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Endometritis has a major impact on fertility in postpartum dairy cows. Since previous studies showed an association between reproductive microbiota and perinatal disease, we monitored both bovine uterine and vaginal microbiota in primiparous cows to elucidate the effect of early postpartum microbiota on endometritis. Uterine and vaginal samples were collected at time points from pre-calving to 35 days postpartum (DPP), and analyzed by 16S rRNA sequencing, combined with ancillary bacterial culture. A total of seven healthy cows and seven cows diagnosed with endometritis on 35 DPP were used in the current study. The uterine and vaginal microbiota showed a maximum of 20.1% shared amplicon sequence variants (ASVs) at linked time points. 16S rRNA based analysis and traditional culture methods revealed that Trueperella showed a higher abundance in both uterus and vagina of the endometritis group compared to the healthy group on 21 DPP (U-test p < 0.05). Differential abundance analysis of the uterine microbiota showed that Enterococcus and six bacterial genera including Bifidobacterium were unique to the healthy group on the day of calving (0 DPP) and 28 DPP, respectively. In contrast, Histophilus and Mogibacteriaceae were characteristic bacteria in the vagina pre-calving in cows that later developed endometritis, suggesting that these bacteria could be valuable to predict clinical outcomes. Comparing the abundances of bacterial genera in the uterine microbiota, a negative correlation was observed between Trueperella and several bacteria including Lactobacillus. These results suggest that building an environment where there is an increase in bacteria that are generally recognized as beneficial, such as Lactobacillus, may be one possible solution to reduce the abundance of Trueperella and control endometritis.

Background Clostridium butyricum MIYAIRI 588 (CBM 588) is a probiotic bacterium that is used as an anti-diarrheal medicine in Japan. However, the impact of this probiotic on the gut microbiome has not been fully elucidated, especially, when used with antimicrobials. Material and methods In an in vivo study, CBM 588 monotherapy, clindamycin monotherapy, CBM 588 and clindamycin (combination therapy), or normal saline (control) was orally administered to mice for 4 days, and fecal samples were collected for 18 days to enumerate C. butyricum. We also extracted DNA from these fecal samples for metagenomics analysis by amplification of the V3-V4 region of the bacterial 16S rRNA gene and MiSeq Illumina sequencing. In addition, the concentrations of some short chain fatty acids were assessed in the fecal samples. A histological analysis was also conducted. Results On day 4 (the last treatment day), there was no difference in the total counts of C. butyricum between the CBM 588 monotherapy and combination therapy groups (5.21 ± 0.78 vs. 5.13 ± 0.45 log10 cfu/g, p = 0.86). Clindamycin treatment resulted in dramatic increases in the phylum Firmicutes, especially Enterobacteriaceae, Clostridiaceae, Lactobacillus, and Enterococcus, compared with the other groups during the treatment period. CBM 588 treatment modified the bacterial community composition at lower phylogenetic levels. Some bacterial taxa, such as Bifidobacterium, Coprococcus, and Bacteroides, were significantly increased in the combination therapy group when compared with the other groups. In the metabolic analysis, CBM 588 enhanced lactic acid production. It also enhanced the efficiency of lactic acid use for the production of butyric acid. Only the clindamycin monotherapy group showed abnormal colon tissue, with superficial epithelial necrosis and the presence of inflammatory cells. Conclusion CBM 588 treatment modulated the gut microbiota composition under dysbiosis due to the use of an antimicrobial with strong activity against anaerobes and significantly reduced epithelial damage.

Flavophospholipol (FPL) is an antimicrobial feed additive that has been approved for use in livestock animals and has the potential to decrease horizontal dissemination of antimicrobial resistance genes. Since previous studies showed that FPL has an inhibitory effect on plasmid transfer, in vitro experiments have proven the efficacy of FPL in reducing the conjugative transfer of plasmids encoding the extended-spectrum β-lactamase (ESBL) and vanA genes. These are among the most important antimicrobial resistance loci known. ESBL-producing Escherichia coli and vancomycin-resistant Enterococcus faecalis (VRE) were exposed to several concentrations of FPL, and transfer frequency and plasmid curing activity were determined. FPL inhibited the conjugative transfer of plasmids harboring ESBL and vanA genes in a concentration-dependent manner in all strains. Further transfer experiments revealed that FPL could decrease or increase transfer frequency depending on plasmid type when transfer frequency was at low levels. The plasmid curing activity of FPL was also observed in ESBL-producing E. coli in a concentration-dependent manner, suggesting that they partially contribute to the inhibition of conjugative transfer. These results suggest that the use of FPL as a feed additive might decrease the dissemination of ESBL and vanA genes among livestock animals.

Clostridium butyricum MIYAIRI 588 (CBM 588) is a nonpathogenic, anaerobic, gram-positive bacillus characterized by the production of short-chain fatty acids, including butyrate. The safety and tolerance of CBM 588 was investigated as a feed additive for broiler chickens, weaned piglets, and turkeys. CBM 588 administered to broilers at doses up to 5 × 107 CFU/g feed for 42 days produced no detrimental effects on zootechnical performance, natural mortality, hematology, or biochemical parameters. Piglets receiving CBM 588 at doses up to 5 × 107 CFU/g feed for 42 days showed no significant differences from controls in zootechnical performance, mortality, or morbidity. Finally, CBM 588 administered to turkeys at doses up to 2.5 × 107 CFU/g feed for 84 days produced no detrimental effects on zootechnical performance, hematology, or biochemical parameters. Some improvements in zootechnical performance were seen with CBM 588, including improved average daily gain (ADG) and feed conversion for broilers from days 1 to 21 as well as final body weight and overall ADG for turkeys. Overall, CBM 588 administered in feed at dose up to 5 × 107 CFU/g (broilers and piglets) or 2.5 × 107 CFU/g (turkeys) was shown to be safe and well-tolerated in all tested animals and may provide some nutritional benefit when added to standard commercial feed info:eu-repo/semantics/publishedVersion