促进猪生长的新探讨(二)

前生命期物(Probiotics) 前生命期物现巳广泛用以替代日粮中所使用的抗菌素物质。前生命期物在动物消化道内对微生物有着与抗菌素相反的作用。抗菌素在动物消化道内通过抑制和破坏细菌来控制微生物群体,用前生命期物实际是引入活的细菌于肠道内。

Probiotics and prebiotics in chronic inflammatory bowel diseases

The prokaryotic and eukaryotic cells of the colon exist in a highly complex, but harmonious relationship. Disturbances in this remarkable symbiosis can result in the development of inflammatory bowel diseases (IBD). Although the etiology of IBD is not entirely understood, it is known that the chronic inflammation of Crohn’s disease, ulcerative colitis and chronic pouchitis are a result of an overly aggressive immune response to the commensal intestinal flora in genetically susceptible hosts. Recent studies have enhanced our ability to understand the interaction between the host and its intestinal microflora and the role the microflora plays in maintaining intestinal homeostasis. As we begin to understand the benefi ts conferred to the intestine by the microflora, the notion of modifying the composition of the bacterial load to improve human health has arisen. A signifi cant body of research now exists investigating the role of probiotics and prebiotics in ameliorating chronic intestinal inflammation. This article will begin with an overview of the role of the commensal microflora in maintaining mucosal immune homeostasis, and how a dysregulated immune response to the intestinal microflora results in IBD. This will be followed by a summary of the use of probiotics and prebiotics in experimental and human IBD.

Effect of a fermented milk containing Bifidobacterium lactis DN-173010 on Chinese constipated women

AIM: To investigate the effect of a fermented milk containing Bifidobacterium lactis DN-173010 and yogurt strains (BIO) on adult women with constipation in Beijing.METHODS: A total of 135 adult females with constipation were randomly allocated to consume for 2 wk either 100 g of the test fermented milk or 100 g of an acidified milk containing non-living bacteria (control).Stool frequency,defecation condition scores,stool consistency and food intake were recorded at baseline and after 1 and 2 wk in an intention-to-treat population of 126 subjects.In parallel,safety evaluation parameters were performed.RESULTS: At baseline,no differences were found between groups.Following consumption of test product,stool frequency was significantly increased after 1 wk (3.5 ± 1.5 vs 2.4 ± 0.6,P < 0.01) and 2 wk (4.1 ± 1.7 vs 2.4 ± 0.6,P < 0.01),vs baseline.Similarly,after 1 and 2 wk,of test product consumption,defecation condition (1.1 ± 0.9 vs 1.9 ± 1.2,P < 0.01 and 0.8 ± 1.0 vs 1.9 ± 1.2,P < 0.01,respectively) and stool consistency (1.0 ± 0.8 vs 1.5 ± 1.1,P < 0.01 and 0.6 ± 0.8 vs 1.5 ± 1.1,P < 0.01,respectively) were significantly improved.Compared with the control group,stool frequency was also significantly increased (3.5 ± 1.5 vs 2.5 ± 0.9,P < 0.01 and 4.1 ± 1.7 vs 2.6 ± 1.0,P < 0.01,respectively),and defecation condition (1.1 ± 0.9 vs 1.6 ± 1.1,P < 0.01 and 0.8 ± 1.0 vs 1.6 ± 1.1,P < 0.01,respectively) and stool consistency (1.0 ± 0.8 vs 1.4 ± 1.0,P < 0.05 and 0.6 ± 0.8 vs 1.3 ± 1.0,P < 0.01,respectively) significantly decreased after 1 and 2 wk of product consumption.During the same period,food intake did not change between the two groups,and safety parameters of the subjects were within normal ranges.CONCLUSION: This study suggests a beneficial effect of a fermented milk containing B.lactis DN-173010 on stool frequency,defecation condition and stool consistency in adult women with constipation constipated women after 1 and 2 wk of consumption.

