Transcriptome analysis of liver provides insight into metabolic and translation changes under hypoxia and reoxygenation stress in silver sillago (Sillago sihama).

Hypoxia can lead to adverse effects on growth, reproduction, behavioral activities and survival in fish, and is one of the most critical factors in the aquatic environment. The liver is an important target organ for reducing toxin accumulation and hypoxia in fish. In this study, silver sillago (Sillago sihama) was exposed to normoxia (dissolved oxygen, DO = 8.0 mg/L), hypoxia for 1 h (hypoxia 1 h, DO = 1.5 mg/L), hypoxia for 4 h (hypoxia 4 h, DO = 1.5 mg/L) and reoxygenation for 4 h after hypoxia 4 h (reoxygenation 4 h, DO = 8.0 mg/L). Results showed that the expression of 506, 1721, and 1230 differentially expressed genes (DEGs) (|log2(fold change) > 1.0| and padj < 0.05) were identified at hypoxia 1 h, hypoxia 4 h, and reoxygenation 4 h in the liver, respectively. The enrichment analysis showed that the DEGs were significantly enriched in metabolic and translation changes pathways, including mapk signaling pathway, p53 signaling pathway, fatty acid metabolism, protein export, ribosome biogenesis in eukaryotes. The DEGs of 17 genes validated the RNA-seq results by quantitative real-time PCR (qRT-PCR). This study provides a comprehensive understanding of the transcriptional changes that occur in different hypoxia and insights into the mechanisms of hypoxia adaptation of the liver in S. sihama.