Intestinal Lactobacilli Research Articles

Interaction between chicken intestinal microbiota and protein digestion

The different sections of the broiler chicken intestinal tract are inhabited by specialist microbiota adapted to the physicochemical conditions, host physiology and available nutrients of the specific habitat. The small intestine is dominated by lactic acid bacteria which have complex nutrient requirements resembling those of the chicken host itself. Lactobacilli are unable to synthesise amino acids for their anabolism and are therefore highly dependent on amino acid availability in the growth environment. Thus, in the small intestine there is competition for amino acids between the microbiota and the chicken host. According to rough estimates, lactobacilli in the small intestine may assimilate 3–6% of total dietary amino acids. If the protein is highly digestible and amino acids are largely absorbed in the upper small intestine, where bacterial growth is suppressed, the proportion captured by the host may be higher. Exogenous enzymes which promote protein digestion are also likely to provide a competitive advantage to the chicken, offering less growth potential for amino acid-dependent bacteria.Protein escaping the ileum comprises resistant protein of dietary origin, protein assimilated to intestinal bacteria and endogenous protein synthesised and secreted by the host, the latter synthesised in host tissues from dietary amino acids and thus representing true endogenous protein. Activities of small intestinal bacteria affect the size of the microbial protein fraction and also the production of endogenous proteins originating from mucin, epithelial cells and antibodies.Ileal bypass protein is subject to fermentation by putrefactive bacteria in the caecum. Putrefaction produces many harmful and toxic compounds, which in high concentrations may have adverse effects on chicken growth and performance. The protein fermentation products include amines, indoles, phenols, cresol and ammonia, which can all negatively affect host or cell health. All actions to reduce the amount of ileal bypass protein potentially also reduce production of toxic protein fermentation metabolites in the caecum. Enzymes which facilitate protein digestion in the upper intestine and soluble carbohydrates resistant to ileal digestion both reduce caecal putrefaction. In the distal intestine, saccharolytic fermentation is preferred and putrefaction accelerates only when utilisable carbohydrates are depleted. Soluble oligo- and polysaccharides are produced in situ by non-starch polysaccharide degrading enzymes and can also be added directly to the diet as health-promoting prebiotics.

Functional in vitro screening of Lactobacillus strains isolated from Tunisian camel raw milk toward their selection as probiotic

Tweenty probiotic lactic acid bacteria (LAB) strains from Tunisian camel raw milk were identified among a collection of 177 isolates. The selected strains were able to tolerate pH 2, pepsin, pancreatin and bile salts, as restrictive criteria for probiotic potential. LAB strains were identified using 16S rRNA gene sequencing. Fourteen isolates belonged to the species Lactobacillus fermentum and six to Lactobacillus plantarum. None of this LAB showed mucin degradation or hemolytic activity, while proving resistant to a series of clinically antibiotics. All strains have antibacterial activity against Listeria monocytogenes, Staphylococcus aureus and Escherchia coli. However, only 18 strains inhibited Salmonella thyphimirium. The L. fermentum strains showed an important level of adhesion to human Caco-2 and HT29-MTX epithelial cells. Our work suggests that camel raw milk is valuable source of probiotic bacteria with functional characters of intestinal lactobacilli. These bacteria may be further used in probiotic applications.

Biological Activity of Japanese Quince Extract and Its Interactions with Lipids, Erythrocyte Membrane, and Human Albumin.