Role of a probiotic (Saccharomyces boulardii) in management and prevention of diarrhoea

AIM： To assess the efficacy and safety of Saccharomyces boulardii （S. boulardii） in acute watery diarrhoea and its role in reducing the frequency of episodes of diarrhoea in subsequent two months. METHODS： Children from 2 mo to 12 years of age, with acute diarrhoea were selected according to inclusion criteria and randomised in S. boulardii group （treated with ORS, nutritional support and S. boulardii, 250 mg bid） and in control group （treated with ORS and nutritional support only）. Active treatment phase was 5 d and each child was followed for two months afterwards. Frequency and consistency of stools as well as safety of drug was assessed on every visit. A comparison of two groups was done in terms of number of diarrhoeal episode in subsequent two months. RESULTS： There were fifty patients in each group. Baseline characteristics such as mean age and the average frequency of stools were comparable in S. boulardii and control group at the time of inclusion in the trial. By d 3 it reduced to 2.7 and 4.2 stools per d respectively and by d 6 it reduced to 1.6 （5. boulardii Group） and 3.3 （control group）. The duration of diarrhoea was 3.6 d in S. boulardii group whereas it was 4.8 d in control group （P = 0.001）. In the following two months, S. boulardii group had a significantly lower frequency of 0.54 episodes as compared to 1.08 episodes in control group. The drug was well accepted and tolerated. There were no reports of the side effects during treatment period CONCLUSION： S. boulardii significantly reduces the frequency and duration of acute diarrhoea. The consistency of stool also improves. The drug is well-tolerated.

Influences of enteral nutrition combined with probiotics on gut microflora and barrier function of rats with abdominal infection

AIM： To investigate the influences of enteral, parenteral nutrition and probiotics delivered by gut on intestinal microecology, epithelial tight junctions, immune and barrier function of rats with abdominal infection. METHODS： Rat abdominal infection models established with cecal ligation and perforation method, were divided into three groups： parenteral nutrition （PN group, n = 7）, PN＋enteral nutrition （EN group, n = 7） and PN ＋ EN ＋ probiotics （probiotics group, n = 7） via the needle jejunostomy and neck vein for five days. The total nutritional supplement of the three groups was isonitrogenic and isocaloric. Probiotics was delivered by jejunostomy 10 mL/d （1 x 10^8 cfu/mL）. The rats were killed on the sixth day. The feces in the cecum were cultured for anaerobic bacterial growth and analyzed with bacterial group DNA fingerprint profile with random amplified polymorphic DNA. The transmembrane binding proteins （occludin） and IgA level in plasma cells of intestine epithelium in colon and terminal ileum were measured by an immunohistochemistry method. The ultrastructure of intestinal epithelial tight junctions in colon and small intestine was observed by electronmicroscopy. Vena cava blood and the homogenated tissue of liver, lung and mesenteric lymph nodes were cultured to determine the bacterial translocations, and endotoxin in the blood from portal vein was detected. RESULTS： （1） The amount of bacteria of gut species in EN group and probiotic group was higher than that in PN group. The DNA-proflles in EN group and probiotic group were similar to that of normal rats. The number of DNAprofiles in probiotics group was much more than that in PN group and EN group. Moreover, there were strange stripes in PN group. （2） The expression of occludin and IgA in the small and large intestine in EN group （2.309 ± 0.336, 15.440 ± 2.383） and probiotic group （2.938 ± 0.515, 16.230 ± 3.183） was improved as compared with PN group （1.207 ± 0.587, P 〈 0.05, 11.189 ± 2.108, P 〈 0.01）. The expression of occludin in probiotic group （intestine： 2.93 ± 0.515; cecum： 3.40 ± 0.617） was higher than that in EN group （intestine： 2.309 ± 0.336; cecum： 2.076 ± 0.670; P 〈 0.05）. The expression of IgA, especially in EN group （intestine： 15.440 ± 2.383） and probiotic EN group （large intestine： 12.516 ± 1.542） significantly increased as compared with PN group （intestine： 11.189 ± 2.108; cecum： 10.160 ± 1.643; P 〈 0.01）. The intestinal epithelial tight junctions and microvilli of the probiotic group were more intact than those in the PN group. （3） The bacterial translocations in blood, liver, lung and mesenteric lymph nodes, and the levels of endotoxin were significantly reduced in probiotic （0.082 ± 0.029） and EN （0.125 ± 0.040） groups as compared with PN group （0.403 ± 0.181, P 〈 0.05）. CONCLUSION： Application of EN combined with probiotics could improve the expression of transmembrane binding proteins （occludin） and IgA, correct the intestinal flora disturbance, maintain gut barrier functions and tight junctions, and reduce the occurrence of gut bacterial translocation.

