The influence of different substrate culture environments on the intestinal microbial community of <i>Babylonia areolata</i>

This study aimed to evaluate how varying substrate culture environments influence the gut microbial community structure of Babylonia areolata . Three substrate culture environments were established using small ceramic grains (SC), silica sand (SS), and river sand (RS). High-throughput 16S rRNA sequencing was employed to characterize the gut microbial diversity and community structure of B. areolata across the three substrate environments. The results revealed a total of 9,975 OTUs, with 568 shared among all groups. Notably, the SC group exhibited 1,675 unique OTUs, exceeding those observed in the SS and RS groups; The SC group showed higher values for the richness, Simpson, Chao, and ACE indices compared to the SS and RS groups, suggesting that while the ceramic substrate promoted higher microbial abundance, it was associated with lower community diversity. However, these differences in diversity indices among the three groups were not statistically significant. Proteobacteria and Firmicutes overwhelmingly dominated the intestinal microbiota and represented the major phyla across all three substrate groups. At the genus level, the SC group was dominated by Mycoplasma, Psychrobacter, Shewanella, and Pseudoalteromonas. Vibrio, Pseudoalteromonas, and Mycoplasma predominantly inhabited the RS group. In the SS group, dominant genera included Pseudoalteromonas, Mycoplasma, Vibrio, and Burkholderia-Caballeronia-Paraburkholderia. Co-occurrence network analysis indicated that Mycoplasmataceae and Pseudoalteromonadaceae were the most strongly correlated taxa across all groups. These findings demonstrate that substrate composition significantly influences the gut microbial community structure and abundance in B. areolata , with ceramic substrates promoting increased microbial richness. This research provides foundational data and theoretical insights into sustainable aquaculture, disease management, and the development of functional feeds for B. areolata .