The aim of the study was to determine in vitro biological activity of fruit ethanol extract from Chaenomeles speciosa (Sweet) Nakai (Japanese quince, JQ) and its important constituents (−)-epicatechin (EC) and chlorogenic acid (CA). The study also investigated the structural changes in phosphatidylcholine (PC) liposomes, dipalmitoylphosphatidylcholine liposomes, and erythrocyte membranes (RBC) induced by the extract. It was found that the extract effectively inhibits oxidation of RBC, induced by 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH), and PC liposomes, induced by UVB radiation and AAPH. Furthermore, JQ extract to a significant degree inhibited the activity of the enzymes COX-1 and COX-2, involved in inflammatory reactions. The extract has more than 2 times greater activity in relation to COX-2 than COX-1 (selectivity ratio 0.48). JQ extract stimulated growth of the beneficial intestinal bacteria Lactobacillus casei and Lactobacillus plantarum. In the fluorimetric method by means of the probes Laurdan, DPH and TMA-DPH, and 1H-NMR, we examined the structural changes induced by JQ and its EC and CA components. The results show that JQ and its components induce a considerable increase of the packing order of the polar heads of lipids with a slight decrease in mobility of the acyl chains. Lipid membrane rigidification could hinder the diffusion of free radicals, resulting in inhibition of oxidative damage induced by physicochemical agents. JQ extract has the ability to quench the intrinsic fluorescence of human serum albumin through static quenching. This report thus could be of huge significance in the food industry, pharmacology, and clinical medicine.

Efficacy of oral Bifidobacterium bifidum ATCC 29521 on microflora and antioxidant in mice.

This study aimed to examine whether Bifidobacterium bifidum ATCC 29521, a species of colonic microflora in humans, is involved in the intestinal tract of mice. This study was also conducted to determine the antioxidant activity of this species by evaluating different microbial populations and reactive oxygen species isolated from feces and intestinal contents for 28 days of oral administration. Microbial diversities were assessed through bacterial culture techniques, PCR-DGGE, and real-time PCR. This study showed that the intake of B. bifidum ATCC 29521 significantly (p < 0.05) improved the ecosystem of the intestinal tract of BALB/c mice by increasing the amount of probiotics (Lactobacillus intestinalis and Lactobacillus crispatus) and by reducing unwanted bacterial populations (Enterobacter, Escherichia coli). Antioxidative activities of incubated cell-free extracts were evaluated through various assays, including the scavenging ability of DPPH radical (64.5% and 67.54% (p < 0.05), respectively, at 21 days in nutrients and 28 days in MRS broth), superoxide anion, and hydroxyl radical (85% and 61.5% (p < 0.05), respectively, at intestinal contents in nutrients and 21 days in MRS broth). Total reducing power (231.5 μmol/L (p < 0.05), 14 days in MRS broth) and mRNA level of genes related to oxidative stress were also determined. Results indicated that B. bifidum ATCC 29521 elicits a beneficial effect on murine gut microbiota and antioxidant activities compared with the control samples. This species can be considered as a potential bioresource antioxidant to promote health. Bifidobacterium bifidum ATCC 29521 may also be used as a promising material in microbiological and food applications.

Lactobacilli with probiotic potential in the prairie vole (Microtus ochrogaster).

BackgroundRecent research suggests integration of the intestinal microbiota in gut-brain communication which could lead to new approaches to treat neurological disorders. The highly social prairie voles are an excellent model system to study the effects of environmental factors on social behavior. For future studies on the role of probiotics in ameliorating disorders with social withdrawal symptoms, we report the characterization of intestinal Lactobacillus isolates with probiotic potential from voles.Methods and results30 bacterial strains were isolated from the vole intestine and found to be distinct but closely related to Lactobacillus johnsonii using 16S rRNA gene sequencing and Random Amplification of Polymorphic DNA fingerprinting. In vitro characterizations including acid and bile tolerance, antimicrobial effects, antibiotic susceptibility, and adherence to intestinal epithelial cells were performed to assess the probiotic potential of selected strains. Since previous studies revealed that mercury ingestion triggers social deficits in voles, mercury resistance of the probiotic candidates was evaluated which could be an important factor in preventing/treating these behavioral changes.ConclusionsThis study demonstrates that lactobacilli with probiotic potential are present in the vole intestine. The Lactobacillus isolates identified in this study will provide a basis for the investigation of probiotic effects in the vole behavioral model system.Electronic supplementary materialThe online version of this article (doi:10.1186/s13099-015-0082-0) contains supplementary material, which is available to authorized users.

