Liver transcriptome analysis reveals genes and pathways involved in the ovarian development in spotted scat (Scatophagus argus).

Scatophagus argus is a highly valuable aquaculture fish. Its artificial breeding faces problems in the induction of high quality eggs, thus necessitating studies on the regulation of ovarian development. As the centre of nutrient metabolism in fish, the liver provides the material basis for ovarian development. However, the molecular mechanism of the liver in ovarian development in S. argus is still unclear. In this study, a transcriptome analysis of adult S. argus livers at different stages of ovarian development (stages II, III and IV) was performed. 410, 1025 and 1867 differentially expressed genes (DEGs) were obtained between stages II and III, stages II and IV and stages III and IV, respectively. In GO and KEGG analyses, DEGs were mostly involved in vitellogenesis and egg envelope formation (e.g., erα, erβ1, vtga, vtgb, vtgc, zp3, zp4a and zp4b), lipid metabolism and energy metabolism (e.g., dagt1, dagt2, lpl, apob, hk1, acly, ogdh, pc, and fbp1), and hormone signaling (e.g., lepa and igfbp1). Additionally, genes that were significantly upregulated in the liver at stage IV of ovarian development, compared to stages II and III, were markedly enriched in steroid biosynthesis and metabolism pathways. These findings provide clues to understanding the mechanisms of liver action in teleost ovarian development.