A comparative analysis of serum biochemistry, gene expression, and gut microbiota in domestication-susceptible and domestication-resistant mandarin fish (Siniperca chuatsi).

The feeding behavior of mandarin fish (Siniperca chuatsi) is unique in that it exclusively preys on live fish throughout its life. Feed-based mandarin fish production has become central to aquaculture, yet domestication success remains low. This study examines intrinsic factors underlying poor feed acceptance in mandarin fish, alongside traits of domestication-susceptible individuals (group A) through a comprehensive comparison. The results showed that: compared to domestication-resistant mandarin fish (group B): (1) the glucose content and amylase activity in the serum of group A are significantly levels higher; (2) compared with domestication-resistant mandarin fish (group B), domestication-susceptible fish (group A) showed significantly higher serum glucose content and amylase activity. Glycolipid metabolism-related genes, including phosphofructokinase (pfk), phosphoenolpyruvate carboxykinase (pepck), glutamic-pyruvic transaminase (gpt), and lipoprotein lipase (lpl), were significantly upregulated in the liver of group A. In the brain, orexigenic genes, including agouti-related peptide (agrp) and neuropeptide Y (npy), were upregulated, whereas anorexigenic genes, including cocaine- and amphetamine-regulated transcript (cart) and pro-opiomelanocortin (pomc), were downregulated in group A. Taste receptor genes, including t1r1 and t1r3, were downregulated in the tongue and lips of group A. Retinal function-related genes, including etinol dehydrogenase 8(rdh8), cellular retinol-binding protein (crbp), and retinal G protein-coupled receptor (rgr), were upregulated in group A, whereas learning/memory-related genes were downregulated; (3) gut microbiota differed markedly between groups, with Firmicutes dominating A and Proteobacteria B; metabolic functions showed greater divergence. These findings reveal differences in metabolic rate, visual/taste perception, and microbiota function, informing artificial selection for domestication.