Abstract
Litsea citrata essential oil (LC-EO) has been proposed as a potential natural additive for mitigating heat stress in aquaculture species. This study evaluated the association between LC-EO exposure, survival performance, and transcriptomic responses of Artemia franciscana under normal (28°C) and heat-stress (34°C) conditions. Supplementation with 0.005% LC-EO was associated with significantly improved survival under heat stress. Transcriptomic analysis identified 318 differentially expressed genes (DEGs) under normal conditions and 764 DEGs under heat stress. Functional enrichment analyses indicated that LC-EO exposure was associated with altered expression of genes involved in detoxification, antioxidant-related processes, immune regulation, nucleotide metabolism, and cellular maintenance, with enriched pathways including lysosome, glutathione metabolism, cytochrome P450, purine and pyrimidine metabolism, and RNA polymerase. Quantitative RT-PCR validation of eight selected DEGs showed strong concordance with RNA-Seq data (R = 0.83–0.94, P < 0.001), supporting the reliability of the transcriptomic dataset. Collectively, these results suggest that LC-EO exposure is associated with transcriptional modulation of stress-responsive pathways under heat stress, generating testable hypotheses regarding its potential role in enhancing thermal tolerance in A. franciscana . Functional validation will be required to determine whether these transcriptomic changes translate into causal physiological protection.