Effect of Dietary Supplementation of Red Ginseng By-product on Laying Performance, Blood Biochemistry, Serum Immunoglobulin and Microbial Population in Laying Hens.

This study was carried out to investigate the effect of dietary supplementation of red ginseng by-product (RGB) on the laying performance, blood biochemistry, and microbial population in laying hens. A total of 120 Hy-Line Brown laying hens (75 weeks old) were randomly allotted to 1 of 3 dietary treatments with 4 replicates per treatment. A commercial-type basal diet was prepared, and 2 additional diets were prepared by supplementing 5.0 or 10.0 g/kg of RGB to the basal diet at the expense of corn. The diets were fed to hens on an ad libitum basis for 4 weeks. There were no differences in feed intake, egg weight, and feed conversion ratio during 4 weeks of the feeding trial. However, hen-day egg production was significantly greater (p<0.05) for the RGB treatment groups than that for the basal treatment group. There were no differences in triglyceride, aspartate aminotransferase, and alanine aminotransferase during the 4-week feeding trial. However, RGB supplementation increased (p<0.05) the serum immunoglobulin G (IgG) and IgM content compared with basal treatment group. The total cholesterol was lower (p<0.05) in the RGB treatments groups than that in the basal treatment group. The intestinal Lactobacillus population was greater (p<0.05) for the RGB treatments groups than that for the basal treatment group. However, the numbers of Salmonella and Escherichia coli were not different among dietary treatments. During the entire experiment, there was no significant difference in egg quality among all the treatments. In conclusion, in addition to improving hen-day production, there were positive effects of dietary RGB supplementation on serum immunoglobulin and cholesterol levels in laying hens.

Comparison of culture-dependent and independent approaches to characterize fecal bifidobacteria and lactobacilli

Different culture-dependent and independent methods were applied to investigate the population of bifidobacteria and lactobacilli in the feces of five healthy subjects. Bacteria were isolated on MRS, a complex medium supporting growth of lactobacilli and bifidobacteria, and on three selective media for bifidobacteria and two for lactobacilli. Taxonomic characterization of the isolates was carried out by RAPD-PCR and partial 16S sequencing. The selectivity of genus-specific media was also investigated by challenging colonies from MRS plates to grow onto each medium. In parallel, a quantitative and qualitative description of bifidobacteria and lactic acid bacteria was obtained by FISH, qPCR, TRFLP, and 16S rRNA gene sequencing.Bifidobacteria did not fail to grow on their specific media and were easily isolated and enumerated, showing comparable quantitative data among culture-dependent and -independent techniques. The Bifidobacterium species identified on plates and those extracted from TRFLP and 16S rRNA gene sequencing were mostly overlapping.Selective media for lactobacilli gave unsuitable results, being too stringent or too permissive. The quantification of lactobacilli through selective plates, qPCR, FISH, and 16S rRNA gene sequencing gave unreliable results. Therefore, unlike bifidobacteria, intestinal lactobacilli are still problematic in terms of quantification and accurate profiling at level of species and possibly of strains by both culture-dependent and culture-independent techniques.

New insights into the impact of Lactobacillus population on host-bacteria metabolic interplay.

We aimed at evaluating the association between intestinal Lactobacillus sp. composition and their metabolic activity with the host metabolism in adult and elderly individuals. Faecal and plasma metabolites were measured and correlated to the Lactobacillus species distribution in healthy Estonian cohorts of adult (n = 16; < 48 y) and elderly (n = 33; > 65 y). Total cholesterol, LDL, C-reactive protein and glycated hemoglobin were statistically higher in elderly, while platelets, white blood cells and urinary creatinine were higher in adults. Aging was associated with the presence of L. paracasei and L. plantarum and the absence of L. salivarius and L. helveticus. High levels of intestinal Lactobacillus sp. were positively associated with increased concentrations of faecal short chain fatty acids, lactate and essential amino acids. In adults, high red blood cell distribution width was positively associated with presence of L. helveticus and absence of L. ruminis. L. helveticus was correlated to lactate and butyrate in faecal waters. This indicates a strong relationship between the composition of the gut Lactobacillus sp. and host metabolism. Our results confirm that aging is associated with modulations of blood biomarkers and intestinal Lactobacillus species composition. We identified specific Lactobacillus contributions to gut metabolic environment and related those to blood biomarkers. Such associations may prove useful to decipher the biological mechanisms underlying host-gut microbial metabolic interactions in an ageing population.

