Abstract：
Commercial culture of channel catfish (Ictalurus punctatus) occurs in earthen ponds that are characterized by diel swings in dissolved oxygen concentration that can fall to severe levels of hypoxia, which can suppress appetite and lead to suboptimal growth. Given the significance of the hypothalamus in regulating these processes in other fishes, an investigation into the hypothalamus transcriptome was conducted to identify specific genes and expression patterns responding to hypoxia. Channel catfish in normoxic water were compared with catfish subjected to 12 h of hypoxia (20% oxygen saturation; 1.8 mg O2/L; 27°C) followed by 12 h of recovery in normoxia to mimic 24 h in a catfish aquaculture pond. Fish were sampled at 0-, 6-, 12-, 18-, and 24-h timepoints, with the 6- and 12-h samplings occurring during hypoxia. A total of 190 genes were differentially expressed during the experiment, with most occurring during hypoxia and returning to baseline values within 6 h of normoxia. Differentially expressed genes were sorted by function into Gene Ontology biological processes and revealed that most were categorized as \"response to hypoxia,\" \"sprouting angiogenesis,\" and \"cellular response to xenobiotic stimulus.\" The patterns of gene expression reported here suggest that transcriptome responses to hypoxia are broad and quickly reversibly with the onset of normoxia. Although no genes commonly reported to modulate appetite were found to be differentially expressed in this experiment, several candidates were identified for future studies investigating the interplay between hypoxia and appetite in channel catfish, including adm, igfbp1a, igfbp7, and stc2b.NEW & NOTEWORTHY Channel catfish are an economically important species that experience diel episodic periods of hypoxia that can reduce appetite. This is the first study to investigate their transcriptome from the hypothalamus in a simulated 24-h span in a commercial catfish pond, with 12 h of hypoxia and 12 h of normoxia. The research revealed functional groups of genes relating to hypoxia, angiogenesis, and glycolysis as well as individual target genes possibly involved in appetite regulation.
摘要：
通道cat鱼（Ictaluruspunctatus）的商业培养发生在土塘中，其特征是溶解氧浓度的diel波动，可能会下降到严重的缺氧水平，从而抑制食欲并导致次优生长。鉴于下丘脑在调节其他鱼类这些过程中的重要性，对下丘脑转录组进行了研究，以鉴定响应缺氧的特定基因和表达模式。将常氧水中的Channel鱼与经过12小时缺氧（20％氧饱和度；1.8mgO2/L；27°C），然后在常氧条件下恢复12小时，以模拟cat鱼养殖池塘中的24小时。鱼在0-，6-，12-，18-,和24小时的时间点，在缺氧期间进行6小时和12小时的采样。共有190个基因在实验过程中差异表达,大多数发生在缺氧期间，并在常氧后6小时内恢复到基线值。差异表达的基因通过功能分类为基因本体论生物学过程，并显示大多数被归类为“对缺氧的反应”，“发芽血管生成”，和“细胞对异种生物刺激的反应”。此处报道的基因表达模式表明，随着常氧的开始，对缺氧的转录组反应广泛且迅速可逆。尽管在本实验中没有发现通常报道的调节食欲的基因差异表达，几个候选人被确定为未来的研究调查缺氧和食欲之间的相互作用的通道cat鱼，包括ADM,igfbp1a,igfbp7和stc2b.