Role of probiotics,prebiotics and synbiotics in chemoprevention for colorectal cancer

Colorectal cancer is the third most common form of cancer.Current treatments are all associated with a high risk of complications and a low success rate.Recently,synbiotics have been proposed as a new preventive and therapeutic option.There is no direct experimental evidence for cancer suppression in humans as a result of the consumption of pro-,pre-or synbiotics.However,there is a wealth of evidence emerging from laboratory studies.The mechanisms by which pro-,pre-and synbiotics may inhibit colon cancer are now beginning to be understood and will be addressed in the present review.

A probiotic treatment containing Lactobacillus,Bifidobacterium and Enterococcus improves IBS symptoms in an open label trial

Objective： To evaluate the efficacy and safety of live combined Bifidobacterium, Lactobacillus and Enterococcus capsules in treatment of irritable bowel syndrome, Methods： Eighty-fve patients [male 32, female 53; age （45.31±11,72） years] were given live combined Bifidobacterium, Lactobacillus and Enterococcus capsules 1260 mg/d t.i.d. ×4 weeks. Syndrome scales were used to evaluate the efficacy in gastrointestinal syndrome. Fecal flora was also measured before and after the treatment. Six bacteria were cultured and the colony forming units were counted in stool. SPSS was used for data analysis. Results： Seventy-four patients finished the follow-up. No side-effect was found. For treatment of irritable bowel syndrome, the effective rate of live combined Bifidobacterium, Lactobacillus and Enterococcus capsules was 56.8% in the second week, 74.3% in the fourth week and 73.0% in the sixth week. Single symptom was improved, especially in abdominal pain and stool character. The probiotica containing live combined Bifidobacterium, Lactobacillus and Enterococcus could increase bifidobacterium count （P〈0.01） and lactobacillus count （P〈0.05）; decrease bacteroides count （P〈0.05） and enterococci count （P〈0.01）; No obvious changes were observed in clostridium diffcile colonitis and enterobacteriaceae （P〉0.05）. Conclusion： The result of the study indicated that the administration of live combined Bifidobacterium, Lactobacillus and Enterococcus improved the symptom of irritable bowel syndrome and that there was a gradual increase of this effect. Thereafter conditions remained stable for 2 weeks. That improvement may be associated with alterations in gastrointestinal flora.

Probiotics and the gastrointestinal tract:Where are we in 2005?

Probiotic agents are live microbes or components of microbes that have a positive effect on the host. They exert their action through interplay with the immune system of the host. Some of this effect is local and some is systemic. The full story is yet to be discovered. Probiotics have a definite positive effect on rotavirus diarrhea, post antibiotic diarrhea and pouchitis. Their exact role in inflammatory bowel disease, irritable bowel syndrome, other forms of infectious diarrhea, and prevention of cancer is yet to be determined. This review summarizes the data about probiotics in these conditions.

Preventative effects of a probiotic, Lactobacillus salivarius ssp. salivarius, in the TNBS model of rat colitis