Effect of a multispecies lactobacillus formulation as a feeding supplement on the performance and immune function of piglets

Lactobacilli are essential members of the swine intestinal microbiota, with proposed health promoting effects. There is a reduction in the abundance of intestinal lactobacilli around weaning; this has been considered to predispose piglets to gut disturbances, e.g. diarrhea. Therefore, dietary supplementation with lactobacilli may help in maintaining better host health around weaning. In this study, we assessed the efficacy of a bacterial supplement containing six strains of the genus Lactobacillus in a feeding trial conducted in recently weaned pigs. Twenty piglets were divided into two groups (n=10) based on litter origin. Piglets in the supplementation group were fed the lactobacilli mixture (total cell count 1×1010) daily for three weeks, while those in the control group were provided with a probiotic-free placebo. The aim of this study was to evaluate the intestinal survivability of the feeding strains, as well as the effects of the supplementation on the performance of the piglets. Furthermore, the expression of selected cytokines was analyzed in the gut mucosa. The main effect of the lactobacilli supplementation observed was immunomodulation in the piglet intestine, especially in the large intestine. Upregulated expressions of IL-4 and IFN-α were detected in the cecum, with downregulated expressions of IL-8 and TNF in the colon of the supplementation group. In addition, supplementation downregulated the expression of TGF-β1 in the jejunum, ileum and colon. An increased total bacterial number was detected in the jejunum of the supplementation group, but no change in the intestinal digesta pH or in the numbers of lactobacilli was induced by the supplementation. In addition, the strains which had been supplied could not be isolated from feces, indicating that they had been unable to colonize the piglet intestine in significant numbers. The lactobacilli supplementation had no effect on the weight gain or the intestinal mucosal morphology of the piglets. While the lactobacilli supplement used in this study failed to achieve a growth-enhancing effect, and the supplemented strains appeared to have a limited ability to compete with the indigenous intestinal microbiota of piglets, the supplement evoked immunomodulatory properties in the piglet intestine.

Effects of acidified drinking water on performance, carcass, immune response, jejunum morphology, and microbiota activity of broiler chickens fed diets containing graded levels of threonine

A 2×4 factorial arrangement of treatments was used to investigate the effects of 2 levels of an acidifier supplement (0 or 350mL/1000L) in drinking water on growth performance, carcass, immune response, intestinal microbial flora, and jejunum morphology of broiler chickens fed diets based on 4 levels of dietary Thr (100, 110, 120, and 130% of the requirements). A total of 320 broiler chickens were assigned to 8 treatments with 4 replicate pens of 10 broiler chickens per pen. Growth performance traits, including daily weight gain, feed intake, and feed conversion ratio (FCR), were recorded. The broiler chickens immunized against Newcastle disease virus (NDV) at 8d of age. Blood samples were drawn from the wing vein 7 and 14d after vaccination for the determination of primary and secondary antibody responses. In addition, blood samples were collected in tubes containing anticoagulant to determine the number of heterophil (H) and lymphocyte (L). At the end of the experiment, 4 broiler chickens per treatment were selected and killed, and, then, the relative weights of carcass parts, jejunum morphology, and intestinal microbial population were determined. The results showed that broiler chickens received acidified drinking water (ADW) had greater (P<0.05) feed intake (28.51 vs. 27.30g/chicken/d) and weight gain (20.01 vs. 19.26g/chicken/d) than those received without water additive during the starter period. Neither Thr nor ADW had any effect on any carcass traits of broiler chickens. Heterophil count and H to L ratio were increased (35.87 and 0.63%, respectively) and lymphocyte count was decreased (56.50%) in broiler chickens fed diets containing 110% threonine (P<0.05). However, antibody titer against NDV was not influenced by experimental treatments. In the jejunum, the villus width (136.8µm) and crypt depth (188.9µm) were greater and the ratio of VH to CD was lower (6.50) in broiler chickens received ADW (P<0.05). Moreover, the population of Escherichia coli decreased (5.79 vs. 6.23log10 cfu/g) in broiler chickens received ADW, while lactobacilli population increased (7.45 vs. 6.90log10 cfu/g; P<0.05). However, dietary Thr had no effect on jejunum morphology and intestinal microbial population of broiler chickens. The present findings indicate that ADW improves growth performance (0–10d), jejunum morphology, and intestinal lactobacilli population of broiler chickens. In addition, the use of 110% Thr increased H to L ratio in broiler chickens. However, different graded concentrations of Thr did not alter growth performance, intestinal morphology, and microbiota activity.

