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The methanogenic archaea found in the ceca of leghorn chicken were quantitatively studied for phylogeny based on the 16S rRNA gene studies. Methanobrevibacter woesei is the major species found in the chicken ceca.

Changes in the microenvironment of a crop caused by feed deprivation are significant regulators of the survival of Salmonella enteritidis and influence the susceptibility of molted hens to S enteritidis infections. This was gleaned from a study of the physiological changes in the crop associated with molt induced by feed withdrawal. Results showed that feed withdrawal alters the microenvironment of the crop by causing substantial reductions in the Lactobacillus population and in lactate and total volatile fatty acid concentrations and an increase in pH. Such changes of the crop environment were found to be accompanied by increased S enteritidis colonization of the crop and cecum with invasion of the spleen and liver.

Characterization of a tungsten-tolerant mutant (CA6) of the diazotroph Azotobacter vinelandii based on the results of growth experiments showed that CA6 requires nitrogenases 1 and 3 for growth in nitrogen (N)-free medium containing Na2MoO4. The wild-type strain CA repressed the transcription of the anfHDGK gene cluster, which encode the nitrogenase enzymes. This suggests that expression of nitrogenases is dependent on the presence of molybdenum.

Glass impingers used to detect the presence of sludge-derived airborne bacteria and pathogen indicators show that sludge application sites contain no airborne Clostridium spp., somatic coliphages, fecal coliforms, or fecal streptococci. The concentration of airborne heterotrophic bacteria is 10 to the fifth power CFU/cu m. Hydrogen sulfide producers and pathogenic clostridia occur on the sites where there is physical agitation of the sludge material. A 16S-23S interspacer region used in PCR-based ribotyping shows that the airborne and the sludge bacteria are genetically distinct.

Humans and animals encounter a summation of exposures during their lifetime (the exposome). In recent years, the scope of the exposome has begun to include microplastics. Microplastics (MPs) have increasingly been found in locations, including in animal gastrointestinal tracts, where there could be an interaction with Salmonella enterica serovar Typhimurium, one of the commonly isolated serovars from processed chicken. However, there is limited knowledge on how gut microbiomes are affected by microplastics and if an effect would be exacerbated by the presence of a pathogen. In this study, we aimed to determine if acute exposure to microplastics in vitro altered the gut microbiome membership and activity. The microbiota response to a 24 h co-exposure to Salmonella enterica serovar Typhimurium and/or low-density polyethylene (PE) microplastics in an in vitro broiler cecal model was determined using 16S rRNA amplicon sequencing (Illumina) and untargeted metabolomics. Community sequencing results indicated that PE fiber with and without S. Typhimurium yielded a lower Firmicutes/Bacteroides ratio compared with other treatment groups, which is associated with poor gut health, and overall had greater changes to the cecal microbial community composition. However, changes in the total metabolome were primarily driven by the presence of S. Typhimurium. Additionally, the co-exposure to PE fiber and S. Typhimurium caused greater cecal microbial community and metabolome changes than either exposure alone. Our results indicate that polymer shape is an important factor in effects resulting from exposure. It also demonstrates that microplastic-pathogen interactions cause metabolic alterations to the chicken cecal microbiome in an in vitro chicken cecal mesocosm. [ABSTRACT FROM AUTHOR]