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Toulouse, France

Bertin Y.,French National Institute for Agricultural Research | Chaucheyras-Durand F.,Lallemand Animal Nutrition | Robbe-Masselot C.,Lille University of Science and Technology | Durand A.,French National Institute for Agricultural Research | And 6 more authors.
Environmental Microbiology | Year: 2013

The bovine gastrointestinal (GI) tract is the main reservoir for enterohaemorrhagic Escherichia coli (EHEC) responsible for food-borne infections. Characterization of nutrients preferentially used by EHEC in the bovine intestine would help to develop ecological strategies to reduce EHEC carriage. However, the carbon sources that support the growth of EHEC in the bovine intestine are poorly documented. In this study, a very low concentration of glucose, the most abundant monomer included in the cattle dietary polysaccharides, was detected in bovine small intestine contents (BSIC) collected from healthy cows at the slaughterhouse. Six carbohydrates reported to be included in the mucus layer covering the enterocytes [galactose, N-acetyl-glucosamine (GlcNAc), N-acetyl- galactosamine (GalNAc), fucose, mannose and N-acetyl neuraminic acid (Neu5Ac)] have been quantified for the first time in BSIC and accounted for a total concentration of 4.2mM carbohydrates. The genes required for enzymatic degradation of the six mucus-derived carbohydrates are highly expressed during the exponential growth of the EHEC strain O157:H7 EDL933 in BSIC and are more strongly induced in EHEC than in bovine commensal E.coli. In addition, EDL933 consumed the free monosaccharides present in the BSIC more rapidly than the resident microbiota and commensal E.coli, indicating a competitive ability of EHEC to catabolize mucus-derived carbohydrates in the bovine gut. Mutations of EDL933 genes required for the catabolism of each of these sugars have been constructed, and growth competitions of the mutants with the wild-type strain clearly demonstrated that mannose, GlcNAc, Neu5Ac and galactose catabolism confers a high competitive growth advantage to EHEC in BSIC and probably represents an ecological niche for EHEC strains in the bovine small intestine. The utilization of these mucus-derived monosaccharides by EDL933 is apparently required for rapid growth of EHEC in BSIC, and for maintaining a competitive growth rate as compared with that of commensal E.coli. The results suggest a strategy for O157:H7 E.coli survival in the bovine intestine, whereby EHEC rapidly consumes mucus-derived carbohydrates that are poorly consumed by bacteria belonging to the resident intestinal microbiota, including commensal E.coli. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

Standen B.T.,University of Plymouth | Rawling M.D.,University of Plymouth | Davies S.J.,University of Plymouth | Castex M.,Lallemand Animal Nutrition | And 4 more authors.
Fish and Shellfish Immunology | Year: 2013

The application of probiotics in aquaculture has received concerted research efforts but the localised intestinal immunological response of fish to probiotic bacteria is poorly understood. Therefore, a study was conducted to evaluate the probiotic effect of Pediococcus acidilactici on Nile tilapia (Oreochromis niloticus) with specific emphasis on intestinal health and probiotic levels as well as system level responses such as growth performance, feed utilization and haemato-immunological parameters under non-challenged conditions. Fish (9.19±0.04g) were fed either a control diet or a P.acidilactici supplemented diet (at 2.81×106CFUg-1) for six weeks. At the end of the study the probiotic was observed to populate the intestine, accounting for ca. 3% (1.59×105CFUg-1) of the cultivable intestinal bacterial load. Real-time PCR indicated that the probiotic treatment may potentiate the immune-responsiveness of the intestine as up-regulation of the gene expression of the pro-inflammatory cytokine TNFα was observed in the probiotic fed fish (P<0.05). Light microscopy observations revealed elevated intraepithelial leucocyte (IEL) levels in the intestine of P.acidilactici fed tilapia after six weeks (P<0.05) of feeding and a trend towards elevated goblet cells was also observed after six weeks feeding (P=0.08). Concomitantly at week six, along with elevated IELs and elevated TNFα mRNA levels in the intestine, an increased abundance of circulating neutrophils and monocytes were observed in fish fed the probiotic supplemented diet (P<0.05). This haemopoietic expansion of innate immune cells could be reflective of an elevated state of immuno-readiness. Together these results suggest that the probiotic has a protective action on the intestinal mucosal cells, stimulating the innate immune response after feeding for a period of six weeks. These immunological modulations did not impair growth performance or the remaining haematological and zootechnical parameters compared to the control group (P>0.05). © 2013 Elsevier Ltd.

