Tissue‐Specific Mechanism of Fat Distribution in Teleosts: Comparative Analysis Between Two Carnivorous Marine Species, Golden Pompano ( <i>Trachinotus ovatus</i> ) and Spotted Sea Bass ( <i>Lateolabrax maculatus</i> )

The molecular mechanisms underlying species-specific lipid distribution patterns in teleosts remain poorly understood. This study investigated two marine carnivorous species with distinct fat deposition characteristics: the golden pompano (<i>Trachinotus ovatus</i>), which stores lipid in the liver and muscle, and the spotted sea bass (<i>Lateolabrax maculatus</i>), which primarily stores fat in the abdominal adipose tissue. Juveniles (~10.0 g) were fed three iso-nitrogenous diets (45% protein) with graded lipid levels (12%, 14%, and 16%) for 8 weeks. Two-way analysis of variance (ANOVA) analyses revealed significant species × diet interactions affecting lipid distribution (<i>p</i> < 0.05). Golden pompano exhibited higher hepatic/muscular crude lipid and triglyceride (TG) levels than spotted sea bass, whereas abdominal TG content and abdominal fat index (AFI) were lower (<i>p</i> < 0.05). Transcriptomics and qPCR revealed tissue-specific regulatory mechanisms: there was an upregulation of hepatic and muscular fatty acid transport genes (<i>ldlr</i> and <i>fabp</i>), synthesis (<i>g6pd</i>), and deposition (<i>dgat1</i>) with increasing dietary lipid in golden pompano. Additionally, enhanced adipogenesis (<i>c/ebpα</i> and <i>pparγ</i>) and TG storage (<i>dgat1</i>) were observed in the abdominal adipose of spotted sea bass. These findings indicate that lipid accumulation in the liver and muscle of golden pompano is driven by increased fatty acid transport and lipogenesis, while spotted sea bass prioritizes abdominal adipogenesis. This study provides novel insights into the regulation of lipid metabolism in teleosts, with implications for aquaculture feed optimization.