Effects of rhubarb on intestinal flora and toll-like receptors of intestinal mucosa in rats with severe acute pancreatitis.

The aim of this study was to examine the effects of rhubarb on intestinal flora and toll-like receptors (TLRs) of intestinal mucosa in rats with severe acute pancreatitis (SAP). Healthy male Sprague-Dawley rats were randomly allocated into sham-operated surgical model of SAP without or with postoperative rhubarb treatment groups (7 in each group). Rats in with rhubarb group received 10% rhubarb decoction (1 mL/200 g) through tube feeding at every 8 hours during postoperative 24 hours. Serum amylase, amount of intestinal flora, and TLR2/TLR4 messenger RNA expression in intestinal mucosa were tested among 3 groups at postoperative 24 hours. TLR2 and TLR4 messenger RNA expression levels in intestinal mucosa in SAP without rhubarb group were significantly higher than those in sham-operated or SAP with rhubarb groups (P < 0.05). The amount of intestinal lactobacilli and bifidobacteria in SAP without rhubarb group were significantly fewer than in those sham-operated group (P < 0.05) but not significantly different from those in SAP with rhubarb group (P > 0.05). The amount of intestinal Escherichia coli was relatively higher in SAP group than in sham-operated group (P > 0.05) but lesser in rhubarb treatment group (P > 0.05). Rhubarb might maintain the intestinal mucosal barrier through regulating intestinal flora and inhibiting intestinal inflammatory response in rats with SAP.

Effects of dietary essential oil and enzyme supplementation on growth performance and gut health of broilers challenged by Clostridium perfringens

Abstract An experiment was carried out to evaluate the effects of dietary supplemental essential oil comprising thymol and carvacrol (EO), and enzyme complex containing xylanase, glucanase and mannanase as major components (CSM) on Clostridium perfringens challenged model in broilers. A total of 648 1-d-old female broiler chicks were assigned to eight groups. A 2 × 2 × 2 factorial arrangement of treatments was used in a randomized complete block design to study the effects of essential oil supplementation (with or without EO 60 mg/kg diet), enzymes addition (with or without CSM 500 mg/kg diet), pathogen challenge (with or without C. perfringens challenge from d 14 to 20), and the interactive effects. A pelleted high NSP wheat–soybean meal basal diet was formulated to meet nutrient requirements recommended by NRC (1994) . Body weight, feed intake, and feed to gain ratio were determined on d 14, 21 and 35; ileal digesta viscosity, intestinal lesion score, ileal histomorphologic indices, bacterial population and plasma endotoxin were measured on d 21; while ileal permeability was determined from d 24 to 26. Results indicated that enzyme CSM supplementation increased body weight on d 21 and 35, improved feed to gain ratio from d 0 to 14 and 0 to 21, increased P-glycoprotein dependent efflux permeability ( P app (S–M)), decreased digesta viscosity, and lowered ileal C. perfringens and Lactobacillus colonization. CSM supplementation could also improve feed conversion ratio from d 0 to 35 and VH/CD on d 21 of C. perfringens challenged chicks, while EO supplementation increased villus height and VH/CD. C. perfringens challenge increased intestinal lesion score, C. perfringens and Lactobacillus colonization, but decreased Bifidobacterium colonization and P app (S–M). C. perfringens challenge also resulted in increased plasma endotoxin, passive transcellular permeability ( P app (M–S)), sIgA, and E. coli colonization when chicks were fed with basal diet, while EO or CSM supplementation could alleviate the alteration caused by C. perfringens infection. In conclusion, dietary enzyme CSM supplementation could benefit for growth performance and gut health, and EO could improve the gut health of C. perfringens challenged chicks.

