A new study reports that captivity reshapes the gut microbiome of Oriental Pied Hornbills. A new study of Oriental Pied Hornbills (Anthracoceros albirostris) reports that zoo-housed and rescue-rehabilitated individuals carry gut microbial communities that differ sharply from those of wild birds, and that managed birds show altered levels of antibiotic resistance genes. The work, published in the journal Animal Microbiome, used shotgun metagenomic sequencing to compare fecal microbiomes across the three groups.
The gut microbiome is essential for host nutrition, immunity, and environmental adaptation, yet its response to captivity in wild birds remains poorly understood, the authors note. To address that gap, the team compared fecal samples from wild, zoo-housed, and rescue-rehabilitated hornbills, reading the full genetic content of the microbial communities rather than targeting only a single marker gene. That shotgun approach allowed the researchers to profile not just which bacteria were present, but also the functional pathways and antibiotic resistance genes those microbes carried.
The clearest signal emerged in diversity. Wild birds showed the highest alpha diversity, meaning their guts hosted the richest mix of microbial species. Zoo-housed birds sat at the opposite end of the spectrum with the lowest diversity, while rescue-rehabilitated birds fell in between, displaying an intermediate pattern. The three groups differed in alpha diversity, with wild birds highest, zoo-housed birds lowest, and rescue-rehabilitated birds intermediate.
Beyond diversity, the three groups carried distinctly different bacterial profiles. Wild hornbills were enriched in Lactobacillus, Enterococcus, and Akkermansia. Managed birds, by contrast, showed higher abundances of Streptococcus, Weissella, Clostridium, and Ruminococcus. The shift indicates that managed birds carried a different set of bacterial genera at higher abundance than wild birds.
The differences extended into function. When the researchers examined KEGG pathways, standardized catalogs of the metabolic and cellular processes microbes can perform, the profiles of the three groups diverged as well. In other words, the KEGG pathway profiles of the three groups differed, indicating differences in the functional potential of their gut microbial communities.
Perhaps the most consequential finding involved the resistome, the collection of antibiotic resistance genes carried by gut microbes. The study found that ARG classes also differed among the three groups, and the title of the paper states that captivity enriches for these genes.
The authors conclude that these findings indicate zoo housing and rescue rehabilitation reshape the gut microbiome and resistome of Oriental Pied Hornbills.
Subject of Research: How captivity reshapes the gut microbiome and antibiotic resistance genes of Oriental Pied Hornbills
Article Title: Captivity reshapes the gut microbiome and enriches for antibiotic resistance genes in the oriental pied hornbill
Article References: Li, X., Jiang, T., Zhong, Y., Wei, X., Li, X., Zeng, P., Qin, J., Chen, Y., Wu, J., You, Z., Qin, Y., Luo, Z., Yang, D., & Yu, T. (2026). Captivity reshapes the gut microbiome and enriches for antibiotic resistance genes in the oriental pied hornbill. Animal Microbiome. https://doi.org/10.1186/s42523-026-00637-7
Image Credits: AI Generated
DOI: 10.1186/s42523-026-00637-7
Keywords: Oriental Pied Hornbill, gut microbiome, captivity, antibiotic resistance genes, shotgun metagenomics, zoo-housed birds, wildlife rehabilitation, Animal Microbiome, resistome, alpha diversity, conservation, reshapes
News Source: Morgan Morrow. (October 28, 2026). Captivity reshapes gut microbiome and antibiotic resistance genes in oriental pied hornbills, study finds. Scienmag.
