Lactobacillus paracasei subsp paracasei L. casei W8 suppresses energy intake acutely.

BACKGROUND: Probiotic bacteria have been shown to have various effects on the microbiota; this may also affect appetite and may help promote weight loss and maintenance. OBJECTIVE: This study was conducted to investigate the effect of Lactobacillus paracasei subsp paracasei L. casei W8 (L. casei W8) on glucagon-like peptide-1 (GLP-1) responses in an isolated pig intestine, in piglets and postprandially in humans. Additionally, the effect on subjective appetite, ad libitum energy intake, and glucose and insulin responses in humans was investigated. DESIGN: Piglets were fed with probiotics for 2 weeks and the effect on glucagon encoding gene (GCG) was investigated. An isolated pig intestine was perfused with L. casei W8 and the GLP-1 response was measured. Twenty-one subjects completed a randomized, controlled, crossover study with three arms. Each participant completed 3 test days testing the effect of low dose (LD) (10(9) CFU), high dose (HD) (10(10) CFU) L. casei W8 or placebo capsule. Subjective appetite was assessed before an ad libitum lunch was served. GLP-1, insulin and glucose concentrations were analyzed. RESULTS: Two weeks of treatment of piglets with L. casei W8 resulted in an increase in GCG expression compared to control animals (P<.05). L. casei W8 increased the GLP-1 response in the isolated pig intestine. In humans, L. casei W8 had an overall effect on energy intake (P=0.03), but no effects on subjective appetite sensation, overall glucose and insulin response and on GLP-1 release were observed (P>0.1). CONCLUSION: The probiotic bacteria L. casei W8 appears to lower food intake acutely, but the underlying mechanisms are not understood.

Characterization of the Vaginal DNA Virome in Health and Dysbiosis.

Bacterial vaginosis (BV) is characterized by a reduction in Lactobacillus (L.) spp. abundance and increased abundance of facultative anaerobes, such as Gardnerella spp. BV aetiology is not fully understood; however, bacteriophages could play a pivotal role in the perturbation of the vaginal bacterial community. We investigated the vaginal viral community, including bacteriophages and the association to the bacterial community and BV-status. Vaginal samples from 48 patients undergoing IVF treatment for non-female factor infertility were subjected to metagenomic sequencing of purified virus-like particles. The vaginal viral community was characterized and correlated with the BV-status by Nugent score, bacterial community, structure, and the presence of key vaginal bacterial species. The majority of identified vaginal viruses belonged to the class of double-stranded DNA bacteriophages, with eukaryotic viruses constituting 4% of the total reads. Clear links between the viral community composition and BV (q = 0.006, R = 0.26) as well as the presence of L. crispatus (q = 0.001, R = 0.43), L. iners, Gardnerella spp., and Atopobium vaginae were found (q < 0.002, R > 0.15). The eukaryotic viral community also correlated with BV-status (q = 0.018, R = 0.20). In conclusion, the vaginal virome was clearly linked with bacterial community structure and BV-status.

Effect of potato fiber on survival of Lactobacillus species at simulated gastric conditions and composition of the gut microbiota in vitro.

Potato fiber is a side product in starch manufacturing rich in dietary fibers such as pectin, cellulose, hemicellulose and resistant starch. So far, the beneficial properties of potato fiber have been poorly characterized. This study investigated the effect of FiberBind 400, a commercial potato fiber product, on survival of probiotic Lactobacillus strains at simulated gastric conditions and on the composition and metabolic activity of the gut microbiota, using the TIM-2 colon model. Resistant starch and native starch from potato were used as reference substrates. FiberBind 400 had an ability to improve survival of the four tested strains, Lactobacillus fermentum PCC®, L. rhamnosus LGG®, L. reuteri RC-14® and L. paracasei F-19® in a strain-dependent way. The highest effect was observed for L. fermentum PCC® and L. rhamnosus LGG®. The effect of starches on bacterial survival was insignificant. Composition of the fecal microbiota in TIM-2 fermentations was assessed by high-throughput sequencing of 16S rRNA gene amplicon. Fermentation of FiberBind 400 resulted in more diverse microbial communities compared to starches. Changes in microbial abundances specifically mediated by FiberBind 400, included increases in the genera Lachnospira, Butyrivibrio, Mogibacterium, Parabacteroides, Prevotella and Desulfovibrio, and the species B. ovatus, as well as decreases in Ruminococcus torques and unassigned Ruminococcus spp. Shifts in other bacterial populations, such as increased abundances of Oscillospira, Enterococcus, Bacteroidales, Citrobacter, along with reduction of Roseburia, Ruminococcus, and Faecalibacterium prausnitzii were not significantly different between the substrates. Cumulative production of individual short-chain fatty acids was similar between potato fiber and starches. The study demonstrated that FiberBind 400 had a potential to protect probiotic Lactobacillus strains during the passage through the gastrointestinal tract and selectively modulate the gut bacterial populations. This knowledge can support application of potato fiber as a functional food ingredient with added biological benefits.

Dietary xylo-oligosaccharide stimulates intestinal bifidobacteria and lactobacilli but has limited effect on intestinal integrity in rats.

BACKGROUND: Consumption of prebiotics may modulate gut microbiota, subsequently affecting the bacterial composition, metabolite profile, and human health. Previous studies indicate that also changes in intestinal integrity may occur. In order to explore this further we have investigated the effect of the putative prebiotic xylo-oligosaccharides (XOS) on the gut microbiota and intestinal integrity in male Wistar rats. As changes in intestinal integrity may be related to the expected bifidogenic effect of XOS, we additionally addressed effects of supplementation with a commensal Bifidobacterium pseudolongum (BIF) isolated from the same breed of laboratory rats. RESULTS: Changes in faecal and caecal bacterial composition determined by 16S rRNA gene sequencing and quantitative PCR for selected bacterial groups revealed that the overall bacterial composition did not differ markedly between the control (CON), XOS, and BIF groups, when correcting for multiple comparisons. However as hypothesised, the relative abundance of Bifidobacterium spp. was increased in XOS-fed rats as compared to CON in faecal samples after the intervention. Also Lactobacillus spp. was increased in both the XOS and BIF groups in caecum content compared to CON. Intestinal permeability determined in vivo by FITC-dextran permeability and in vitro using extracted caecum water in trans-epithelial resistance (TER) assay showed no effect on intestinal integrity in either the XOS or the BIF groups. However, the expression of occludin, which is part of the tight junction complex, was increased in the XOS group compared to the CON group. CONCLUSIONS: Supplementation with XOS or a commensal Bifidobacterium pseudolongum had very limited effects on intestinal integrity in rats as only significant change in expression of a single tight junction protein gene was found for the XOS group.