Endogenous Small Intestinal Microbiome Determinants of Transient Colonization Efficiency by Bacteria from Fermented Dairy Products; A Randomized Controlled Trial

BackgroundThe effects of fermented food consumption on the small intestine microbiome and its role on host homeostasis are largely uncharacterized as our knowledge on intestinal microbiota relies mainly on faecal samples analysis. We investigated changes in the small intestinal microbial composition and functionality, short chain fatty acid (SCFA) profiles, and on the gastro-intestinal (GI) permeability in ileostomy subjects upon the consumption of fermented milk products.ResultsWe report the results from a randomized, cross-over, explorative study where 16ileostomy subjects underwent 3, 2-week interventions periodsin which they daily consumed either milk fermented by Lacticaseibacillus rhamnosus CNCM I-3690, or milk fermented by Streptococcus thermophilus CNCM I-1630 and Lactobacillus delbrueckii subsp. bulgaricus CNCM I-1519, or a chemically acidified milk (placebo). Weperformed metataxonomic, metatranscriptomic analysis and SCFA profiling of ileostomy effluents as well as a sugar permeability test andto investigate the microbiome impact of these interventions and their potential effect on mucosal barrier function. Consumption of the intervention products significantly impacted the small intestinal microbiome composition and functionality but did not affect the SCFA levels in ileostoma effluent, or the gastro-intestinal permeability. Theimpact on microbiome composition was highly personalized,andwe identified the poorly characterized bacterial family, Peptostreptococcaceae, to be positively associated with low abundance of the ingested bacteria. Activity profiling of the microbiota revealed that carbon- versus amino acid-derived energy metabolism of the endogenous microbiome could be responsible for the individual-specific intervention effects on the small intestine microbiome composition and function.ConclusionsThe ingested bacteria are the main drivers of the intervention effect on the small intestinal microbiota composition. Their transient abundance level is highly personalized and influenced by the energy metabolism of the ecosystem that is reflected by its microbial composition (http://www.clinicaltrials.gov, ID NCT NCT02920294).

Oral Vaccination Reduces the Effects of Lawsonia intracellularis Challenge on the Swine Small and Large Intestine Microbiome

Porcine proliferative enteropathy remains one of the most prevalent diseases in swine herds worldwide. This disease is caused by Lawsonia intracellularis, an intracellular bacterial pathogen that primarily colonizes the ileum. In this study, we evaluated changes to the microbiome of the ileal mucosa, ileal digesta, cecal digesta, and feces subsequent to challenge with L. intracellularis and to an oral live vaccine against L. intracellularis. Given that gut homogenates have been used since 1931 to study this disease, we also characterized the microbial composition of a gut homogenate from swine infected with L. intracellularis that was used as challenge material. The L. intracellularis challenge led to a dysbiosis of the microbiome of both the small and large intestine marked by an increase of pathobionts including Collinsella, Campylobacter, Chlamydia, and Fusobacterium. This microbiome response could play a role in favoring L. intracellularis colonization and disease as well as potentially predisposing to other diseases. Vaccination altered both small and large intestine microbiome community structure and led to a significant 3.03 log10 reduction in the amount of L. intracellularis shed by the challenged pigs. Vaccination also led to a significant decrease in the abundance of Collinsella, Fusobacterium, and Campylobacter among other microbial changes compared with non-vaccinated and challenged animals. These results indicate that L. intracellularis infection is associated with broad changes to microbiome composition in both the large and small intestine, many of which can be mitigated by vaccination.

