Comparative Analysis of Bacterial Communities in Soil and Intestines of Fish from Traditional and Modern Rice-Fish Coculture Systems.

To compare the soil and fish intestinal bacterial communities between traditional (TRF) and modern (MRF) rice-fish co-culture system, examining the impact of feed supplementation. High-throughput 16S rRNA gene sequencing was used to assess structure, diversity, composition, and functional predictions in soil and intestinal communities between TRF and MRF systems in Qingtian, Zhejiang Province, China. Key findings revealed that both soil and fish intestinal bacterial communities in the MRF system exhibited higher diversity and richness than those in the TRF. In soil, Pseudomonadota dominated both systems. MRF enriched Bacillota, whereas TRF enriched oligotrophy-linked Acidobacteriota and Chloroflexota. In intestine, TRF was Fusobacteriota-centered with Cetobacterium and Aeromonas dominance. While MRF was more even, with higher Bacillota, Actinomycetota, Clostridium and Mycobacterium. Which consistent with adaptation to formulated feeds. Rice yields remained unchanged, suggesting microbial buffering of nutrient input. Functional prediction (COG) indicated that MRF microbiota were enriched in carbohydrate metabolism and signal transduction, whereas TRF favored biosynthetic pathways. These findings offer insights for sustainable rice-fish co-culture system.