Mucosal immune responses and intestinal microbiome associations in wild spotted hyenas (Crocuta crocuta)

Area of Science:

• Microbiome Research
• Immunology
• Wildlife Ecology

Background:

• Host-gut microbiome interactions are crucial at the intestinal mucosa, yet poorly understood in natural populations.
• Investigating these interactions requires controlling for host, social, and ecological variables in wild animals.

Purpose of the Study:

• To explore associations between the intestinal microbiome and mucosal immune measures in wild spotted hyenas.
• To identify specific microbial taxa and host factors influencing these gut-immune relationships.

Main Methods:

• Collected 199 samples from 158 wild spotted hyenas (Crocuta crocuta) in Serengeti National Park, Tanzania.
• Utilized multi-amplicon sequencing to profile microbiome composition.
• Measured fecal immunoglobulin A (IgA) and mucin levels.
• Employed probabilistic and machine learning models to analyze data.

Main Results:

• Immune measures (IgA, mucin) predicted microbiome similarity in an age-dependent manner.
• Associations were strongest with bacteria, intermediate with parasites, and weakest with fungi.
• Machine learning accurately predicted immune measures and identified key taxa, including symbiotic bacteria, unclassified bacteria, hookworms, and fungi.

Conclusions:

• Host immune factors significantly shape the gut microbiome composition in wild spotted hyenas.
• Age is a critical factor modulating the host-gut-immune axis in this species.
• Findings provide insights into the co-evolutionary dynamics of gut microbiomes and host immunity under natural selection.