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ObjectiveData from clinical research suggest that certain probiotic bacterial strains have the potential to modulate colonic inflammation. Nonetheless, these data differ between studies due to the probiotic bacterial strains used and the poor knowledge of their mechanisms of action.DesignBy mass-spectrometry, we identified and quantified free long chain fatty acids (LCFAs) in probiotics and assessed the effect of one of them in mouse colitis.ResultsAmong all the LCFAs quantified by mass spectrometry in Escherichia coliNissle 1917 (EcN), a probiotic used for the treatment of multiple intestinal disorders, the concentration of 3-hydroxyoctadecaenoic acid (C18-3OH) was increased in EcN compared with other E. colistrains tested. Oral administration of C18-3OH decreased colitis induced by dextran sulfate sodium in mice. To determine whether other bacteria composing the microbiota are able to produce C18-3OH, we targeted the gut microbiota of mice with prebiotic fructooligosaccharides (FOS). The anti-inflammatory properties of FOS were associated with an increase in colonic C18-3OH concentration. Microbiota analyses revealed that the concentration of C18-3OH was correlated with an increase in the abundance in Allobaculum, Holdemanellaand Parabacteroides. In culture, Holdemanella biformisproduced high concentration of C18-3OH. Finally, using TR-FRET binding assay and gene expression analysis, we demonstrated that the C18-3OH is an agonist of peroxisome proliferator activated receptor gamma.ConclusionThe production of C18-3OH by bacteria could be one of the mechanisms implicated in the anti-inflammatory properties of probiotics. The production of LCFA-3OH by bacteria could be implicated in the microbiota/host interactions.

Intestinal integrity losses have been identified as a main driver for poor performance in broilers. The oral administration of markers such as iohexol is a major asset for measuring intestinal permeability (IP) alterations. The aim of the current study was to evaluate oral iohexol administration and serum levels as a quantitative measure for IP in Ross 308 broilers and to identify possible associations with histologic measurements. A total of 40, day-old broiler chickens were randomly divided into 4 groups of 10 broilers and a coccidiosis model was used to induce IP. Three challenge groups received a mixture of different field strains and concentrations of Eimeria acervulinaand Eimeria maximaat d 16, and 1 group operated as an uninfected control group. On d 20, 5 birds per group were orally administered the permeability marker iohexol at a dose of 64.7 mg/kg body weight and blood was taken 60 min after the oral gavage. On d 21 these 5 birds per group were euthanized. On d 21, 5 other birds per group were given iohexol where after blood was taken. These birds were euthanized on d 22. During necropsy, birds were scored for coccidiosis lesions and a duodenal segment was taken for histology. The Eimeriachallenge had a significant impact on the villus length, crypt depth, villus-to-crypt ratio and CD3+T-lymphocytes area percentage. Challenged birds had a significant higher concentration of serum iohexol on both sampling days, as compared to the uninfected controls. A significant correlation could be found between the serum iohexol concentration and the histologic parameters (villus length, crypt depth and villus-to-crypt ratio) on the first sampling day. This suggests that iohexol may be used as a gut permeability marker in broilers under Eimeriachallenge.

ObjectivePouchitis is the most common complication after colectomy with ileal pouch-anal anastomosis (IPAA) for UC and the risk is the highest within the 1st year after surgery. The pathogenesis is not completely understood but clinical response to antibiotics suggests a role for gut microbiota. We hypothesised that the risk for pouchitis can be predicted based on the faecal microbial composition before colectomy.DesignFaecal samples from 21 patients with UC undergoing IPAA were prospectively collected before colectomy and at predefined clinical visits at 1 month, 3 months, 6 months and 12 months after IPAA. The predominant microbiota was analysed using community profiling with denaturing gradient gel electrophoresis followed by quantitative real-time PCR validation.ResultsCluster analysis before colectomy distinguished patients with pouchitis from those with normal pouch during the 1st year of follow-up. In patients developing pouchitis, an increase of Ruminococcus gnavus(p<0.001), Bacteroides vulgatus(p=0.043), Clostridium perfringens(p=0.011) and a reduction of two Lachnospiraceaegenera (Blautia(p=0.04), Roseburia(p=0.008)) was observed. A score combining these five bacterial risk factors was calculated and presence of at least two risk factors showed a sensitivity and specificity of 100% and 63.6%, respectively.ConclusionsPresence of R. gnavus, B. vulgatusand C. perfringensand absence of Blautiaand Roseburiain faecal samples of patients with UC before surgery is associated with a higher risk of pouchitis after IPAA. Our findings suggest new predictive and therapeutic strategies in patients undergoing colectomy with IPAA.