Changes in gut microbiota in rats fed a high fat diet correlate with obesity-associated metabolic parameters.

The gut microbiota is emerging as a new factor in the development of obesity. Many studies have described changes in microbiota composition in response to obesity and high fat diet (HFD) at the phylum level. In this study we used 16s RNA high throughput sequencing on faecal samples from rats chronically fed HFD or control chow (n = 10 per group, 16 weeks) to investigate changes in gut microbiota composition at the species level. 53.17% dissimilarity between groups was observed at the species level. Lactobacillus intestinalis dominated the microbiota in rats under the chow diet. However this species was considerably less abundant in rats fed HFD (P<0.0001), this being compensated by an increase in abundance of propionate/acetate producing species. To further understand the influence of these species on the development of the obese phenotype, we correlated their abundance with metabolic parameters associated with obesity. Of the taxa contributing the most to dissimilarity between groups, 10 presented significant correlations with at least one of the tested parameters, three of them correlated positively with all metabolic parameters: Phascolarctobacterium, Proteus mirabilis and Veillonellaceae, all propionate/acetate producers. Lactobacillus intestinalis was the only species whose abundance was negatively correlated with change in body weight and fat mass. This species decreased drastically in response to HFD, favouring propionate/acetate producing bacterial species whose abundance was strongly correlated with adiposity and deterioration of metabolic factors. Our observations suggest that these species may play a key role in the development of obesity in response to a HFD.

Chronic ethanol consumption alters intestinal microbiota composition (MUC9P.746)

Abstract It is well known that chronic alcohol consumption leads to organ damage and increased susceptibility to bacterial and viral infections. Ethanol exposure in the intestinal lumen alters tight junction proteins leading to disruption of the epithelial barrier. Increased permeability in turn leads to translocation of gut-derived endotoxins causing inflammatory responses in the liver that contribute to alcoholic liver disease. Recent studies have shown that gut mucosa homeostasis is also modulated by the microbiome. Disruptions in the gut microbiome have been described for many diseases including IBD, diabetes and colon cancer. In order to gain a better understanding of the dose-dependent effects of ethanol on the gut microbiome, we performed ribosomal RNA sequencing to determine the differentially expressed bacteria in the small and large intestine in a rhesus macaque model of voluntary ethanol self-administration. In the colon we observed a 2-fold increase in heavy drinkers compared to nondrinkers in the phylum Bacteroidetes that subsequently results in a decrease in Firmicutes, the phylum containing most beneficial lactic acid bacteria. In the duodenum, jejunum, ileum and colon we found a 3-fold decrease in the commensal species Lactobacillus intestinalis and a 2-fold increase in the potential pathogenic species Prevotella copri in heavy drinkers compared to nondrinkers. These studies are likely to reveal mechanisms of ethanol-related gut dysregulation and related inflammation.

Analysis of biofilm formation by intestinal lactobacilli.