AIM： To investigate the intestinal anti-inflammatory effect and mechanism of a probiotic Lactobacillus salivarius ssp. salivariusCECT5713 in the TNBS model of rat colitis. METHODS： Female Wistar rats （180-200 g） were used in this study. A group of rats were administered orally the probiotic L. salivarius ssp. salivarius （5 × 10^8 CFU suspended in 0.5 mL of skimmed milk） daily for 3 wk. Two additional groups were used for reference, a non-colitic and a control colitic without probiotic treatment, which received orally the vehicle used to administer the probiotic. Two weeks after starting the experiment, the rats were rendered colitic by intracolonic administration of 10 mg of TNBS dissolved in 0.25 mL of 500 mL/L ethanol. One week after colitis induction, all animals were killed and colonic damage was evaluated both histologically and biochemically. The biochemical studies performed in colonic homogenates include determination of myeloperoxidase （MPO） activity, glutathione （GSH） content, leukotriene B4 （LTB4） and tumor necrosis factor α （TNF-α） levels, as well as inducible nitric oxide synthase （iNOS） expression. In addition, the luminal contents obtained from colonic samples were used for microbiological studies, in order to determine Lactobacilli and Bifidobacteria counts. RESULTS： Treatment of colitic rats with L. salivarius ssp. salivarius resulted in amelioration of the inflammatory response in colitic rats, when compared with the corresponding control group without probiotic treatment. This antiinflammatory effect was evidenced macroscopically by a significant reduction in the extent of colonic necrosis and/or inflammation induced by the administration of TNBS/ethanol （2.3±0.4 cm vs3.4±0.3 cm in control group, P〈0.01） and histologically by improvement of the colonic architecture associated with a reduction in the neutrophil infiltrate in comparison with non-treated colitic rats. The latter was confirmed biochemically by a significant reduction of colonic MPO activity （105.3±26.0 U/g vs 180.6±21.9 U/g, P〈0.05）, a marker of neutrophil infiltration. The beneficial effect was associated with an increase of the colonic GSH content （1 252±42 nmol/g vs i 087±51 nmol/g, P〈0.05）, which is depleted in colitic rats, as a consequence of the oxidative stress induced by the inflammatory process. In addition, the treatment of colitic rats with L. salivarius resulted in a significant reduction of colonic TNF-（~ levels （509.4±68.2 pg/g vs782.9±60.1 pg/g, P〈0.01） and in a lower colonic iNOS expression, when compared to TNBS control animals without probiotic administration. Finally, treated colitic rats showed higher counts of Lactobacilli species in colonic contents than control colitic rats, whereas no differences were observed in Bifidobacteria counts. CONCLUSION： Administration of the probiotic L. salivarius ssp. salivarius CECT5713 facilitates the recovery of the inflamed tissue in the TNBS model of rat colitis, an effect associated with amelioration of the production of some of the mediators involved in the inflammatory response in the intestine, such as cytokines, including TNF-α and NO. This beneficial effect could be ascribed to its effect on the altered immune response that occurs in this inflammatory condition.

Probiotic bacteria change Escherichia coli-induced gene expression in cultured colonocytes:Implications in intestinal pathophysiology

AIM: To investigate the change in eukaryotic gene expression profile in Caco-2 cells after infection with strains of Escherichia coli and commensal probiotic bacteria. METHODS: A 19 200 gene/expressed sequence tag gene chip was used to examine expression of genes after infection of Caco-2 cells with strains of normal flora E. coli,Lactobacillus plantarum,and a combination of the two. RESULTS: The cDNA microarray revealed up-regulation of 155 and down-regulation of 177 genes by E. coli . L. plantarum up-regulated 45 and down-regulated 36 genes. During mixed infection,27 genes were up-regulated and 59 were down-regulated,with nullification of stimulatory/inhibitory effects on most of the genes. Expression of several new genes was noted in this group. CONCLUSION: The commensal bacterial strains used in this study induced the expression of a large number of genes in colonocyte-like cultured cells and changed the expression of several genes involved in important cellular processes such as regulation of transcription,protein biosynthesis,metabolism,cell adhesion,ubiquitination,and apoptosis. Such changes induced by the presence of probiotic bacteria may shape the physiologic and pathologic responses they trigger in the host.

Potentially probiotic bacteria induce efficient maturation but differential cytokine production in human monocyte-derived dendritic cells

