猪源乳酸菌抑制致病性大肠埃希菌研究

为筛选能够抑制猪源致病性大肠埃希菌的优势乳酸菌,采集不同日龄的健康仔猪新鲜粪便,分离纯化得到35株疑似乳酸菌。应用牛津杯法对3株致病大肠埃希菌抑制作用进行研究,筛选出2株有抑菌作用的疑似乳酸菌(11号和14号)。利用生化鉴定和16SrDNA序列同源性分析,该两株菌被鉴定为乳杆菌属唾液乳杆菌;综合牛津杯法和生长曲线、pH的测定结果,筛选出产酸性能和抑菌效果好的14号菌株,为研制仔猪用微生态制剂奠定了基础。     

一株仔猪源枯草芽孢杆菌的分离鉴定及其益生特性研究

为了筛选优质猪源益生菌菌种资源,为畜禽微生态制剂的研究与开发提供优质候选菌株,试验以健康仔猪新鲜粪便为分离材料,通过高温处理分离芽孢杆菌,并对其进行形态特征、生化及分子生物学鉴定与益生特性研究。结果表明:从健康仔猪新鲜粪便中分离获得多株细菌,选取其中1株生长快速、形态特征典型的菌株进行鉴定,确定该分离菌为枯草芽孢杆菌。益生特性研究表明,该分离菌菌株具有较强的耐热、耐酸、耐胆盐等益生特性,同时具有一定的拮抗致病菌作用,对大部分抗生素敏感,对小鼠无毒副作用,可作为畜禽微生态制剂菌种的候选菌株。     

益生凝结芽孢杆菌的筛选及生物学特性研究

本实验依据益生菌筛选的常规方法和凝结芽孢杆菌的判定标准,旨在从健康仔猪粪便中分离获得益生性能优良且安全的益生凝结芽孢杆菌,并通过体外模拟动物肠道环境,评价其益生特性和应用特点。本研究从70余株猪源芽孢杆菌中筛选鉴定出4株凝结芽孢杆菌,分别命名为BC147、BC235、BC303和BC310。结果表明:4株菌对大肠杆菌K88,鸡肠炎沙门菌,猪肠炎沙门菌,金黄色葡萄球菌,鼠伤寒沙门菌均表现出良好的抑菌作用。益生及耐受性研究发现,四株菌均具有良好黏附能力,并对胆盐和低酸环境表现出较强的耐受能力,其中BC303对仔猪肠黏液的黏附率高达41.67%,在p H 4的条件下其营养细胞存活率高达91.0%,在0.3%胆盐中暴露2 h,其存活率仍然维持在40%以上。同时,四株菌均具有一定的蛋白酶、淀粉酶和纤维素酶产生能力。结果显示,从健康仔猪肠道及粪便分离筛选获得的凝结芽孢杆菌具有良好的益生性和安全性,其在畜禽养殖中具有广泛应用前景。     

复合发酵菌株对乳中碳源利用能力的分析及菌株间互作关系预测

发酵乳制品具有风味、营养、功能等特性上的优势,在乳制品消费中比例逐年上升。本研究以菌株间碳源间的互作为中心,分析了传统酸奶发酵剂菌株利用碳源的能力及在不同碳源中的生长特性,对菌株间的相互作用进行分析预测。研究发现:所有菌株均能利用葡萄糖,嗜热链球菌C4和C1-2能利用乳糖,干酪乳杆菌CM1和嗜热链球菌C4能利用半乳糖;通过分析菌株在不同碳源中的生长速率及迟滞期,发现嗜热链球菌C4在乳糖中的迟滞期最短(1.30±0.02),其降解乳糖产生的葡萄糖和半乳糖供干酪乳杆菌CM1生长(2.84±0.16),随后嗜热链球菌C1-2利用乳糖生长(2.89±0.22)。在此发酵剂菌株中C4菌株为发酵产酸的关键菌株,其快速产酸能力促进产品的凝乳,其降解乳糖产生葡萄糖和半乳糖供其他菌株生长;干酪乳杆菌CM1快速利用半乳糖和葡萄糖的能力可进一步促进产品的凝乳;产酸较慢的嗜热链球菌C1-2是一株产黏的菌,能促进酸奶组织状态和良好质地的形成。本研究对菌株利用碳源能力的分析为复合发酵剂的开发提供了有效数据。     

