Development of Gut Microbiota Composition in Captive Asian Elephants: A Year-Long Analysis

This study aimed to investigate the establishment and maturation of gut microbiota in captive Asian elephant calves during their first year of life, with a focus on the influence of maternal factors and dietary transitions. By analyzing monthly fecal and meconium samples from five healthy infants using 16S rRNA gene sequencing, we characterized microbial shifts associated with milk feeding, dietary fiber introduction, and the onset of coprophagy. The results showed that microbial diversity was highest at birth, declined during early infancy, and expanded again as calves adopted a fibrous diet, with Firmicutes, Actinobacteriota, and Bacteroidota dominating throughout. The emergence of Methanobrevibacter around seven to eight months highlighted dietary adaptation, while overall microbial communities increasingly resembled those of adults by one year of age, albeit with lower richness. These findings provide critical insights into gut microbial development in elephant calves and highlight the role of diet in shaping microbial colonization, supporting improved health management and conservation strategies in captive populations.