Intestinal and Aquatic Microbiota Composition, Diversity, and Function in Glyptosternon maculatum

Abstract

Variations in aquatic environmental characteristics and food resource availability across different habitats lead to habitat-specific differentiation in the structure and function of the fish digestive system. As a key functional component in maintaining host health, fish gut microbiota is critically important for the healthy and sustainable development of aquaculture. In this study, we investigated the gut microbiota of Glyptosternon maculatum from wild, domesticated, and farmed groups, as well as the microbiota in their habitat water, using 16S rRNA gene sequencing. Alpha diversity analysis (one-way analysis of variance (ANOVA) with Tukey’s HSD post hoc test for multiple comparisons) revealed that the Shannon and Simpson indices of the gut microbiota were significantly higher in the wild group than in the domesticated and farmed groups (p  < 0.05), indicating greater community diversity in the wild population. Beta diversity analysis (Adonis test based on Bray-Curtis distances) demonstrated significant separation between the wild group and the other two groups in both intestinal (R² = 0.132, p = 0.026) and water (R² = 0.645, p = 0.002) microbiota, while the domesticated and farmed groups showed similar microbial community structures in both gut and water samples. Mantel tests revealed that pH and dissolved oxygen (DO) were significantly correlated with gut microbial community composition, suggesting these environmental factors may influence the intestinal microbiota of G. maculatum. Functional prediction analysis (PICRUSt2) revealed habitat-associated differences in metabolic functions of the gut microbiota, particularly in amino acid and carbohydrate metabolism pathways. In summary, these findings provide baseline data for understanding habitat-related microbial community shifts in G. maculatum and may inform future conservation and management strategies for this species.