三株乳酸杆菌的分离鉴定与益生特性研究

本研究通过分离鉴定猪肠道内乳酸杆菌并对其益生特性进行比较分析,旨在为乳酸杆菌在仔猪饲粮中的应用提供科学依据。试验选取健康猪粪便,利用选择性培养基进行厌氧培养和单克隆纯化,共获得三株乳酸杆菌,通过生化鉴定、16Sr RNA基因序列测定和同源性分析,确定分离菌株分别为植物乳杆菌、唾液乳杆菌、嗜酸乳杆菌;采用牛津杯法、活菌计数法和细胞试验等研究三株乳酸杆菌体外抑菌活性、黏附性及竞争性黏附猪小肠上皮细胞(IPEC-J2)的益生特性。结果表明:与对照组相比,三株乳酸杆菌培养上清液的抑菌圈直径(P0.01)和抑菌效果(P0.01)差异均极显著,并且以植物乳杆菌培养上清液的抗菌效果为最佳;三株乳酸杆菌均可黏附于IPEC-J2细胞,并且以植物乳杆菌黏附IPEC-J2的菌数为最多;与对照组相比,三株乳酸杆菌对大肠杆菌黏附IPEC-J2细胞均具有抑制作用(P0.01),并且以植物乳杆菌抑制黏附的效果最好。     

猪源乳酸菌制剂的制作及其在仔猪生产上的应用

试验旨在研究优良乳酸菌(来源于健康仔猪粪便)制剂的制作与其饲喂效果,探讨其对哺乳仔猪(7～28日龄)与断奶仔猪(29～60日龄)生长性能的影响。将R11(屎肠球菌)、R15(鸡肠球菌)、R18(嗜酸乳杆菌)、R22(口乳杆菌)、R保(保加利亚杆菌)各株优良菌株混合培养进行竞争性筛选,并对其种子液培养基成分进行设计与选择,筛选出最佳混合菌种与合适的种子液。分别按0.2%、0.3%比例添加到哺乳与断奶仔猪基础日粮中,并与抗生素组作对照进行饲喂试验。试验结果表明,屎肠球菌、鸡肠球菌、嗜酸乳杆菌、口乳杆菌混合培养后较单独培养pH显著降低(P<0.05);并且配方二培养基二的菌数显著高于配方一、三、四。两组仔猪哺乳期、断奶期的平均日采食量、平均日增重、每头总采食量、饲料转化率、腹泻率与死亡率差异均不显著(P>0.05),且益生菌组较抗生素组断奶后(29～60日龄)仔猪平均日增重提高9.21 g,饲料转化率降低0.11。结果表明,猪源乳酸菌制剂可以替代抗生素应用于仔猪。     

一株强抗逆性猪源乳酸菌的筛选及生物学特性研究

本试验从健康仔猪粪便样品中分离纯化得到5株乳酸菌,并应用16S rRNA基因进化分析对其进行种属鉴定。通过对此5株菌进行耐热、耐酸、耐胆盐、耐贮藏性能和抗生素抗性选育,与伤寒沙门氏菌、大肠杆菌以及金黄色葡萄球菌进行混合培养,探究其对大肠杆菌、鸡白痢沙门等病原菌的抑菌效果,最终筛选出一株具有强抗逆性和优良益生特性的屎肠球菌,并进一步对其生长性能和生理生化特性进行了系统研究,为菌株的开发与应用提供理论参考。 [关键词] 仔猪粪便|屎肠球菌|筛选|抗逆性|益生特性     

