病力。人们对乳酸菌的分类、生理特性和作用机理等进行了较全面的探索,并已有效地应用于食品、医药工业,但在乳酸菌作为益生素饲料添加剂方面,     

分泌抗金黄色葡萄球菌细菌素乳酸菌的分离鉴定

为分离和筛选产抗金黄色葡萄球菌乳酸菌素的优势乳酸菌,利用乳酸菌分离培养基MRS从收集的各种腌制菜汁中分离培养乳酸菌,通过细菌培养特性、革兰氏染色特点、生理生化特性初步鉴定,同时根据Genbank中乳酸菌的16SrDNA序列设计特异性引物,采用PCR方法进一步鉴定,并以金黄色葡萄球菌为指示菌对乳酸菌的发酵上清液进行抑菌特性研究。结果表明,从腌渍菜汁中分离获得90株产酸菌,通过形态学、生理生化特性和PCR鉴定,结果73株产酸菌为乳酸杆菌;分泌产物抑菌试验表明,有10株菌具有抑制金黄色葡萄球菌活性,经酸排除和过氧化氢排除试验,仍然有5株乳酸菌的分泌产物具有抑制金黄色葡萄球菌活性。可见,从腌渍菜汁分离到的乳酸菌具有抑制金黄色葡萄球菌活性的特性,主要是通过分泌乳酸菌素来发挥作用。     

西藏豆科牧草青贮饲料中耐低温优良乳酸菌的筛选

本研究对西藏地区豆科牧草青贮饲料中的乳酸菌进行分离、鉴定,以期得到优良的乳酸菌菌株。以苜蓿和箭筈豌豆青贮饲料为试验材料,共分离得到6株同型发酵乳酸菌,经传统微生物培养和16S rRNA序列分析,3株(LCG9,CG35和AG11)为戊糖片球菌,2株(LCG3和LAG1)为植物乳杆菌,1株(LA3)为弯曲乳杆菌;除AG11和LAG1在5℃,LCG9和AG11在pH 3.0和8.0生长微弱外,其余乳酸菌菌株均在5~20℃,pH 3.0~8.0及3.0%和6.5% NaCl培养液中生长良好。从耐低温特性、产酸能力和发酵速率3个指标考虑,植物乳杆菌LCG3最适宜用于西藏青贮饲料生产的乳酸菌菌种。     

乳酸菌Ⅱa类细菌素抗菌机制的研究

从细胞及分子水平上就乳酸菌Ⅱa类细菌素抗菌机制及其在动物体内的抗菌作用研究作一综述。     

乳酸菌胞外多糖

本文综述了目前关于乳酸菌胞外多糖(EPS)的结构、化学组成、影响乳酸菌EPS产生的因素等方面的研究现状及乳酸菌胞外多糖的应用。     

乳酸菌富铁的研究

为了使铁离子转化为易被动物体吸收的微量元素,以防治仔猪因缺铁而造成的贫血等病症,本研究用乳酸菌富集铁元素。首先测得乳酸菌在硫酸亚铁和有机铁2种来源的铁元素中所能正常生长的最高铁离子浓度,然后加入适宜浓度的铁离子培养乳酸菌至最高活菌数。菌液离心后冲洗3次并烘干,用原子分光光度法测定乳酸菌干细胞内铁离子的含量,比较乳酸菌对2种形态铁元素的富集能力。最后做饲养试验。结果表明:乳酸菌对有机铁的耐受质量浓度(0.5 g/L)比硫酸亚铁(0.1 g/L)高;乳酸菌对有机铁的富集能力(1.590 mg/g)比硫酸亚铁(0.024mg/g)强。含有机铁的乳酸菌制剂对降低断奶仔猪死亡率有显著效果。     

乳酸菌的耐酸性机制

<正>乳酸菌是一类能利用可发酵糖产生大量乳酸的细菌的通称。乳酸菌在自然界分布广泛,可栖居于人和动物的肠道以及其它器官内。很久以前人们就利用乳酸菌来发酵动物制品(乳、肉、鱼等)和植物制品(蔬菜、葡萄酒、橄榄等)。随着食品发酵工业的不断发展壮大,开发利用乳酸菌的经济效益也不断在增长。虽然乳酸菌在发酵食品中的含量非常少,但是对食品的感官品质和质量却有决定性作用,因此,发酵剂菌株的质量功能特性和生长特性对于产品的成功发酵是非常必要的。乳酸菌不但包括在食品发酵中使用的一     

