Acute Heat Stress Disrupts Hepatic Homeostasis and Gut Microbiota in Early-Juvenile Asian Swamp Eels (Monopterus albus)

Abstract

Water temperature is a critical environmental determinant of aquatic organism survival. The Asian swamp eel (Monopterus albus), a major aquaculture species, is highly vulnerable to acute summer heat stress at the early-juvenile stage. Juveniles exposed to 32 °C for 96 h (versus 25 °C controls) exhibited 3498 differentially expressed hepatic genes, with enrichment in amino acid metabolism, immune regulation, and apoptosis pathways; immunity, metabolism, and ion binding were top enriched functions. Key genes linked to immune activation, apoptosis, and metabolic reprogramming were upregulated. Gut 16S rRNA profiling revealed increased microbial diversity and taxonomic shifts indicative of microbiota disruption. These findings show that acute heat stress disrupts hepatic homeostasis via coordinated inflammatory, apoptotic, and metabolic responses while altering gut microbiota, offering an integrated view of thermal resilience mechanisms in early-life-stage teleosts.