一株高产酸乳酸菌的分离、鉴定及高密度发酵研究

为获取产酸能力强、发酵性能好、具有强抑菌能力的乳酸菌,本试验以35日龄断奶健康仔猪粪便为菌源,对其乳酸菌进行筛选、分离、鉴定,并对分离菌株进行发酵性能研究。从35日龄断奶健康仔猪粪便中分离得到6株目标菌株,经产酸测试及抑菌试验后,得到一株产酸能力强、抑菌效果良好的筛选菌株,命名为RSJ-5。通过对RSJ-5菌株的菌落与菌体形态观察、生理生化鉴定试验、糖醇发酵试验,确定其为嗜酸乳杆菌。利用50 L发酵罐接种RSJ-5菌株厌氧发酵36 h,发酵液活菌数达158 CFU/mL,乳酸钙含量为85 mg/mL,pH4.2,发酵液对大肠杆菌、沙门氏菌有较强抑菌作用。结果表明RSJ-5嗜酸乳杆菌具备优良乳酸菌发酵剂的性能,探索了发酵工艺的可行性,为液体饲料(乳酸菌发酵液)大规模发酵生产提供参考。     

芽孢杆菌B13的分离鉴定及其抑菌作用研究

试验旨在发掘有效的抗性菌以替代部分抗生素,并研究其抑菌作用,以大肠杆菌K88、鼠伤寒沙门氏菌和金黄色葡萄球菌为指示菌,采用凝胶打孔法从猪肠道内容物中筛选出一株对3种病原菌均具有抑菌活性的菌株,利用形态特征观察、革兰氏染色、16SrDNA序列同源性比对鉴定菌株,并对其抑菌条件和生长条件进行优化。结果显示,试验筛选到1株对大肠杆菌K88、鼠伤寒沙门氏菌和金黄色葡萄球菌均具有较强抑制作用的菌株,经鉴定确定其为芽孢杆菌(Bacillus sp.),并命名为芽孢杆菌B13。此分离菌为革兰氏阳性菌,单生或成对生长。生长试验结果表明,该分离菌在pH为6.0,温度为34℃,以蔗糖为碳源、蛋白胨为氮源时,生长速度最快;在pH为7.0,温度为35℃,以麦芽糖为碳源、蛋白胨为氮源时,抗鼠伤寒沙门氏菌、黄色葡萄球菌和大肠杆菌K88活性最高。本试验通过对芽孢杆菌B13的特性进行研究发现,此菌株具有较好的抑菌效果,在抑菌方面具有良好的开发应用前景。     

抑霉乳酸菌的筛分及其抑菌特性研究

试验旨在获取生物抑霉的优良菌株以及为质量安全青贮饲料生产提供高效菌剂。从青贮饲料、酸奶以及奶豆腐中分离纯化出乳酸菌和霉菌,并且通过双层平板法对具有抑制霉菌活性的乳酸菌菌株进行筛选,测定其上清液抑霉效果;采用蛋白酶处理和高温处理法分析乳酸菌抑霉的有效成分。结果表明:分离筛选的乳酸菌和霉菌经鉴定为植物乳杆菌和黄曲霉菌,且植物乳杆菌对黄曲霉菌的生长有明显抑制作用。蛋白酶处理对乳酸菌无细胞上清液的抑菌活性有不同影响,而加热处理并不改变其抑菌效果。研究表明,植物乳杆菌对黄曲霉菌生长有明显的抑制作用,推测其抑菌活性物质为蛋白质、肽类等,并且这些抑菌活性物质的热稳定性较高。     

仔猪益生乳酸菌的分离及其抗逆性筛选

从仔猪肠道中分离出45株乳酸菌,从中筛选出4株耐酸、耐胆盐并具有良好益生性的菌株,小鼠试验证明其具有可靠的安全性,所分离出的4株乳酸杆菌可用于仔猪生产中用。     

Effects of dietary fructooligosaccharide on selected bacterial populations in feces of dogs