乳酸菌在家禽生产中的应用

乳酸菌是人、畜禽胃肠道以及一些食物中的重要菌群之一,广泛用于食品、饲料和医药等领域,是一类具备多种益生功能的微生物.以乳酸菌为代表的微生态制剂,具有改善机体生长性能、促进机体免疫系统发育防止发生疾病、维持机体胃肠道微生态平衡、提升抗氧化能力、促进机体对营养物质的消化吸收等作用,一直是各大饲料企业以及家禽养殖业关注的焦点...     

呼伦贝尔草原野生牧草青贮中优良乳酸菌的分离及鉴定

本研究对呼伦贝尔草原牧草青贮饲料中的乳酸菌进行了分离、鉴定,旨为筛选出优良乳酸菌菌株。以4个地区不同群落牧草的青贮饲料为试验材料,并采用传统微生物学鉴定方法及16S rRNA序列分析对分离得到的乳酸菌菌株进行了鉴定。菌株DME53为草乳杆菌,DMG108为干酪乳杆菌,DMC80为植物乳杆菌,DMG138为短乳杆菌,DMG139为戊糖片球菌;其中菌株DMG138为异型发酵乳酸菌,其余4株菌均为同型发酵乳酸菌。除DMG139在40和45 ℃下生长微弱外,其余菌株均在5~45 ℃不同温度条件下, 3.0%和6.5% NaCl培养液中良好生长。除菌株DME53在pH 3.0下不能生长外,其余菌株均在pH 3.0~8.0条件下良好生长或微弱生长。菌株DMC80具有产酸能力较强、发酵速率较快、耐酸、耐低温等特性,可作为制备适用于呼伦贝尔地区青贮饲料菌制剂的优良菌株。     

乳酸菌青贮技术研究进展

本文综述了国内外乳酸菌青贮技术的内容、应用及效果, 总结了添加乳酸菌对青贮饲料发酵品质和有氧稳定性的影响, 以及不同乳酸菌菌株的筛选和鉴定及其对动物生产性能的影响。通过分析以上内容, 对乳酸菌青贮技术今后的发展方向, 特别是分子生物学在乳酸菌青贮技术研究中应用的广阔前景做了展望。     

牦牛肠道与粪便乳酸菌的分离鉴定及PCR-16SrDNA鉴定

以取自四川省不同地区的牦牛粪便、肠道内空物为材料，用MRS琼脂双层培养基进行厌氧培养，分离到50株乳酸菌，经生化鉴定为嗜热链球菌（2株）、乳酸乳球菌（1株）、保加利亚乳杆菌（5株）、嗜粪乳杆菌（10株）、嗜酸乳杆菌（8株）、乳酸乳杆菌（9株）、肠乳杆菌（10株）、弯曲乳杆菌（5株）。采用乳酸菌16 SrDNA通用引物，对分离的8种菌的16S rDNA-段可变区序列进行扩增，均得到大小约470bp的产物；扩增产物经纯化、测序后与GenBank中标准菌株的核甘酸序列比较，同源性均大于97．5％，同源性分析与生化试验的结果是一致的。证实，牦牛肠道和粪便的乳酸菌较为丰富，且乳杆菌的数量较多，这可能与牦牛复杂的生长环境有关。     

耐低温乳酸菌的分离与优化培养

从青贮玉米(Zea mays)以及新鲜泡菜中分离乳酸菌,通过初筛和复筛获得1株产酸能力较强的耐低温乳酸菌L2;对其进行了形态学描述和生理生化鉴定,对照伯杰式手册确定其种属;采用Box-Behnken实验设计进行培养条件优化实验,确定了该菌的最佳发酵条件。结果表明,该菌的最佳发酵条件为接种量3.1%、初始pH6.4、培养温度18.4 ℃。     