In this study, the biofilm-forming potential of intestinal Lactobacillus reuteri strains under different culture conditions was characterized by microtiter plate biofilm assays. Moreover, the spatial organization of exogenously applied L. reuteri L2/6 (a pig isolate) at specific locations in gastrointestinal tract of monoassociated mice was investigated by fluorescence in situ hybridization. We did not detect biofilm formation by tested strains in nutrient-rich de Man-Rogosa-Sharpe (MRS) medium. On the contrary, a highly positive biofilm formation was observed in medium with lower accessibility to the carbon sources and lack of salts. The results obtained confirmed the significant role of Tween 80 and the quantity and nature of the sugars in the growth medium in biofilm formation. The omission of Tween 80 in MRS medium favored the formation of biofilm. Abundant biofilm formation was detected in the presence of lactose, galactose, and glucose. However, a gradual increase in sugar concentration triggered a significant decrease in biofilm formation. In addition, conditions related to the gastrointestinal environment, such as low pH and the presence of bile and mucins, highly modulated biofilm production. This effect seems to be dependent on the specificity and properties of the medium used for cultivation. From the evidence provided by this study we conclude that the biofilm formation capacity of L. reuteri is strongly dependent on the environmental factors and culture medium used.

English

Various types of fermented dairy products exist worldwide. Their nature depends on the type of milk used, pretreatment, fermentation conditions and subsequent treatment. The fermentation of milk primarily involves lactic acid bacteria (LAB). Among these, the Klila is a hard variety cheese made by using the traditional procedures in the home, without using a starter culture. The different samples of traditional cheese (Klila) studied were collected from the rural area of the province of Djelfa. Isolates were phenotypically characterized by their capability to ferment different carbohydrates and additional biochemical tests. 132 lactic acid bacterial strains were isolated, purified and identified to all belong to the genus, Lactobacillus, their proportion were Lactobacillus plantarum (18.94%), Lactobacillus casei (18.18%), Lactobacillus fermentum (21.97%), Lactobacillus acidophilus (12.88%), Lactobacillus brevis (14.39%), Lactobacillus alimentarus (03.03%), Lactobacillus intestinalis (06.06%) and Lactobacillus helveticus (04.56%). These lactic acid bacteria were isolated against Staphylococcus aureus. Isolates L. fermentum, L. intestinalis and L. acidophilus were selected for their strong bactericidal activity against S. aureus. Key words: Klila, lactic acid bacteria, identification, characteristics, Lactobacillus, Staphylococcus aureus.

Effects of Enterococcus faecium DSM 7134 supplementation in different energy and crude protein density diets on ileal amino acid digestibility and intestinal shedding of lactobacilli and Escherichia coli in finishing pigs

This experiment was conducted to determine the efficacy of Enterococcus faecium DSM 7134, in different energy and crude protein density diets on ileal amino acid digestibility and intestinal microbial shedding in finishing pigs. Twelve finishing barrows (initial body weight=75.1±3.44kg) were surgically equipped with a T-cannula in the distal ileum and arranged in a triplicate 4×4 Latin square design with four diets and four periods. Diets were formulated with two levels of nutrient density (high energy: 14.6MJ/kg ME or low energy: 14.2MJ/kg ME) and two levels of probiotic (0 or 1.0×109cfu/kg diet). The coefficient of apparent ileal digestibility (CAID) of crude protein (CP), gross energy (GE), and most of the indispensable amino acids (AA) except for His-Phe and Val were increased (P<0.05) by 5.3%, 6.0%, and 5.2–7.2% in pigs fed the E. faecium compared with non-supplemented groups. The CAID of Cys and Gly was 6.2% and 7.0% greater (P<0.05) in E. faecium groups than non-supplemental groups. Ileal and fecal Lactobacilli counts were increased (P<0.05) by 19.9% and 16.6%, and Escherichia coli counts were decreased (P<0.05) by 8.9% and 9.5% in pigs fed the diets supplemented with probiotic, respectively. The CAID of CP, Lys-Met-Thr-Leu-Ile-Cys-Gly as well as the lactobacilli counts were increased in both E. faecium treatments, but values were increased higher in the high density diet. In conclusion, dietary supplementation with 1.0×109cfu/kg of E. faecium DSM 7134 exerted beneficial effects on the CAID of CP and AA and intestinal lactobacilli shedding, especially was administrated in high energy and crude protein density diets.

