Higher Dietary Fibre Increases the Faecal Microbiome Diversity of Golden Lion Tamarins (<i>Leontopithecus rosalia</i>).

Abstract

Gut microbiota influences host energetics, metabolic rate, and overall health. Optimising the diet, such as by increasing dietary fibre, is a key strategy for promoting a healthy microbiome and improving host energy balance. In this study, we compared the faecal microbiome of five zoo-housed golden lion tamarins (<i>Leontopithecus rosalia</i>) before and after a dietary fibre increase using 16S rRNA gene sequencing. <i>Prevotella</i>, the most abundant genus, declined significantly (FDR-corrected <i>p</i> < 0.05) following the introduction of a higher-fibre diet. The dietary change also significantly altered the overall gut microbial composition, including the emergence of <i>Eisenbergiella</i> (FDR-adjusted <i>p</i> < 0.05), a butyrate-producing genus whose relative abundance increased from 0% to 0.005% (FDR-adjusted <i>p</i> < 0.05). Given the role of <i>Eisenbergiella</i> in butyrate synthesis, this shift may enhance host energy metabolism and microbial interactions. Additionally, both alpha and beta diversity increased significantly (<i>p</i> < 0.05) after the dietary fibre intervention. A significant reduction in Desulfobacterota (FDR-adjusted <i>p</i> < 0.05) following dietary fibre enrichment was observed, suggesting a shift away from microbial groups that may be associated with pathogenicity or pro-inflammatory effects. Collectively, these changes represent a positive shift in the microbiome, supporting improved host energetics and metabolic health.