Significantly elevated protein levels of α-SMA (Fig. 2A, B), a gold standard fibrosis marker, and mRNA levels of fibrotic genes, such as Acta2, Col1α1, Col1α2, Col2α, Mmp2, and Mmp9, as well as proinflammatory genes, i.e. TNFα, IL-8, IL-10 and IL-1β, further illustrated the occurrence of liver fibrosis in fish fed HCHFD diet (Supplementary Fig. S1A, B) or challenged with CCL4 (Supplementary Fig. S1C, D). This evidence concerns the gene IL1B and fibrosis.