DeVries T.J.,University of Guelph | Chevaux E.,Lallemand Animal Nutrition
Journal of Dairy Science | Year: 2014

The objective of this study was to determine if the feeding behavior of dairy cows is modified through live yeast supplementation. Twelve lactating Holstein dairy cows (2 primiparous and 10 multiparous) were individually exposed, in a replicated crossover design, to each of 2 treatment diets (over 35-d periods): (1) a control TMR and (2) a control TMR plus 1 × 1010 cfu/head per day of live yeast (Saccharomyces cerevisiae CNCM I-1077; Levucell SC20; Lallemand Animal Nutrition, Montreal, QC, Canada). Milk production, feeding, and rumination behavior were electronically monitored for each animal for the last 7 d of each treatment period. Milk samples were collected for the last 6 d of each period for milk component analysis. Dry matter intake (28.3kg/d), eating time (229.3min/d), and rate (0.14kg of dry matter/min) were similar between treatments. With yeast supplementation, meal criteria (minimum intermeal interval) were shorter (20.0 vs. 25.8min), translating to cows tending to have more meals (9.0 vs. 7.8 meals/d), which tended to be smaller in size (3.4 vs. 3.8kg/meal). Yeast-supplemented cows also tended to ruminate longer (570.3 vs. 544.9min/d). Milk yield (45.8kg/d) and efficiency of production (1.64kg of milk/kg of dry matter intake) were similar between treatments. A tendency for higher milk fat percent (3.71 vs. 3.55%) and yield (1.70 vs. 1.63kg/d) was observed when cows were supplemented with yeast. No differences in milk fatty acid composition were observed, with the exception of a tendency for a greater concentration of 18:2 cis-9,cis-12 fatty acid (2.71 vs. 2.48% of total fatty acids) with yeast supplementation. Yeast-supplemented cows had lower mean ruminal temperature (38.4 vs. 38.5°C) and spent less time with rumen temperature above 39.0°C (353.1 vs. 366.9min/d), potentially indicating improved rumen pH conditions. Overall, the results show that live yeast supplementation tended to improve meal patterns and rumination, rumen temperature, and milk fat production. © 2014 American Dairy Science Association.

Chaucheyras-Durand F.,Lallemand Animal Nutrition | Chaucheyras-Durand F.,French National Institute for Agricultural Research | Ossa F.,National Research Council Canada
Professional Animal Scientist | Year: 2014

Ruminants are able to degrade and use fibrous feed as a source of energy and nutrients because of the presence of complex anaerobic microbiota in the rumen, composed mainly of bacteria, fungi, and ciliate protozoa. Ruminal microorganisms play different roles in feed digestion and act synergistically to ferment plant structural and nonstructural carbohydrates and proteins. This review reports the latest assessment of microbiota diversity in the rumen ecosystem and summarizes the molecular techniques and the newly available "omic" technologies, based on DNA and RNA sequence analysis, which allow for new insights into the structure and functions of these complex microbial communities. © 2014 American Registry of Professional Animal Scientists.

Merrifield D.L.,Scottish Association for Marine Science | Dimitroglou A.,Scottish Association for Marine Science | Foey A.,University of Plymouth | Davies S.J.,Scottish Association for Marine Science | And 2 more authors.
Aquaculture | Year: 2010

Salmonids are an important contributor to fish production in many countries. Concerted research efforts have concentrated on optimising production with eco-friendly alternatives to the therapeutic use of antimicrobials. Probiotics and prebiotics offer potential alternatives by providing benefits to the host primarily via the direct or indirect modulation of the gut microbiota. Suggested modes of action resulting from increased favourable bacteria (e.g. lactic acid bacteria and certain Bacillus spp.) in the gastrointestinal (GI) tract include the production of inhibitory compounds, competition with potential pathogens, inhibition of virulence gene expression, enhancing the immune response, improved gastric morphology and aiding digestive function. The application of probiotics and prebiotics may therefore result in elevated health status, improved disease resistance, growth performance, body composition, reduced malformations and improved gut morphology and microbial balance. Current research demonstrates successful proof of these concepts and a foundation for applications in salmonid aquaculture. However, application strategies applied in current studies are varied and often impractical at industrial level farming; thus, it is difficult to plan an effective feeding strategy for commercial level applications. Future studies should focus on providing practical industrial scale applications. Additionally, from a scientific perspective we must have a better understanding of the mucosal-bacterial interactions which mediate the host benefits in order to achieve optimal utilisation. © 2010 Elsevier B.V. All rights reserved.

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