AIM： To analyze the ability of nine different potentially probiotic bacteria to induce maturation and cytokine production in human monocyte-derived dendritic cells （moDCs）. METHODS： Cytokine production and maturation of moDCs in response to bacterial stimulation was analyzed with enzyme-linked immunosorbent assay （ELISA） and flow cytometric analysis （FACS）, respectively. The kinetics of mRNA expression of cytokine genes was determined by Northern blotting. The involvement of different signaling pathways in cytokine gene expression was studied using specific pharmacological signaling inhibitors. RESULTS： All studied bacteria induced the maturation of moDCs in a dose-dependent manner. More detailed analysis with S. thermophilus THS, B. breve Bb99, and L. lactis subsp, cremoris ARH74 indicated that these bacteria induced the expression of moDC maturation markers HLA class Ⅱ and CD86 as efficiently as pathogenic bacteria. However, these bacteria differed in their ability to induce moDC cytokine gene expression. S. thermophilus induced the expression of pro-inflammatory （TNF-α, IL-12, IL-6, and CCL20） and Thl type （IL-12 and IFN-γ） cytokines, while B. breve and L. lactis were also potent inducers of antiinflammatory IL-10. Mitogen-activated protein kinase （MAPK） p38, phosphatidylinositol 3 （PI3） kinase, and nuclear factor-kappa B （NF-κB） signaling pathways were shown to be involved in bacteria-induced cytokine production. CONCLUSION： Our results indicate that potentially probiotic bacteria are able to induce moDC maturation, but their ability to induce cytokine gene expression varies significantly from one bacterial strain to another,

Probiotic intervention has strain-specific anti-inflammatory effects in healthy adults

AIM： To evaluate the effects of three potentially anti-inflammatory probiotic bacteria from three different genera on immune variables in setting based on previous in cytokine responses. healthy adults in a clinical vitro characterization of METHODS： A total of 62 volunteers participated in this randomized, double-blind and placebo-controlled parallel group intervention study. The volunteers were randomized to receive a milk-based drink containing either Lactobacillus rhamnosus GG （LGG）, Bifidobacterium animalis ssp. lactis Bb12 （Bb12）, or Propionibacterium freudenreichii ssp. shermanii JS （PJS） or a placebo drink for 3 wk. Venous blood and saliva samples were taken at baseline and on d 1, 7 and 21. Fecal samples were collected at baseline and at the end of intervention. RESULTS： The serum hsCRP expressed as the median AUC0-21 （minus baseline） was 0.018 mg/L in the placebo group, -0.240 mg/L in the LGG group, 0.090 mg/L in the Bb12 group and -0.085 mg/L in the PJS group （P = 0.014）. In vitro production of TNF-α from in vitro cultured peripheral blood mononuclear cells （PBMC） was significantly lower in subjects receiving LGG vs placebo. IL-2 production from PBMC in the Bb12 group was significantly lower compared with the other groups. CONCLUSION： In conclusion, probiotic bacteria have strain-specific anti-inflammatory effects in healthy adults.

Comparison of probiotics and lactulose in the treatment of minimal hepatic encephalopathy in rats

AIM: To compare the efficacy of probiotic preparation Golden Bifid and lactulose on rat experimental model of minimal hepatic encephalopathy (MHE) induced by thioactamide (TAA).METHODS: MHE was induced by intraperitoneal injection of TAA (200 mg/kg) every 24 h for two consecutive days.Thirty-six male MHE models were then randomly divided into 3 groups: TAA group (n = 12) received tap water ad libitum only; lactulose group (n = 12) and probiotics group (n = 12) were gavaged, respectively with 8 mL/kg of lactulose and 1.5 g/kg of probiotic preparation Golden Bifid (highly concentrated combination of probiotic)dissolved in 2 mL of normal saline, once a day for 8 d (from the 5th d before the experiment to the 3rd d of the experiment). The latency of brainstem auditory evoked potentials (BAEP) I was used as an objective index of MHE. The incidence of MHE, the level of serum endotoxin,ammonia, liver function and histological grade of hepatic injury of rats were examined individually.RESULTS: There were no overt HE and rat deaths in 3groups. The incidence of MHE, the levels of blood ammonia and endotoxin in TAA group, which were 83.3% (10/12),168.33±15.44 mg/dL and 0.36±0.04 EU/mL, respectively,were significantly higher than those in lactulose group,which were 33.3% (4/12), 110.25±7.39 mg/dL and 0.19±0.02 EU/mL, and probiotics group, which were 33.3% (4/12), 108.58±10.24 mg/dL and 0.13±0.03 EU/mL respectively (P ＜0.001). It showed that either probiotics or lactulose could significantly lower the level of hyperammonemia and hyper-endotoxemia, lighten centrolobular necrotic areas as well as inflammatory reaction in the liver of rats, normalize the latency of BAEP,and decrease the incidence of MHE. However, no significant differences were observed between these two groups (P ＞0.05).CONCLUSION: Probiotic compound Golden Bifid is at least as useful as lactulose for the prevention and treatment of MHE. Probiotic therapy may be a safe, natural, well-tolerated therapy appropriate for the long-term treatment of MHE.

