Age-Related Specificities of the Gut Microbiota Composition of Rhesus Macaques Kept in Captivity

The strategy of correcting the composition of the intestinal microbiota shows significant promise for the treatment of gastrointestinal diseases. There is a confirmed link between the state of the colonic microbiota and human pathologies. Monkeys-in particular, rhesus macaques-are recognized as the best animal model to study the mechanisms controlling the development of both acute and chronic inflammation. The similarity of key anatomical and physiological systems between macaques and humans provides significant advantages for conducting biomedical research aimed at evaluating the safety and efficacy of microbial drugs designed to normalize intestinal microbiocenoses using these animals. The aim of the study was to analyze the taxonomic composition of the intestinal microbiota of rhesus macaques of different ages kept in captivity. Seventeen fecal samples collected from clinically healthy rhesus macaques kept in captivity were included in the study. DNA was isolated from fecal samples using a MagMAX Microbiome Ultra Nucleic Acid Isolation Kit. Samples were analyzed by metagenomic sequencing of the V3-V4 region of the 16S rRNA gene. Analysis of the 16S rRNA metagenomic sequencing data showed that the intestinal microbiota of rhesus macaques is dominated by the bacteria belonging to the Firmicutes, Bacteriodetes, and Actinobacteriota phyla, which are also predominant in humans, and that the ratio between them varies in different age groups. A decrease in Actinobacteriota abundance and Firmicutes/Bacteriodetes ratio was observed with age. The alpha diversity of gut microbiota was not statistically different between different age groups of rhesus macaques, while the highest absolute values of alpha diversity were observed in the group of young individuals. The analysis of differential abundance showed that the gut microbiota of young individuals was enriched with butyrate-producing bacteria, indicating that the local intestinal immunity was not disturbed. Older individuals showed an increased content of Streptococcus and Lachnospiraceae, which may be interpreted as a marker of inflammation reflecting the age-related specificities of the monkey gut microbiota. The gut microbiota of rhesus macaques varies between age groups, with less variation being observed within the groups of babies and young individuals than in the group of old individuals. The results of sequencing monkey intestinal microbiota demonstrated the similarity of its composition to the human intestinal microbiota, the specificities of the age-related changes in the taxonomic composition of the intestinal microbiota of rhesus macaques, which to certain extent allows the use of rhesus macaques as a model to study the age dynamics of human intestinal microbiota, which is promising for age-related studies of various substances, compositions and other factors affecting human body potentially capable of exerting positive or negative effects on the human microbiota.