Project description:Campylobacter jejuni is the major cause of acute gastroenteritis in the developed world. It is usually acquired through contaminated poultry as C. jejuni causes a silent asymptomatic infection of the chicken. Pathogens face different sources of stress during its transit through the gut. In this study, we describe the ability of C. jejuni to survive nitrosative stress at very low oxygen levels that reflect those in hypoxic gut environments. Specifically, we here explore an innovative model of signal recognition during colonization. We use a diffusion capsule to feed small, diffusible molecules from chicken caecal matter into a microaerobic C. jejuni culture to study the transcriptomic changes mounted as response to chemical signals present in the chicken gut. We find that in early stages of exposure to the caecal contents (10 min) the dual component colonization regulator, dccR, plays an important yet not fully understood role. Although the caecal material contains cyanide derived from plant sources, we find no role for a truncated globin (encoded by ctb), which has previously been implicated in resistance to this haem ligand.
Project description:One of the major transmission routes for the foodborne bacterial pathogen Campylobacter is undercooked poultry meat, contaminated from intestinal contents during processing. In broilers, Campylobacter can grow to very high densities in the caeca, and is often considered to be a commensal or an opportunistic pathogen in poultry. Reduction of caecal loads of Campylobacter may assist in lowering incidence rates of Campylobacter food poisoning. To achieve this, there needs to be a better understanding of the dynamics of Campylobacter colonization in its natural niche, and the effect of the local microbiome on colonization. Previous studies have shown that the microbiome differed between Campylobacter colonized and non-colonized chicken intestinal samples. To characterize the microbiome of Campylobacter-colonized broilers, caecal samples of 100 randomly selected birds from four farms were analyzed using amplified 16S rRNA gene sequences. Bacterial taxonomic analysis indicated that inter-farm variation was greater than intra-farm variation. The two most common bacterial groups were Bacteroidetes and Firmicutes which were present in all samples and constituted 29.7-63.5 and 30.2-59.8% of the bacteria present, respectively. Campylobacter was cultured from all samples, ranging from 2 to 9 log10 CFU g-1. There was no clear link between Campylobacter counts and Firmicutes, Bacteroidetes, or Tenericutes levels in the 16S rRNA operational taxonomic unit (OTU)-based analysis of the caecal microbiome, but samples with high Campylobacter counts (>9 log CFU g-1) contained increased levels of Enterobacteriaceae. A decrease in Lactobacillus abundance in chicken caeca was also associated with high Campylobacter loads. The reported associations with Lactobacillus and Enterobacteriaceae match changes in the intestinal microbiome of chickens and mice previously reported for Campylobacter infection, and raises the question about temporality and causation; as to whether increases in Campylobacter loads create conditions adverse to Lactobacilli and/or beneficial to Enterobacteriaceae, or that changes in Lactobacilli and Enterobacteriaceae levels created conditions beneficial for Campylobacter colonization. If these changes can be controlled, this may open opportunities for modulation of chicken microbiota to reduce Campylobacter levels for improved food safety.
Project description:16S rRNA amplicon sequencing characterization of caecal microbiome composition of broilers and free-range slow-growing chickens throughout their productive lifespan
Project description:RNA was extracted from the meninges of mice from either Specific pathogen free or Germ free facilities or from the offspring of mice reconstituted with different human microbiomes.
Project description:HuMiChip2 was applied to analyze perform both strain-level identification and the functional profiling of human gut microbiomes from alcoholic cirrhosis patients and healthy individuals with alcohol abuse.
Project description:Despite the existence of a number of studies investigating the effect of insect meal on the growth performance of broilers, knowledge about the metabolic effects of insect meal in broilers is still scarce. Thus, the present study investigated the effect of partial replacement of soybean meal with Hermetia illucens (HI) larvae meal on the liver transcriptome, the plasma metabolome and the cecal microbiome in broilers. For the study, 72 male one-day-old Cobb 500 broilers were divided into three groups (n = 12) and fed three different diets with either 0% (HI0), 7.5% (HI7.5) or 15% (HI15) defatted HI meal for 35 d. While body weight (BW) gain, feed intake, and feed:gain ratio did not differ between groups, breast muscle weight, carcass yield and apparent ileal digestibility (AID) of 12 amino acids were higher in group HI15 than in group HI0 (P > 0.05). Indicators of α-diversity (Chao1 and Observed) in the cecal digesta were higher in groups HI15 and HI7.5 than in group HI0 (P < 0.05). The abundance of 5 families and 18 genera, all of which belonged to the Firmicutes phylum, in the cecal digesta differed among groups (P < 0.05). Concentrations of butyric acid, valeric acid and isobutyric acid in the cecal digesta were lower in group HI15 than in the other two groups (P > 0.05), whereas those of total and other short-chain fatty acids were not different between groups. Liver transcriptomics revealed a total of 70 and 61 differentially expressed transcripts between groups HI15 vs. HI0 and between groups HI7.5 vs HI0, respectively, (P > 0.05). Targeted metabolomics identified 138 metabolites, most of which were triglyceride species, being different between the three groups (FDR < 0.05). According to this study, dietary inclusion of HI larvae meal has no detrimental impact but increases breast muscle weight and carcass weight in broilers suggesting that HI larvae meal can be recommended as a sustainable alternative protein source for broilers.
Project description:To investigate genes involved in abdominal fat deposition and fat metabolism of broilers with dw gene, we used highthroughput sequencing to detect the differentially expressed genes in livers and abdominal fats of dwarf broilers which were fed with a normal diet and a high-fat diet, respectively. The broilers began to fed with a normal or a high-fat diet in 1-week-old. After 7 weeks, the broilers were be executed and the livers and abdominal fats were used to extracted total RNAs. Finally, the total RNAs were be sequenced used BGISEQ-500 platform.
Project description:RNA from in vitro grown Salmonella typhimurium is compared with RNA extracted from Salmonella typhimurium from infected chick caecums using a common DNA reference. Keywords: Disease state analysis, infected versus uninfected, common reference Five replicates from infected chick caecal contents compared to a common reference. Three replicates from in vitro grown Salmonella compared to a common reference. The common reference was genomic DNA and always occupies the Cy3 channel (channel 2).