Broilers often suffer from subclinical intestinal health problems of ill-defined etiology, which have a negative impact on performance. Macroscopic and microscopic evaluations can be used to monitor intestinal health, but since these are subjective and time-consuming, respectively, objective and easy-to-measure biomarkers are urgently needed. Faecal biomarkers can potentially be used as non-invasive, objective measures to evaluate gut health in broilers. The aim of the current study was to evaluate ovotransferrin (OVT) as a biomarker in faecal/colonic samples derived from broilers from 27 industrial farms by investigating associations between OVT, broiler performance and gut histology parameters. Eight chickens per farm were randomly selected, weighed and euthanized on day 28 of the production round. A duodenal section was collected to measure the intestinal villus structure (villus length, crypt depth) and the inflammatory status of the gut (CD3+T-lymphocytes area percentage). The coefficient of variation for the OVT (between farms; 83.45 %, within farms; 95.13 %) was high compared to the villus length (between farms; 10.91 %, within farms; 15.48 %), crypt depth (between farms; 15.91 %, within farms; 14.10 %), villus-to-crypt ratio (between farms; 22.08 %, within farms; 20.53 %) and CD3+(between farms; 36.38 %, within farms; 26.13 %). At farm level, colonic OVT was significantly associated with the average slaughter weight (p = 0.005), daily weight gain (p = 0.007) and the European production index (EPI) (p = 0.009). At broiler level, significant associations were found between colonic OVT and the villus length (p = 0.044) and between the colonic OVT and villus-to-crypt ratio (p = 0.050). These results thus show that quantifying OVT in colon can have merit for evaluation of intestinal health in broilers under field conditions.

Intestinal health is critically important for the digestion and absorption of nutrients and thus is a key factor in determining performance. Intestinal health issues are very common in high performing poultry lines due to the high feed intake, which puts pressure on the physiology of the digestive system. Excess nutrients which are not digested and absorbed in the small intestine may trigger dysbiosis, i.e. a shift in the microbiota composition in the intestinal tract. Dysbiosis as well as other stressors elicit an inflammatory response and loss of integrity of the tight junctions between the epithelial cells, leading to gut leakage. In this paper, key factors determining intestinal health and the most important nutritional tools which are available to support intestinal health are reviewed.

Galactomannans are abundant nonstarch polysaccharides in broiler feed ingredients. In broilers, diets with high levels of galactomannans have been associated with innate immune response stimulation, poor zootechnical performance, nutrient and lipid absorption, and excessive digesta viscosity. However, data about its effects on the gut microbiome are scarce. β-Mannanases are enzymes that can hydrolyze β-mannans, resulting in better nutrient utilization. In the current study, we have evaluated the effect of guar gum, a source of galactomannans, supplemented to broiler diets, either with or without β-mannanase supplementation, on the microbiota composition, in an attempt to describe the potential role of the intestinal microbiota in β-mannanase-induced gut health and performance improvements. One-day-old broiler chickens (n = 756) were randomly divided into 3 treatments: control diet, guar gum-supplemented diet (1.7%), or guar gum-supplemented diet + β-mannanase (Hemicell 330 g/ton). The zootechnical performance, gut morphometry, ileal and cecal microbiome, and short-chain fatty acid concentrations were evaluated at different time points. The guar gum supplementation decreased the zootechnical performance, and the β-mannanase supplementation restored performance to control levels. The mannan-rich diet-induced dysbiosis, with marked effects on the cecal microbiota composition. The guar gum-supplemented diet increased the cecal abundance of the genera Lactobacillus, Roseburia, Clostridium sensu stricto 1, and Escherichia-Shigella, and decreased Intestinimonas, Alistipes, Butyricicoccus, and Faecalibacterium. In general, dietary β-mannanase supplementation restored the main microbial shifts induced by guar gum to levels of the control group. In addition, the β-mannanase supplementation reduced cecal isobutyric, isovaleric, valeric acid, and branched-chain fatty acid concentrations as compared to the guar gum-supplemented diet group, suggesting improved protein digestion and reduced cecal protein fermentation. In conclusion, a galactomannan-rich diet impairs zootechnical performance in broilers and results in a diet-induced dysbiosis. β-Mannanase supplementation restored the gut microbiota composition and zootechnical performance to control levels.

