Cecal metabolome of gnotobiotic (containing a 14-member synthetic human gut microbiota), and germ-free mice fed with two distinct rodent diets with varying fiber content.
Project description:The amount and nature of dietary starch are known to influence the extent and site of feed digestion in ruminants. However, how starch degradability may affect methanogenesis and methanogens along the ruminant's digestive tract is poorly understood. This study examined the diversity and metabolic activity of methanogens in the rumen and cecum of lambs receiving wheat or corn high-grain-content diets. Methane production in vivo and ex situ was also monitored. In vivo daily methane emissions (CH(4) g/day) were 36% (P < 0.05) lower in corn-fed lambs than in wheat-fed lambs. Ex situ methane production (μmol/h) was 4-fold higher for ruminal contents than for cecal contents (P < 0.01), while methanogens were 10-fold higher in the rumen than in the cecum (mcrA copy numbers; P < 0.01). Clone library analysis indicated that Methanobrevibacter was the dominant genus in both sites. Diet induced changes at the species level, as the Methanobrevibacter millerae-M. gottschalkii-M. smithii clade represented 78% of the sequences from the rumen of wheat-fed lambs and just about 52% of the sequences from the rumen of the corn-fed lambs. Diet did not affect mcrA expression in the rumen. In the cecum, however, expression was 4-fold and 2-fold lower than in the rumen for wheat- and corn-fed lambs, respectively. Though we had no direct evidence for compensation of reduced rumen methane production with higher cecum methanogenesis, the ecology of methanogens in the cecum should be better considered.
Project description:Growing broiler chickens of the Cobb500 strain were used to determine the effects on intestinal microbiota composition of a protein-free (PF) diet as compared to a diet based in casein (CAS) as the only protein source. CAS was formulated to contain the same amount of protein (190 g kg-1) as a commercial Maize-soy diet which was used as a practical reference. The ileal AA flow (g kg-1 dry matter intake) was significantly higher (P < 0.001) than PF in birds fed protein containing diets (CAS or Maize-soy). Taken as a whole (discriminant and ANOSIM analysis), the intestinal (ileal and caecal contents and ileal tissue) microbiota composition of PF and CAS were significantly (P < 0.001) different from Maize-soy and not different from each other in some cases. RT-qPCR and sequencing analysis of the ileal and caecal microbiota revealed significant (P < 0.05) differences in a number of bacterial groups between broilers fed PF, CAS or Maize-soy diets. The main result was that the lack of protein in the intestinal medium of PF birds resulted in a drop of Lactobacillus spp. counts (on average, 43 in PF vs 1,734 in the Maize-soy diet) and increased Enterobacteriaceae (on average, 419 in PF vs 172 in the Maize-soy diet) and other potentially pathogenic bacterial groups (in both intestinal contents and tissue). Thus, the lack of protein in the intestinal medium of PF birds resulted in a microbiota composition compatible with a pro-inflammatory state, and this effect was somewhat less marked in birds fed CAS. The results reported here suggest that the adverse effects on microbiota composition in broilers fed CAS were less marked than in those fed PF, which would be in line with a preferential use of a highly digestible protein containing diet to determine endogenous AA excretion instead of a PF diet.
Project description:To determine the impact of quercetin on honeybee development and physiology, we conducted an RNASeq analysis of gene expression in neonate larvae exposed for three days to control “bee candy” diet (comprising sucrose and sugar syrup) or diets to which 0.1 mM or 0.25 mM quercetin was added.
Project description:Female Crlj:CD1(ICR) mice were fed diets containing 0 (control), 5000 and 10000 ppm permethrin and 2500 ppm isoniazid (positive control for tumor induction) for periods of 7 and 14 days. We used microarrays to evaluate gene expression profiling in mouse lung at the early phase of treatment with permethrin and isoniazid.
Project description:Fermentation differs between the proximal and distal gut but little is known regarding how the bacterial communities differ or how they are influenced by diet. In order to investigate this, we compared community diversity in the cecum and feces of rats by 16S rRNA gene content and DNA shot gun metagenomics after feeding purified diets containing different fermentable substrates. Gut community composition was dependent on the source of fermentable substrate included in the diet. Cecal communities were dominated by Firmicutes, and contained a higher abundance of Lachnospiraceae compared to feces. In feces, community structure was shifted by varying degrees depending on diet towards the Bacteroidetes, although this change was not always evident from 16S rRNA gene data. Multi-dimensional scaling analysis (PCoA) comparing cecal and fecal metagenomes grouped by location within the gut rather than by diet, suggesting that factors in addition to substrate were important for community change in the distal gut. Differentially abundant genes in each environment supported this shift away from the Firmicutes in the cecum (e.g., motility) towards the Bacteroidetes in feces (e.g., Bacteroidales transposons). We suggest that this phylum level change reflects a shift to ammonia as the primary source of nitrogen used to support continued microbial growth in the distal gut.
Project description:This study was designed to evaluate the effects of dietary coated sodium butyrate (CSB) on the intestinal antioxidant, immune function, and cecal microbiota of laying hens. A total of 720 52-week-old Huafeng laying hens were randomly allocated into five groups and fed a basal diet supplemented with CSB at levels of 0 (control), 250 (S250), 500 (S500), 750 (S750), and 1000 (S1000) mg/kg for eight weeks. The results revealed that CSB supplementation quadratically decreased the malondialdehyde content and increased the superoxide dismutase activity of the jejunum as well as the total antioxidative capacity activity of the ileum (p < 0.05). Dietary CSB supplementation linearly decreased the diamine oxidase and D-lactic acid content of the serum (p < 0.05). Compared with the control group, the addition of CSB resulted in linear and/or quadratic effects on the mRNA expression of inflammatory cytokines TNF-α, IL-6, and IL-10 in the jejunum and ileum (p < 0.05). The short-chain fatty acid concentrations increased quadratically as supplemental CSB improved (p < 0.05). Additionally, dietary CSB levels had no effect on microbial richness estimators, but ameliorated cecal microbiota by raising the abundance of probiotics and lowering pathogenic bacteria enrichment. In conclusion, our results suggest that dietary supplementation with CSB could improve the intestinal health of laying hens via positively influencing the antioxidant capacity, inflammatory cytokines, short-chain fatty acids, and gut microbiota. In this study, 500 mg/kg CSB is the optimal supplement concentration in the hens’ diet.