Oxalate-degrading capacities of lactic acid bacteria in canine feces

In this study, lactic acid bacteria in canine feces were isolated and identified, and their oxalate-degrading capacities were evaluated. The oxalate-degrading capacities were determined for 24 of 47 (51.06%) lactic acid bacteria isolates. Of these, 8 isolates [Leuconostoc mesenteroides (RL75), Lactococcus garvieae (CD2), Lactococcus subsp. lactis (CS21), Enterococcus faecium (CL71 and CL72), and Enterococcus faecalis (CD14, CS62, and CD12)] degraded more than 5% of the oxalate present, while the others degraded less than 5% of the oxalate in vitro. Isolates that degraded more than 5% of the oxalate present were selected for further examination. The oxalate-degrading capacities of individual isolates, a mixture of Enterococcus, a mixture of Lactococcus, and a mixture of the eight isolates were evaluated in media containing different concentrations of glucose (sufficient, insufficient, or no glucose). In comparison with the control medium, all of the individual isolates and mixtures of isolates could degrade oxalate in all three groups (P<0.05). In most cases, the isolates growing in medium with 20 g/L of glucose had higher oxalate-degrading capacities than those growing in medium with 2.5 g/L of glucose or no glucose. The mixture of all isolates showed higher oxalate-degrading capacity than the individual isolates and other mixtures. The oxalate-degrading capacities of the isolates were isolate dependent.     

乳酸菌青贮添加剂的研究与应用

很多添加剂被用来促进青贮发酵过程,其中研究最广泛的就是乳酸菌青贮添加剂。本文主要阐述了在青贮中加入乳酸菌添加剂可以促进作物的发酵速度,并且改善家畜的生产性能。     

优质乳酸菌的应用

人们的认识乳酸菌之前就已利用它们来加工和保存食品。目前，乳酸菌已广泛应用于发酵酸乳、干酪、发酵豆乳、酿造食品、腌渍物、面包、发酵肉制品及食品防腐保藏等方面，乳酸菌不仅可以提高食品保藏性和附加值，而且有其特殖生理活性和保健功能。     

Health effects of lactic acid bacteria ingested in fermented milk

Health effects of lactic acid bacteria ingested in fermented milk. Many recent studies have shown the health effects of various strains of lactic acid bacteria in humans and animals and have tried to describe their action mechanism in the digestive tract. A number and a variety of potential beneficial effects have been published. Some of these effects have already been described such as the improvement of lactose digestion and the treatment of diarrheal disorders. Other health effects are still a subject of controversy such as the decrease of serum cholesterol and the reduction of tumor formation. The aim of this article is to summarize the probiotic effects of lactic acid bacteria, their mechanisms, and the fate of these microorganisms during their transit in the digestive tract.     

Oxalate degradation by intestinal lactic acid bacteria in dogs and cats

This study evaluated the ability of the lactic acid bacteria (LAB) component of canine and feline feces to degrade oxalate in vitro. Oxalate degradation by individual canine-origin LAB was also evaluated. The effects of various prebiotics on in vitro oxalate degradation by selected oxalate-degrading canine LAB was also evaluated. Canine fecal samples reduced oxalate levels by 78 +/- 12.2% (mean +/- S.D.; range: 44-97%, median: 81%). Feline results were similar, with oxalate reduction of 69.7 +/- 16.7% (mean +/- S.D.; range: 40-96%, median: 73%). Thirty-seven lactic acid bacteria were isolated from canine fecal samples. Mean oxalate degradation was 17.7 +/- 16.6% (mean +/- S.D.; range: 0-65%, median: 13%). No oxalate degradation was detected for four (11%) isolates, and 10/37 (27%) degraded less than 10% of oxalate. The effects of lactitol, arabinogalactan, guar gum, gum Arabic, inulin, maltodextrin or a commercial fructooligosaccharide (FOS) product on in vitro oxalate degradation by five canine LAB isolates were highly variable, even within the same bacterial species. Overall, in vitro degradation was significantly greater with guar gum compared to arabinogalactan (P < 0.05), gum Arabic (P < 0.05), and lactitol (P < 0.01). This study suggests that manipulation of the LAB component of the canine and feline gastrointestinal microflora may decrease intestinal oxalate, and correspondingly intestinal oxalate absorption and renal excretion, thus potentially reducing oxalate urolithiasis.