Emodin treatment is associated with enhanced resistance to Aeromonas hydrophila and correlates with gut microbiota-immune-metabolic modulation in Yellow River Carp: a multi-omics study.

INTRODUCTION

Aeromonas hydrophila is a major pathogen of bacterial enteritis in aquaculture and a pathogen threatening the safety of fish products; sustainable alternatives to antibiotics are urgently needed. This study explored the potential effects of emodin in Yellow River carp (Cyprinus carpio haematopterus).

METHODS

Yellow River carp were used as a model, and multi-omics approaches (including 16S rRNA/ITS sequencing and untargeted metabolomics) were employed, along with evaluations of survival rate, hepatic and intestinal histopathology, quorum sensing-related virulence gene expression, and serum IgM and lysozyme activities.

RESULTS

Emodin treatment improved survival rate, alleviated pathological damage in the liver and intestine, downregulated quorum sensing-related virulence genes (AhyR, LapA, AerA), and enhanced serum IgM and lysozyme activities. 16S rRNA/ITS sequencing revealed that emodin increased the relative abundance of Ascomycota, Firmicutes, Debaryomyces and Lactococcus, while decreasing genera such as Bosea and Legionella. Untargeted metabolomics indicated marked changes in metabolic profiles. Correlation analysis revealed that the emodin-enriched microbiota was significantly associated with metabolites and the cytokines il-1β and tnf-α.

DISCUSSION: Emodin treatment was associated with enhanced anti-infection ability in Yellow River carp, concomitant with significant alterations in the intestinal microbiota, metabolism, and immune responses, underscoring its great potential as an environmentally friendly immunostimulant in aquaculture.