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Microbiota of the gut, milk, and cowshed environment were examined at two dairy farms managed by automatic milking systems (AMS). Feed, rumen fluid, feces, milk, bedding, water, and airborne dust were collected and the microbiota on each was assessed by Illumina MiSeq sequencing. The most abundant taxa in feed, rumen fluid, feces, bedding, and water were Lactobacillaceae, Prevotellaceae, Ruminococcaceae, Ruminococcaceae, and Lactobacillaceae, respectively, at both farms. Aerococcaceae was the most abundant taxon in milk and airborne dust microbiota at farm 1, and Staphylococcaceae and Lactobacillaceae were the most abundant taxa in milk and airborne dust microbiota at farm 2. The three most prevalent taxa (Aerococcaceae, Staphylococcaceae, and Ruminococcaceae at farm 1 and Staphylococcaceae, Lactobacillaceae, and Ruminococcaceae at farm 2) were shared between milk and airborne dust microbiota. Indeed, SourceTracker indicated that milk microbiota was related with airborne dust microbiota. Meanwhile, hierarchical clustering and canonical analysis of principal coordinates demonstrated that the milk microbiota was associated with the bedding microbiota but clearly separated from feed, rumen fluid, feces, and water microbiota. Although our findings were derived from only two case studies, the importance of cowshed management for milk quality control and mastitis prevention was emphasized at farms managed by AMS., (© 2019 Japanese Society of Animal Science.)

The microbiota of whole crop corn silage and feces of silage-fed dairy cows were examined. A total of 18 dairy cow feces were collected from six farms in Japan and China, and high-throughput Illumina sequencing of the V4 hypervariable region of 16S rRNA genes was performed. Lactobacillaceae were dominant in all silages, followed by Acetobacteraceae, Bacillaceae, and Enterobacteriaceae. In feces, the predominant families were Ruminococcaceae, Bacteroidaceae, Clostridiaceae, Lachnospiraceae, Rikenellaceae, and Paraprevotellaceae. Therefore, Lactobacillaceae of corn silage appeared to be eliminated in the gastrointestinal tract. Although fecal microbiota composition was similar in most samples, relative abundances of several families, such as Ruminococcaceae, Christensenellaceae, Turicibacteraceae, and Succinivibrionaceae, varied between farms and countries. In addition to the geographical location, differences in feeding management between total mixed ration feeding and separate feeding appeared to be involved in the variations. Moreover, a cow-to-cow variation for concentrate-associated families was demonstrated at the same farm; two cows showed high abundance of Succinivibrionaceae and Prevotellaceae, whereas another had a high abundance of Porphyromonadaceae. There was a negative correlation between forage-associated Ruminococcaceae and concentrate-associated Succinivibrionaceae and Prevotellaceae in 18 feces samples. Succinivibrionaceae, Prevotellaceae, p-2534-18B5, and Spirochaetaceae were regarded as highly variable taxa in this study. These findings help to improve our understanding of variation and similarity of the fecal microbiota of dairy cows with regard to individuals, farms, and countries. Microbiota of naturally fermented corn silage had no influence on the fecal microbiota of dairy cows.

Although diet has an important influence on the composition of gut microbiota, the impact of dietary protein sources has only been studied to a minor extent. In this study, we examined the influence of different dietary protein sources regarding the effects of prebiotic oligosaccharides on the composition and metabolic activity of gut microbiota. Thirty female rats were fed casein and soy protein isolate with cellulose, raffinose (RAF), and fructooligosaccharides (FOS). Microbiota composition was examined by real-time qPCR and denaturing gradient gel electrophoresis. Dietary protein source affected cecum microbiota; acetic acid concentration and Lactobacillus spp. populations were greater with soy protein than with casein. Prebiotic oligosaccharides had distinctive effects on gut microbiota; RAF increased the acetic acid concentration and Bifidobacterium spp. populations, and FOS increased the butyric acid concentration regardless of the dietary protein. Likewise, Bifidobacterium sp., Collinsella sp., and Lactobacillus sp. were detected in microbiota of the rats fed RAF, and Bacteroides sp., Roseburia sp., and Blautia sp. were seen in microbiota of the rats fed FOS. Interactions between dietary proteins and prebiotic oligosaccharides were observed with Clostridium perfringens group populations and cecum IgA concentration. RAF and FOS decreased C. perfringens group populations in casein-fed rats, and the combination of soy protein and RAF substantially increased cecum IgA concentration. These results indicate that dietary proteins can differentially modulate the effects of prebiotic oligosaccharides on gut fermentation and microbiota, depending on the type of carbohydrate polymers involved., (© 2016 Institute of Food Technologists®)

