PPARA and Disorder of lipid metabolism: Ren et al. (2017) suggested that upregulation of PPARα under a high stocking density enhanced lipid mobilization and utilization in Acipenser schrenckii to cope with crowding stress [86], but Xu et al. (2020) found that PPARα expression was downregulated in Takifugu rubripes under a high density, revealing a decrease in fatty acid β-oxidation and lipid metabolism disorder [87].