ABSTRACTParatyphoid caused by Salmonella entericasubsp. entericaserovar Typhimurium is the main bacterial disease in pigeons. The ability of Salmonellaserovar Typhimurium to persist intracellularly inside pigeon macrophages results in the development of chronic carriers, which maintain the infection in the flock. In this study, the effect of drinking-water medication with florfenicol on Salmonellainfection in pigeons was examined. The pharmacokinetics of florfenicol in pigeons revealed a relatively high volume of distribution of 2.02 liters/kg of body weight and maximum concentrations in plasma higher than the MICs for the Salmonellastrain used (4 μg/ml) but quick clearance of florfenicol due to a short half-life of 1.73 h. Together with highly variable bioavailability and erratic drinking-water uptake, these parameters resulted in the inability to reach a steady-state concentration through the continuous administration of florfenicol in the drinking water. Florfenicol was capable of reducing only moderately the number of intracellular salmonellae in infected pigeon macrophages in vitro. Only at high extracellular concentrations (>16 μg/ml) was a more-than-10-fold reduction of the number of intracellular bacteria noticed. Florfenicol treatment of pigeons via the drinking water from 2 days after experimental inoculation with Salmonellaserovar Typhimurium until euthanasia at 16 days postinoculation resulted in a reduction of Salmonellashedding and an improvement in the fecal consistency. However, internal organs in florfenicol-treated pigeons were significantly more heavily colonized than those in untreated pigeons. In conclusion, the oral application of florfenicol for the treatment of pigeon paratyphoid contributes to the development of carrier animals through sub-MIC concentrations in plasma that do not inhibit intracellular persistency.

Three precisely defined deletion mutants of Salmonella enterica serovar Enteritidis were constructed, a guanine auxotrophic guaB mutant, a nonflagellated fliC mutant, and an auxotrophic and nonflagellated guaB fliC double mutant. All three mutants were less invasive than the wild-type strain in primary chicken cecal epithelial cells and the human epithelial cell line T84 and less efficiently internalized in the chicken macrophage cell line HD11. The fliC mutant was pathogenic in orally infected BALB/c mice, while the guaB mutant was attenuated and conferred protection against a challenge with the pathogenic parent strain. The guaB fliC double mutant was totally asymptomatic and conferred better protection than the guaB mutant. This indicates that the major flagellar protein flagellin is not required for efficient vaccination of BALB/c mice against Salmonella infection. The guaB fliC mutant was also safe for vaccination of 1-day-old chickens. After two immunizations, it induced statistically significant protection against infection of the internal organs of the birds by a virulent S. enterica serovar Enteritidis challenge strain but not against intestinal colonization. These data demonstrate that nonflagellated attenuated Salmonella mutants can be used as marker vaccines.

ABSTRACTThree precisely defined deletion mutants of Salmonella entericaserovar Enteritidis were constructed, a guanine auxotrophic ΔguaBmutant, a nonflagellated ΔfliCmutant, and an auxotrophic and nonflagellated ΔguaBΔfliCdouble mutant. All three mutants were less invasive than the wild-type strain in primary chicken cecal epithelial cells and the human epithelial cell line T84 and less efficiently internalized in the chicken macrophage cell line HD11. The ΔfliCmutant was pathogenic in orally infected BALB/c mice, while the ΔguaBmutant was attenuated and conferred protection against a challenge with the pathogenic parent strain. The ΔguaBΔfliCdouble mutant was totally asymptomatic and conferred better protection than the ΔguaBmutant. This indicates that the major flagellar protein flagellin is not required for efficient vaccination of BALB/c mice against Salmonellainfection. The ΔguaBΔfliCmutant was also safe for vaccination of 1-day-old chickens. After two immunizations, it induced statistically significant protection against infection of the internal organs of the birds by a virulent S. entericaserovar Enteritidis challenge strain but not against intestinal colonization. These data demonstrate that nonflagellated attenuated Salmonellamutants can be used as marker vaccines.