A large amount of secretory immunoglobulin A (S-IgA) is secreted in the alimentary tract of mammals. It has been reported that S-IgA coats a portion of commensal intestinal bacteria in human and mouse. However, S-IgA-coated bacteria have not been studied in pigs and calves. In this study, we evaluated the distribution of S-IgA-coated commensal intestinal bacteria in each portion of the gastrointestinal tracts of pigs and calves. Immunoglobulin G (IgG)-coated bacteria were also analyzed because a considerable amount of IgG is secreted in the gastrointestinal tracts of pigs, and in particular, calves. S-IgA- or IgG-coated bacteria were detected in all the segments of the gastrointestinal tracts of pigs and calves. The proportion of S-IgA-coated bacteria to total bacteria (i.e. S-IgA coating ratio) varied in the segments of the gastrointestinal tract in pigs, whereas those of calves were nearly the same throughout the gastrointestinal tract. The S-IgA and IgG coating ratios were higher in pigs than in calves for all segments of the gastrointestinal tract., (© 2012 The Authors. Animal Science Journal © 2012 Japanese Society of Animal Science.)

Some commensal intestinal bacteria in humans and mice are coated with secretory immunoglobulin A (S-IgA). It has been suggested that the S-IgA coating of commensal bacteria does not occur at random and thus identification of S-IgA-coated bacterial genera/species should help in elucidating the interaction between S-IgA and commensal intestinal bacteria, but no method of identifying the genera/species of S-IgA-coated bacteria has been established. To identify S-IgA-coated bacterial composition, we developed a method combining immunohistochemical detection of S-IgA and subsequent 16S rRNA targeted fluorescence in situ hybridization (FISH) analysis. Human and mouse fecal S-IgA coated bacterial composition was evaluated by this newly developed method with 10 frequently-used FISH probes. Fecal S-IgA-coated bacterial composition was successfully analyzed by this method, and this suggests that Enterobacteriaceae is preferably coated with S-IgA, whereas Bacteroides/Prevotella and Lactobacillus/Enterococcus groups appear to be poorly coated with S-IgA.

It is reported that some, but not all, bacteria in human faeces are coated with secretory immunoglobulin A (S-IgA). We evaluated the proportion of S-IgA-coated bacteria to total intestinal bacteria (S-IgA coating ratio) in the gastrointestinal tract of two different strains of mice supplied by two different suppliers. The S-IgA coating ratio was significantly different in each gastrointestinal segment and between mouse suppliers. The amount of non-bacteria-bound IgA (free IgA) in each gastrointestinal segment indicated that this difference in the S-IgA coating ratio might not be due to the amount of secreted IgA. Furthermore, immunoblotting analysis revealed that only a small amount of IgA (<5% to free-IgA) was used for the coating. This indicates that, although sufficient S-IgA was secreted to coat the entire intestinal population of bacteria, only some part of the bacteria were coated with S-IgA. This study suggests that the amount of luminal S-IgA may not determine the S-IgA coating ratio, and that the amount of IgA coating intestinal commensal bacteria is very small.

The accumulation of lithium by microorganisms was examined. Among the 70 strains of the 63 species tested (20 bacteria, 18 actinomycetes, 18 fungi, and 14 yeasts), a high lithium accumulating ability was exhibited by strains of the bacteria, Arthrobacter nicotianae and Brevibacterium helovolum. Lithium accumulation by A. nicotianae cells was strongly affected by the pH of the solution. The amount of accumulated lithium was maximum at pH 6. Cells immobilized with polyacrylamide gel also adsorbed lithium. They could be reused during repeated adsorptions, and adsorbed 548 micromol of lithium/g dry wt. cells. The adsorbed lithium was quantitatively and easily desorbed with 1 M hydrochloric acid using a column system.