Relationship between the composition of vaginal bacterial populations and the reproductive stage in captive collared peccaries.

Abstract: The objective of the study was to i) characterize the aerobic and microaerophilic vaginal microbiota of collared peccaries (Pecari tajacu) across reproductive stages and ii) correlate microbiota findings with progesterone levels and vaginal cytology at each reproductive stage. Samples were collected for progesterone assessment (serum concentration), vaginal cytology, and microbial analysis (after isolation followed by MALDI-TOF identification) from four young pubescent, four non-pregnant, and three pregnant females. Microbial composition varied according to the reproductive stage: young pubescent females predominantly harbored Alcaligenes faecalis (Proteobacteria; 33.3%), non-pregnant females primarily hosted Bacillus badius and Staphylococcus microti (Firmicutes; 85.7%), and pregnant females had more Bacillus cereus and Mammaliicoccus sciuri (Firmicutes; 54.5%). No significant correlation (P > 0.05) was found between microbial proportions and progesterone levels or vaginal cytology. Although no differences were detected in the proportions of different vaginal bacterial populations, there was great qualitative diversity of species of microorganisms among females at different reproductive stages. While the small sample size may have limited our ability to detect more subtle quantitative differences, these findings provide foundational insights into the reproductive microbiota of collared peccaries, with potential implications for their conservation and management. Lay summary: Despite the importance of reproductive microbiomes in animal conservation, there is still a lack of knowledge in many wild species. The present study characterized for the first time the composition of the aerobic and microaerophilic microbiota (bacteria that can survive in the presence of oxygen or in low-oxygen conditions, respectively) of the vaginal tract from collared peccaries (pig-like mammals from Central and South America commonly known as musk hogs) at different reproductive stages. Although no differences were detected in the proportions of different vaginal bacterial populations, there was great qualitative diversity of species of microorganisms among females at different reproductive stages. These findings provide foundational insights into the reproductive microbiota of collared peccaries, with potential implications for their conservation and management.