Therapeutic effects of four strains of probiotics on experimental colitis in mice

AIM:To investigate the therapeutic effects of four strains of probiotics(E.feacalis,L.acidophilus,C.butyricum and B.adolescentis) on dextran sulphate sodium(DSS)-induced experimental colitis in Balb/c mice.METHODS:Eighty Balb/c mice were randomly divided into 8 groups.Weight-loss,fecal character,fecal occult blood and hematochezia were recorded daily.Disease activity index(DAI) scores were also evaluated everyday.Length of colon was measured and histological scores were evaluated on the 13th day.Myeloperoxidase(MPO) activity was detected.Interleukin-1(IL-1) and IL-4 expression was detected by ELISA and RT-PCR.RESULTS:The four strains of probiotics relieved the inflammatory condition of DSS-induced experimental colitis in mice.Weight loss was slowed down in all probiotics-treated mice.Even weight gain was observed by the end of probiotics treatment.The DAI and histological scores of probiotics-treated mice were lower than those of mice in the control group(1.9 ± 0.2 vs 8.6 ± 0.4,P < 0.05 for E.faecalis).The length of colon of probiotics-treated mice was longer than that of mice in the control group(10.3 ± 0.34 vs 8.65 ± 0.77,P < 0.05 for E.faecalis).The four strains of probiotics decreased the MP activity and the IL-1 expression,but increased the IL-4 expression.E.faecalis had a better effect on DSS-induced experimental colitis in mice than the other three strains.CONCLUSION:The four strains of probiotics have beneficial effects on experimental colitis in mice.E.faecalis has a better effect on DSS-induced experimental colitis in mice than the other three strains.Supplement of probiotics provides a new therapy for UC.

Characterization of a Mutant of Alteromonas aurantia A18 and Its Application in Mariculture

Mutant J61321 with enhanced siderophore production of Alteromonas aurantia AI8 was obtained after a series of chemical-physical mutageneses. It was found that the antibacterial activity against Vibrio anguillarum W-1 and siderophore production of the mutant were higher than those by the original strain A 18 which had been used in mariculture. The results of the specific assay（Csaky and Arnow methods） of siderophore showed that the sidrophore with hydroxamate group was produced by mutant J61321 and the original strain A 18, respectively, while the siderophore with catechol group was yielded by strain W-1 （Aibrio anguillarum）. Meanwhile, the siderophore yield, antibacterial activity and anti-chelator activity of strain J61321 were higher than those of its parent strain A 18.

Lactobacilli,bifi dobacteria and E.coli nissle induce pro-and anti-inflammatory cytokines in peripheral blood mononuclear cells

AIM： To investigate whether the stimulation of peripheral blood mononuclear cells （PBMNC） with the cell debris and cell extraction of different probiotic strains is similar or species specific. METHODS： Three strains of bifidobacteria, 4 strains of lactobacilli, and E. coli nissle were sonicated and centrifuged in order to divide them into cell extract and cell debris. PBMNC were separated by density gradient and incubated for 36 h with either the cell debris or the cell extract of single strains of probiotic bacteria in doses from 10^2 to 10^8 CFU/mL. Cell supernatants were taken and interleukin （IL）-10, IL-1β, and tumor necosis factor （TNF）-α were determined by ELISA. RESULTS： Depending on the species super-family, the strains had different stimulation patterns. Except for both L. casei strains, the cell extract of bitTdobacteria and/actobacilli had less stimulating capacity than cell debris, whereas the cell extract of E. coli nissle had similar stimulating properties to that of the cell debris of the strain and significantly more stimulating capacity than that of bifidobacteria and lactobacilli. The cell debris of bifidobacteria stimulated more cytokine release than the cell debris of lactobacilli. The cell debris of lactobacilli did not have a stimulating capacity when lower concentrations were used. Neither cell extraction nor cell debris had an inhibitory effect on the production of the tested cytokines by stimulated PBMNC. CONCLUSION： The incubation of probiotic strains, which have been used in clinical trials for inflammatory diseases, with immunocompetent cells leads to different species specific reactions. High IL-10 response to cell debris of bifidobacteria and E. coli nissle can be found. This corresponds to positive effects of bihdobacteria and E. coli nissle in clinical trials for inflammatory bowel disease compared to negative outcomes obtained with lactobacilli.