Potentially probiotic and bioprotective lactic acid bacteria starter cultures antagonise the Listeria monocytogenes adhesion to HT29 colonocyte-like cells.

The capability of five lactic acid bacteria (LAB) to counteract the adhesion of Listeria monocytogenes to the epithelial intestinal cell line HT29 was studied. The highest adhesion ability to HT29 was achieved by the intestinal strain Lactobacillus rhamnosus CTC1679, followed by the meat-derived strains Lactobacillus sakei CTC494 and Enterococcus faecium CTC8005. Surprisingly, the meat strains showed significantly better adhesion to HT29 than two faecal isolates of Lactobacillus casei and even significantly higher than the reference strain L. rhamnosus GG. Additionally, the anti-listerial, bacteriocin-producer starter culture L. sakei CTC494 was able to significantly reduce the adhesion of L. monocytogenes to HT29 in experiments of exclusion, competition and inhibition. The performance was better than the faecal isolate L. rhamnosus CTC1679. Our results reinforce the fact that the ability of LAB to interact with a host epithelium model, as well as to antagonise with foodborne pathogens, is a strain-specific characteristic. Additionally, it is underlined that this trait is not dependent on the origin of the bacterium, since some food LAB behave better than intestinal ones. Therefore, the search for novel strains in food niches is a suitable approach to find those with potential health benefits. These strains are likely pre-adapted to the food environment, which would make their inclusion in the formulation of probiotic foods more feasible.

Probiotics: Healthy bugs and nourishing elements of diet.

The use of probiotics is based on the concept that adding the right live microbes to the complex human system can result in physiological benefits. The benefit of fermented milk in human diet has been acknowledged since Vedic times; however, the scientific interest in this field was evoked by Ellie Metchinkoff who recommended that people should consume fermented milk containing lactobacilli to prolong their lives, as accelerated aging is due to autointoxication caused by the toxins produced by the gut microflora. They have been used to improve gastrointestinal health and their attractiveness has evinced interest to study their role in the promotion of oral health also. Studies have been widely carried out to establish the role of intestinal lactobacilli as probiotic to treat various gastrointestinal disorders, but only limited studies are available on the oral use of probiotics. The probiotic products usually contain lactobacilli and bifidobacteria, and their demand in the market is growing day by day. This paper provides an overview of various studies in the literature that emphasize on the role of probiotics to combat oral diseases and encourages more research in this field.

Effects of dietary vitamin K levels on growth performance, enzyme activities and antioxidant status in the hepatopancreas and intestine of juvenile Jian carp (Cyprinus carpiovar. Jian)

A total of 1400 juvenile Jian carp (Cyprinus carpio var. Jian) (8.93 ± 0.03 g) were fed diets containing graded levels of vitamin K at 0.027 (basal diet), 1.52, 3.02, 4.51, 6.02 and 7.52 mg kg−1 diet for 60 days to investigate the effects of vitamin K on growth, enzyme activities and antioxidant capacity in the hepatopancreas and intestine. Percentage weight gain (PWG), feed intake and feed efficiency of fish were improved by vitamin K. Activities of trypsin, chymotrypsin, amylase and lipase in the intestine and hepatopancreas and Na+, K+-ATPase, creatine kinase, alkaline phosphatase and gamma-glutamyl transpeptidase in the intestine were increased by vitamin K. Malondialdehyde and protein carbonyl contents in the hepatopancreas and intestine were decreased with vitamin K supplements. Certain level of vitamin K increased antihydroxyl radical, antisuperoxide anion, superoxide dismutase, catalase, glutathione-S-transferase, glutathione peroxidase and glutathione reductase activities and glutathione contents in the hepatopancreas and intestine. Intestinal Lactobacillus, E. coli and Aeromonas were changed with vitamin K supplements. Together, these results indicate that vitamin K improved fish growth, digestive and absorptive ability, and anti-oxidant capacity. The dietary vitamin K requirement of juvenile Jian carp (8.93–73.7 g) based on PWG was 3.13 mg kg−1 diet.