Promising potential of high-throughput molecular phenotyping of freshwater fishes for environmental assessment

The recent democratisation of high-throughput molecular phenotyping allows the rapid expansion of promising untargeted multi-dimensional approaches (e.g. epigenomics, transcriptomics, proteomics, metabolomics, as well as microbiome metabarcoding), that now represent innovative perspectives for environmental assessments. Indeed, when developed for ecologically relevant species, these emerging omics analyses may present valuable alternatives for the development of novel generations of ecological indicators, that in turn could provide early warnings of eco(toxico)logical impairments. This pilot study investigates the bio-indicative potential of different multi-metric tools based on different high-throughput molecular phenotyping approaches (i.e. metabarcoding of the intestine microbiome, and liver metabolomics by nuclear magnetic resonance (NMR) and liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS) on two sentinel fish species (Perca fluviatilis and Lepomis gibbosus) from a set of eight water bodies of the peri-urban area of Paris (France). We show that the LC-MS metabolome dataset allows remarkably clear separation of individuals according to the species but also according to their respective sampling lakes. Interestingly, the similar variations of Perca and Lepomis metabolomes occur locally indicating that local environmental constraints drive the observed metabolome variations beyond their obvious genetic differences. Thus, the development of such reliable molecular phenotyping for environmental monitoring constitutes a promising and innovative bio-indicative tool for environmental assessment.

Spatial heterogeneity of the shorebird gastrointestinal microbiome

The gastrointestinal tract (GIT) consists of connected structures that vary in function and physiology, and different GIT sections potentially provide different habitats for microorganisms. Birds possess unique GIT structures, including the oesophagus, proventriculus, gizzard, small intestine, caeca and large intestine. To understand birds as hosts of microbial ecosystems, we characterized the microbial communities in six sections of the GIT of two shorebird species, the Dunlin and Semipalmated Sandpiper, identified potential host species effects on the GIT microbiome and used microbial source tracking to determine microbial origin throughout the GIT. The upper three GIT sections had higher alpha diversity and genus richness compared to the lower sections, and microbial communities in the upper GIT showed no clustering. The proventriculus and gizzard microbiomes primarily originated from upstream sections, while the majority of the large intestine microbiome originated from the caeca. The heterogeneity of the GIT sections shown in our study urges caution in equating data from faeces or a single GIT component to the entire GIT microbiome but confirms that ecologically similar species may share many attributes in GIT microbiomes.

Early Postnatal Diets Affect the Bioregional Small Intestine Microbiome and Ileal Metabolome in Neonatal Pigs

Background: Breastfeeding is known to be protective against gastrointestinal disorders and may modify gut development. Although the gut microbiome has been implicated, little is known about how early diet affects the small intestine microbiome. Objective: We hypothesized that disparate early diets would promote unique microbial profiles in the small intestines of neonatal pigs. Methods: Male and female 2-d-old White Dutch Landrace pigs were either sow fed or provided dairy (Similac Advance powder; Ross Products Abbott Laboratories) or soy (Enfamil Prosobee Lipil powder; Mead Johnson Nutritionals) infant formulas until day 21. Bacterial ecology was assessed in the contents of the small intestine through the use of 16S ribosomal RNA sequencing. α-Diversity, β-diversity, and differential abundances of operational taxonomic units were assessed by ANOVA, permutational ANOVA, and negative binomial regression, respectively. Ileum tissue metabolomics were measured by LC-mass spectrometry and assessed by weighted correlation network analysis. Results: Greater α-diversity was observed in the duodena of sow-fed compared with formula-fed neonatal pigs (P < 0.05). No differences were observed in the ilea. Firmicutes represented the most abundant phylum across all diets in duodena (78.8%, 80.1%, and 53.4% relative abundance in sow, dairy, and soy groups, respectively), followed by Proteobacteria in sow (12.2%) and dairy (12.4%) groups and Cyanobacteria in soy-fed (36.2%) pigs. In contrast to those in the duodenum, Proteobacteria was the dominant phylum in the ileum, with >60% relative abundance in all of the groups. In the duodenum, 77 genera were altered by diet, followed by 48 in the jejunum and 19 in the ileum. Metabolomics analyses revealed associations between ileum tissue metabolites (e.g., acylcarnitines, 3-aminoisobutyric acid) and diet-responsive microbial genera. Conclusions: These results indicate that the neonatal diet has regional effects on the small intestine microbiome in pigs, with the most pronounced effects occurring in the duodena. Regional effects may be important factors when considering gut tissue metabolism and development in the postnatal period.