Comparative Transcriptome Analysis of the Swimbladder Reveals Expression Signatures in Response to Low Oxygen Stress in Channel Catfish

Low oxygen (hypoxia) can have adverse impacts on aquaculture production. Catfish is the leading aquaculture species in the US with relatively high hypoxia tolerance, but hypoxia can still cause huge economic losses to the catfish industry. Studies on hypoxia tolerance, therefore, are important for aquaculture. Fish swimbladder has long been believed to be the homolog of the tetrapod lung, but the molecular evidence is still lacking. In this regard, we conducted RNA- Seq analysis with swimbladder samples of catfish under hypoxic and normal conditions to determine if swimbladder was responsive to low oxygen treatment, and to reveal genes, their expression patterns and pathways involved in response to hypoxia in catfish.