Comparative metagenomic analysis of gut microbiomes in Yunnan ponies and Dutch warmblood horses.

Introduction: The Yunnan pony is an officially protected pony breed in China. However, its gut microbiome characteristics remain largely unexplored. This study aimed to compare the gut microbiome and antibiotic resistance genes (ARGs) profiles between Yunnan ponies and Dutch warmblood horses. Methodology: A total of 14 fresh fecal samples were collected from Yunnan ponies and Dutch warmblood horses. Metagenomic sequencing was employed to comprehensively analyze and compare the gut microbial composition, function, and ARGs profiles between the two breeds. Results: The results showed no significant differences between the two breeds in core phylum composition or overall microbial diversity. A total of 146 bacterial genera were identified with significant differences at the genus level. Functional analysis revealed that the gut microbiota of Yunnan ponies was significantly enriched in pathways related to carbohydrate metabolism and pectin degradation, which are involved in basic energy acquisition. In contrast, Dutch warmblood horses were more enriched in host immune interaction pathways such as Toll-like receptor signaling. Analysis of ARGs indicated that while there was no difference in the overall diversity of ARGs between the two groups. Their association networks with specific bacterial hosts were markedly distinct, and the dominant ARG subtypes differed. Discussion: This study provides a descriptive characterization of the gut microbiome of Yunnan ponies, offering baseline data for future research on the conservation of this genetic resource and its health management in breeding.