High temperature stress has become an important factor that restricted the aquaculture industry. Huso dauricus is a high economic value fish that faced the thermal stress threat. In this study, we set one control group (19℃) and four high-temperature treatment groups (22℃, 25℃, 28℃, 31℃) with 40 fish in each group for continuous 53-day heat exposure. Histological analysis, biochemical detection and transcriptome technology were used to explore the effects of heat stress on the liver structure and functions of juvenile Huso dauricus. It suggeated that heat stress induced hepatic vacuolization, nuclear atrophy, cytoplasmic disintegration in juvenile Huso dauricus with time/temperature-dependent manner. Serum total protein, transaminase, and alkaline phosphatase activities showed significant changes under heat stress. Hepatic reactive oxygen species level and lipid accumulation in heat groups were also observed. In addition, 6433 differentially expressed genes (DEGs) were identified based on the RNA-seq project. Gene Ontology enrichment analysis showed that the DEGs were mainly related to energy metabolism, lipid metabolism and amino acid metabolism. KEGG enrichment and immunohistochemistry analysis showed that ferroptosis and FoxO signaling pathways were significantly enriched. These results demonstrated that thermal stress induced oxidative stress damage in the liver of juvenile Huso dauricus, which triggered lipid metabolism disorder and hepatocyte ferroptosis to disrupt the normal liver functions. In conclusion, our investigation contributed to understand the molecular mechanism on the chronic heat stress-induced injury in Huso dauricus. It is of certain significance for the healthy breeding of Huso dauricus and the protection strategy development of wild population.
 

Huso dauricus; oxidative stress; heat stress; liver; transcriptome