OBJECTIVE: To evaluate fecal concentrations of selected genera of colonic bacteria in healthy dogs, and to investigate effects of dietary fructooligosaccharides (FOS) on those bacterial populations. ANIMALS: 6 healthy adult Beagles. PROCEDURE: Dogs were randomly assigned to 2 groups of 3 and fed an unsupplemented diet for 370 days. After 88 days, fecal samples were collected. Another fecal sample was collected from each dog 282 days later. Group A then received a diet supplemented with FOS, and group B continued to receive the unsupplemented diet. Twenty-eight to 29 days later, fecal samples were collected. Diets were switched between groups, and fecal samples were collected 31 and 87 days later. Concentrations of Bifidobacterium spp, Lactobacillus spp, Clostridium spp, Bacteroides spp, and Escherichia coli in freshly collected feces were determined. Effects of diet and time on bacterial concentrations were compared between groups. RESULTS: Bifidobacterium spp and Lactobacillus spp were inconsistently isolated from feces of dogs fed either diet. Sequence of diet significantly affected number of Bacteroides spp subsequently isolated from feces, but diet had no effect on numbers of Clostridium spp or E coli. CONCLUSIONS AND CLINICAL RELEVANCE: Some genera of bacteria (eg, Bifidobacterium) believed to be common components of colonic microflora may be only sporadically isolated from feces of healthy dogs. This deviation from expected fecal flora may have implications for the effectiveness of supplementing diets with prebiotics.     

猪源乳酸杆菌对仔猪肠道微生物的影响

从猪的新鲜粪便中培养分离获得的三株乳酸杆菌对常见的病原性菌大肠杆菌、猪霍乱沙门氏菌和金黄色葡萄球菌具有一定的抑菌作用。动物接种试验证明,试验分离获得的猪源乳酸杆菌饲喂动物安全,符合益生菌的条件,可以作为益生菌添加到饲料中。在试验中发现,猪源乳酸杆菌和EM菌都有促进仔猪生长发育、提高生产性能、降低发病率和死亡率的作用。在调整仔猪肠道菌群方面:试验各组效果较对照组差异均显著<0.05)。试验二组的效果最好:在增加乳酸杆菌方面,比试验一组高18.5%,比试验四组高12.5%;在减少大肠杆菌方面,比试验二组高6.25%,比试验四组高6.25%;在增加肠道细菌总数方面,比试验一组高37.5%,比试验四组高37.5%。所以,本试验从猪体内获得的乳酸杆菌安全性良好,对改善仔猪肠道环境具有一定的作用。     

肉牛粪污中纤维素降解菌的分离筛选

为了获得有效降解肉牛粪污中纤维素的细菌,采用以羧甲基纤维素钠为碳源的方法对牛粪及其自然堆肥样品进行纤维素降解菌的分离,对已分离菌株进行形态学和分子生物学鉴定,再结合纤维素刚果红水解圈测定和滤纸条降解试验做进一步研究。结果表明,以羧甲基纤维素钠为碳源,初步分离得到牛粪样品及堆肥中32株纤维素降解菌,进一步筛选得到有刚果红水解圈菌株4株,分别为XQ-1、XQ-2、XQ-3、XQ-4,其对滤纸条具有一定的降解能力,经16S rDNA鉴定,4株菌株分别为大肠埃希菌（Escherichia coli）、黏质沙雷菌（Serratia marcescens）、雷氏普罗威登斯菌（Providencia rettgeri）和费格森埃希菌（Escherichia fergusonii）。     

不同来源乳酸菌的分离与鉴定

Six strains of Lactobacillus were isolated from traditional indigenous dairy products, piglet’s feces and chicken intestine, designated as LS, LT, LJ1, LJ2, LZ1 and LZ2， respectively. Identifications were done according to bacteria morphology, physiological and biochemical properties,16S rDNA sequence homology analysis, and their characteristics were researched. The results showed that LS, LT, LJ1 and LZ2 strains were Lactobacillus brevis, LJ2 strain was Enterococcus faecium, LZ1 strain was Lactobacillus acidophilus. All of the six strains had obvious bacteriostasis effect on Listeria monocytogenes, Salmonella typhimurium, Escherichia coli and Staphylococcus aureus.     

