Transcriptome analysis unveils adaptation strategies in silver pomfret (Pampus argenteus) gills under hypoxic conditions.

The silver pomfret (Pampus argenteus) is an economically valuable and highly sought-after table fish in China. In recent years, commercial farming of silver pomfret has been successfully developed in the country. However, silver pomfret is highly sensitive to environmental stress, and hypoxia-induced stress can lead to significant economic losses in aquaculture. This study investigated the transcriptomic response of silver pomfret gills under normal oxygen conditions (G0) and after hypoxic exposure for 6 h (G6) and 24 h (G24). Hypoxia exposure induced gill remodeling, characterized by increased gill lamellar height and a reduction in interlamellar cell mass (ILCM). Oxidative stress and antioxidant responses were significantly upregulated after 24 h of hypoxia exposure. Additionally, many downregulated genes were significantly enriched in pathways related to cardiac muscle contraction and calcium signaling, leading to impaired gill musculature contraction and reduced oxygen uptake under hypoxic conditions. Key signal transduction pathways, including HIF- 1, Apelin, and MAPK signaling, were identified as critical pathways in response to hypoxia. Furthermore, hypoxia tended to suppress the immune system and disrupted endoplasmic reticulum homeostasis and protein processing in the gills of silver pomfret. In summary, this study demonstrates that hypoxia disrupts gill function in silver pomfret and provides insights into hypoxia adaptation mechanisms in teleosts.