In vitro assessment of gastrointestinal viability of two photosynthetic bacteria,Rhodopseudomonas palustris and Rhodobacter sphaeroides

The objectives of this study were to assess the potential of two photosynthetic bacteria （PSB）, Rhodopseudomonas palustris HZ0301 and Rhodobacter sphaeroides HZ0302, as probiotics in aquaculture. The viability of HZ0301 and HZ0302 in simulated gastric transit conditions （pH 2.0, pH 3.0 and pH 4.0 gastric juices） and in simulated small intestinal transit conditions （pH 8.0, with or without 0.3% bile salts） was tested. The effects of HZ0301 and HZ0302 on the viability and permeability of intestinal epithelial cell in primary culture of tilapias, Oreochrornis nilotica, were also detected. All the treatments were deter- mined with three replicates. The simulated gastric transit tolerance of HZ0301 and HZ0302 strains was pH-dependent and correspondingly showed lower viability at pH 2.0 after 180 min compared with pH 3.0 and pH 4.0. Both HZ0301 and HZ0302 were tolerant to simulated small intestine transit with or without bile salts in our research. Moreover, there was no significant difference （P〉0.05） among three treatments including the control and the groups treated with HZ0301 or HZ0302 both in intestinal epithelial cell viability and membrane permeability, showing no cell damage. In summary, this study demonstrated that HZ0301 and HZ0302 had high capacity of upper gastrointestinal transit tolerance and were relatively safe for intestinal epithelial cells of tilapias.

Do probiotics have a therapeutic role in gastroenterology?

Several hundred species of bacteria inhabit the gut, and affect its cell biology, morphology and homeostasis. Many bacteria are however potential pathogens, especially if the integrity of the epithelial barrier is physically or functionally breached. Conversely, the interaction between host and commensal microbes can confer important health benefits. This has led to commercial and public interest in ＇probiotics＇, live microbes principally taken as food supplements. Might probiotics also be used in disease therapy？ Experimental evidence that probiotics modulate gut physiology, particularly barrier integrity and immunological function, underpins exciting new gastroenterological research. We discuss below the scientific basis for probiotic effects and present a critical perspective for their use in relation to gastrointestinal disease.

Effect of special Hungarian probiotic kefir on faecal microflora

AIM： To investigate the effect of a four-week consumption of a special Hungarian probiotic agent （Biofir） on the faecal microflora in human healthy subjects.METHODS： The effect of Biofir with 10^6/cm^3 initial germs on the faecal microflora was studied in 120 healthy volunteers （71 females, 49 males）. The traditional Russian type kefir was used as control. The various germ groups and pH values were determined in wk 2, 4 and 6.RESULTS： The number of all microbes increased during the 4-week probiotic treatment. The number of microbes increased 4,3-fold in the control group and 6.8-fold in Biofir-treated group. The probiotic kefir caused multiplication of the probiotic flora, meanwhile the undesired bacteria multiplied in the control group. No significant change of pH values of the faeces was found in both groups.CONCLUSION： The Hungarian probiotic keflr （Biofir） is capable of promoting multiplication of probiotic bacterial flora in the large bowel.

Antibiotic susceptibility of strains in Chinese medical probiotic products

Objective： To investigate the susceptibility of strains separated from probiotic products for medical purpose to 14 antimicrobial agents. Methods：The single aerobic strains were isolated from these products respectively and disc agar diffusion assay was proceeded to determine the susceptibility. Results： Probiotics tested in the study mostly showed multiresistant to the agents. Lactobacillus acidophilus LAP, LAB, Lactobacillus bulgaricus LBJ and Streptococcus therrnophilus STJ were resistant to vancomycin. Conclusion： Drug resistance exists in most of commercial probiotics. The evaluation and monitoring of safety of probiotic products for medical purpose should be paid great attention.