散养成年蛋鸡空肠乳酸菌群的区系分析

试验以5只55周龄散养健康成年蛋鸡空肠内容物为样本,用无菌生理盐水稀释至10-6稀释浓度,吸取0.1 mL菌液滴于MRS平板上,置37℃培养箱培养24 h,分离乳酸菌。将分离纯化得到的乳酸菌,通过革兰氏染色、菌落形态观察、糖发酵试验进行乳酸菌种属鉴定。结果显示,从55周龄散养健康成年蛋鸡空肠中分离筛选出20株乳酸菌,经革兰氏染色后镜检显示,分离菌株有杆状和球形2种;经糖发酵试验鉴定为7个乳酸菌种,分别为唾液乳杆菌唾液亚种、棒状乳杆菌扭曲亚种、唾液乳杆菌水杨素亚种、能动乳杆菌、格氏乳杆菌、嗜酸乳杆菌和德氏乳杆菌保加利亚亚种。     

Occurrence of fimbriae and enterotoxins in Escherichia coli strains isolated from piglets in Poland.

1125 and 1146 E. coli strains isolated from suckling and weaned piglets with diarrhea, respectively, and 724 strains from healthy piglets were tested for the presence of fibriae and production of enterotoxins. The fimbriae were determined by hemagglutination and slide agglutination tests, enterotoxins—by the use of ileal loop test in piglets (LT and STb enterotoxins) and suckling mouse assay (STa enterotoxin). It was found that 72.8 and 53.0% strains, isolated from diseased suckling and weaned piglets, respectively, possessed specific fimbrial hemagglutinins, in most cases with K88 antigen. Additionally, 987P fimbriae were detected in 14.0 and 0.7% strains isolated from piglets with diarrhea. Only 5 strains (0.7%) recovered from healthy piglets had specific fimbriae, usually with undetermined antigenic structure. F1 fimbriae (called common or unspecific) were found in strains isolated both from diseased (15.2 and 16.3% strains, respectively) and healthy piglets (27.1% strains). It was noted that the strains isolated from suckling and weaned piglets with diarrhea in most cases were enterotoxigenic (90.5 and 69.1% strains, respectively) and most frequently produced heat-labile toxin LT alone or with STb. 18.5% of enterotoxigenic strains isolated from healthy piglets produced STa toxin.     

A survey of aerobic bacteria and fungi in the feces of healthy psittacine birds

Fecal samples from 61 clinically healthy psittacine birds of a wide variety of species were cultured for bacteria and fungi. The most common bacterial isolates were gram-positive bacilli, which were recovered from 60 of the 61 birds. These organisms included Lactobacillus, Bacillus, Corynebacterium, and Streptomyces. Gram-positive cocci, cultured from the feces of 21 of the birds, included Staphylococcus epidermidis, Streptococcus spp., Aerococcus spp., and Micrococcus spp. Only 6 of the 61 psittaciformes yielded gram-negative bacteria, with Escherichia coli being the most frequent isolate. Gram-negative bacilli were recovered from 4 of the 31 privately owned birds and 2 of the 30 petshop birds sampled. In addition to the bacteria, Candida albicans, Cryptococcus laurentii, and Aspergillus sp. were isolated from 13 fecal cultures. Candida albicans was isolated exclusively from 5 petshop birds. The number of birds yielding Corynebacterium and gram-negative bacteria increased with age, whereas the number of birds yielding lactobacilli and yeasts decreased with age. The organisms isolated and their significance as potential pathogens in psittacine birds are discussed.     

Characterization of Campylobacter lanienae from pig feces

To isolate Campylobacter spp., the feces of healthy cattle, pigs, and broilers were examined between June 1999 and January 2000. Campylobacter lanienae strains were isolated from the feces of healthy pigs, but not from the feces of cattle or broilers. In six C. lanienae isolates, there was only 21-38% DNA-DNA homology to Campylobacter hyointestinalis subsp. lawsonii strain NCTC 12901. Thus, the primary host of C. lanienae is likely to be the pig and C. lanienae appears to be a species distinct from C. hyointestinalis subsp. lawsonii. In addition, an intervening sequence of 226 bp in the 16S rRNA gene was found in four isolates.