Abstract
Actinopterygians, ray-finned fishes, represent the most diverse and extensively studied fish class, comprising over 30,000 species. The gut microbiome of Actinopterygians plays a critical role in host behaviour and immune function, driving increasing research interest in this area. The Minich et al. dataset comprises samples from multiple fish orders in diverse environments. For this study, four orders–Perciformes, Blenniiformes, Centrarchiformes, and Labriformes–in rocky reef environments within Actinopterygians were selected from Minich et al. dataset for comparative analysis, as no previous research has focused specifically on these orders. The V4 region of the 16S rRNA gene was utilized to address this research gap. Analyses included Alpha and Beta Diversity, Indicator Species, Core Microbiome, ANCOM-BC, and Functional Pathway analyses to assess compositional and functional variation of gut microbiome between the four orders. Results indicated minimal differences in Alpha and Beta Diversity among four fish orders. Indicator species were identified in all four orders except Perciformes. Core Microbiome Analysis revealed numerous order-specific genera; however, ANCOM-BC detected no significant differences in relative abundance. Functional pathway analysis demonstrated notable metabolic trends between Blenniiformes and Perciformes as well as Centrarchiformes and Perciformes, with limited divergence observed between Labriformes and Perciformes. These findings suggest that compositions of gut microbiome between selected four orders could be similar yet may display significant differences in gut microbiome metabolic pathways.