Anthropogenic factors shape the gut microbiota of tigers in Indian tiger reserves

Tigers still face threats because of anthropogenic activities, including wildlife tourism and cattle grazing in tiger reserves. Previous studies have shown that human-related activities can impact gut health in other mammals. Many extrinsic factors shape gut bacteria and play a significant role in host health. However, very little is known about tiger gut bacteria and how they vary among different tiger reserves in India. To understand this, we collected fresh scats of tigers from five tiger reserves for two years from the buffer and core zones during all seasons (summer, monsoon, and winter). We investigated the gut bacterial composition using amplicon-based metabarcoding of the V4 region of the 16S rRNA gene. We also predicted KEGG orthologues and annotated the functional pathways to understand the role of gut bacteria in host health. Our study revealed that tiger gut bacterial community structures varied due to habitats and seasons. We identified thirty-six core bacterial genera (more than 90 % of samples) from all the samples. The microbiome abundance varied across tiger reserves. A few unique bacterial genera were also identified in some tiger reserves. We conclude that human-related activities in tiger reserves can influence the bacterial community structures, with potential implications for tiger health and fitness