Molecular monitoring of the bacterial community structure in foal feces pre- and post-weaning.

This study assessed the time-scale variability of bacterial community structure in foal feces from birth to 365 days of age using Automated Ribosomal Intergenic Spacer Analysis (ARISA). Fecal samples were collected from five foals 2 h after birth (meconium) and in the morning at days 1, 2, 5, 10, 30, 60, 120, 179, 183, 194 and 365. The ARISA profiles were compared using an analysis of similarity (ANOSIM). Although both the age effect and the foal effect were highly significant (P < 0.010), the R-ANOSIM value for the foal effect was very low (R-ANOSIM = 0.089), while that of the age effect was much higher (R-ANOSIM = 0.309). Significant age-related changes were detected between days 0 and 2 (R-ANOSIM = 0.500), days 2 and 10 (R-ANOSIM = 0.475) and days 10 and 30 (R-ANOSIM = 0.519). No further shifts between consecutive times of sampling were detected in the bacterial community after day 30 and no changes were observed at weaning (day 180). These results show that the establishment of the intestinal bacterial community in foals is a sequential process, which reaches its climax state at around one month of age. Further studies using new generation sequencing based methods could be conducted to identify which bacterial genera are establishing in foals during the first month of life.

The transplantation of the gut microbiome of fat-1 mice protects against colonic mucus layer disruption and endoplasmic reticulum stress induced by high fat diet.

High-fat diets alter gut barrier integrity, leading to endotoxemia by impacting epithelial functions and inducing endoplasmic reticulum (ER) stress in intestinal secretory goblet cells. Indeed, ER stress, which is an important contributor to many chronic diseases such as obesity and obesity-related disorders, leads to altered synthesis and secretion of mucins that form the protective mucus barrier. In the present study, we investigated the relative contribution of omega-3 polyunsaturated fatty acid (PUFAs)-modified microbiota to alleviating alterations in intestinal mucus layer thickness and preserving gut barrier integrity. Male fat-1 transgenic mice (exhibiting endogenous omega-3 PUFAs tissue enrichment) and wild-type (WT) littermates were fed either an obesogenic high-fat diet (HFD) or a control diet. Unlike WT mice, HFD-fed fat-1 mice were protected against mucus layer alterations as well as an ER stress-mediated decrease in mucin expression. Moreover, cecal microbiota transferred from fat-1 to WT mice prevented changes in the colonic mucus layer mainly through colonic ER stress downregulation. These findings highlight a novel feature of the preventive effects of omega-3 fatty acids against intestinal permeability in obesity-related conditions.

Whole-Genome Sequencing and Annotation of Fibrobacter succinogenes HC4, Isolated from the Horse Cecum.

Fibrobacter succinogenes is a major cellulolytic bacterial species living in the large intestines of herbivores. This study reports the genome sequencing, assembly, and annotation of F. succinogenes HC4 (DSM 33656), a strain isolated from horse cecal contents. The genome comprised a total of 3.74 Mbp, with a G+C content of 48.96%.

Biomarkers for monitoring the equine large intestinal inflammatory response to stress-induced dysbiosis and probiotic supplementation.

Large intestine barrier disturbances can have serious consequences for the health of horses. The loss of mucosal integrity that leads to increased intestinal permeability may result from a local inflammatory immune response following alterations of the microbiota, known as dysbiosis. Therefore, our research aimed to identify noninvasive biomarkers for studying the intestinal permeability and the local inflammatory immune response in horses. Regarding the biomarkers used in other mammalian species, we measured the concentrations of lipopolysaccharides (LPS), reflected by 3-OH C14, C16, and C18 fatty acids, in blood, and fecal secretory immunoglobulin-A (SIgA). These biomarkers were evaluated in two trials including 9 and 12 healthy horses, which developed large intestinal dysbiosis experimentally induced by 5 d of antibiotic administration (trimethoprim sulfadiazine [TMS]) or 5 d of abrupt introduction of high starch levels (barley) into the diet. Horses were either control or supplemented with Lactobacillus acidophilus, Ligilactobacillus salivarius, and Bifidobacterium lactis. Correlations were performed between biomarkers and fecal bacterial diversity, composition, and function. No significant interaction between day and supplementation, or supplementation effect were observed for each biomarker. However, with the dietary stressor, a significant increase in blood concentrations of 3-OH C16 (P = 0.0125) and C14 (P = 0.0252) fatty acids was measured 2 d after the cessation of barley administration. Furthermore, with the antibiotic stressor, blood levels of 3-OH C16 progressively increased (P = 0.0114) from the first day to 2 d after the end of TMS administration. No significant day effect was observed for fecal SIgA concentrations for both stressors. These results indicate that both antibiotic- and diet-induced dysbiosis resulted in a local translocation of LPS 2 d after the cessation of the stressor treatments, suggesting an impairment of intestinal permeability, without detectable local inflammation. Blood LPS and fecal SIgA concentrations were significantly correlated with several bacterial variations in the large intestine, which are features of antibiotic- and diet-induced dysbiosis. These findings support the hypothesis that a relationship exists between dysbiosis and the loss of mucosal integrity in the large intestine of horses.

Horses can suffer from intestinal barrier disruption leading to permeability associated with local inflammation, which can result in discomfort and even disease. Intestinal barrier disruption may be a consequence of microbiota disturbances in the large intestine. Therefore, this study investigated the use of blood and fecal biomarkers for noninvasively assessing intestinal barrier permeability and inflammatory responses to microbial alterations. Two biomarkers were evaluated in healthy horses that were subjected to antibiotic- and diet-induced large intestine bacterial disturbances. Notably, the blood levels of the biomarkers increased 2 d after the cessation of both treatments, reflecting an abnormal intestinal barrier permeability. By contrast, the levels of fecal biomarker detected did not indicate the presence of inflammation. However, levels of the two biomarkers were significantly correlated with several bacterial variations in the feces, supporting the hypothesis that a relationship exists between microbiota disturbances and intestinal barrier disruption in the large intestine of horses.