A rugged life: how host-microbiome adaptations associated with the semi-feral lifestyle of gayal (Bos frontalis)

The semi-domesticated gayal ( Bos frontalis ) is an endangered browsing ruminant inhabiting the rugged Eastern Himalayan foothills, and maintains an energy-intensive lifestyle on nutrient-poor, fiber-rich feed. However, the dietary, microbial, and host physiological features underlying this adaptation remain poorly understood. Here, we analyzed fecal metagenomes from ten bovine populations ( n = 334) to characterize dietary composition. Then we profiled the four-chambered (FC) stomach microbiome in adult gayal ( Bos frontalis ), yak ( Bos grunniens ), and taurine cattle ( Bos taurus ). Host transcriptomes were profiled across the FC stomach in adult individuals from gayal, yak and cattle. Dietary analysis revealed a woody plant-dominated, bamboo-rich dietary pattern in gayal. Gastric metagenomes in gayal showed high population-level microbial diversity, pronounced individual-associated community structure, and functional potentials related to aromatic compound transformation, nitrogen metabolism, and metabolic flexibility. Transcriptomes revealed compartment-specific specialization in the gayal stomach, including rumen immune signatures and reticulum contractile/electrophysiological features. Exploratory compartment-level integration further suggested possible consistency between host transcriptomic features and microbial functional potential. Together, these multi-omics findings suggest a host-microbiome system potentially associated with the utilization of chemically complex, low-quality forage, providing a framework for understanding digestive features of browsing ruminants and for conserving host-associated gastrointestinal microbiomes.