Targeted Lipidomics and Transcriptomics Reveal Key Nutrients Regulating Ovarian Development in Coreius guichenoti

In this study, targeted metabolomics and transcriptomics were applied for the first time to compare fatty acid contents, vitamin levels, and gene expression profiles between Stage II and Stage IV ovaries of LBG. The data revealed a rise in total SFA and PUFA as the ovary progressed from Stage II to Stage IV. The marked increase in n-3 PUFA from 11.5% in Stage II to 26.8% in Stage IV ovaries was primarily attributed to DHA. Despite a reduction in n-6 PUFA, ARA and its metabolism-related fatty acids all increased, suggesting indispensable roles for both ARA and DHA in the vitellogenesis of LBG. Consistent with the changes in fatty acid profiles during ovarian maturation, transcriptome analysis revealed that many upregulated differentially expressed genes (DEGs) showed significant enrichment in fatty acid biosynthesis, arachidonic acid metabolism, and steroid hormone synthesis pathways. The concentrations of VC and VE increased, whereas VA declined during ovarian development from Stage II to Stage IV. Accordingly, many upregulated DEGs exhibited significant enrichment in ascorbate and aldarate metabolism, as well as vitamin digestion and absorption pathways. In addition to VC and VE, our transcriptome data also highlighted the importance of several B vitamins in oocyte development of LBG, warranting further investigation. Overall, these findings suggest that DHA, ARA, VC, and VE are key nutrients governing oocyte maturation in LBG. This study provides a solid theoretical basis for developing broodstock nutritional enhancement strategies in the artificial propagation of LBG.