Metabolomics analysis revealed biochemical changes in hepatopancreas and ovary of Litopenaeus vannamei during ovarian maturation

Pacific white shrimp (Litopenaeus vannamei) is one of the most prevalent crustacean species, understanding the metabolomics during gonad maturation in female L. vannamei is important to understand the regulatory mechanism of reproductive process. LC-MS-based untargeted metabolomics was used to identify the metabolite profile in the hepatopancreas and ovary during ovarian maturation in L. vannamei in this study. A total of 452 and 3887 differential metabolites were identified in the hepatopancreas and ovary, respectively. The most enriched pathways of differential metabolites in hepatopancreas were metabolic pathway, linoleic acid metabolism, biosynthesis of unsaturated fatty acids and steroid biosynthesis, and the most enriched pathways identified in the ovary were metabolic pathway, arachidonic acid metabolism, biosynthesis of unsaturated fatty acids, tryptophan metabolism, neuroactive ligand-receptor interaction and steroid biosynthesis. Among these significant differential metabolites, unsaturated fatty acids, such as eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (ARA), decreased significantly in the maturing ovary. Prostaglandins E2 and F2α, the metabolites of ARA, decreased > 50% in the maturing ovary. The contents of vitamin D3 and vitamin E increased more than five-fold at maturing stages, while vitamin A decreased significantly during ovarian maturation. 3-hydroxy-L-kynurenine (3OHKyn), the metabolite of tryptophan and the precursor of ommochrome, accumulated in the maturing ovary. The content of cholesterol and sn-glycerol-3-phosphate also increased in the mature ovary. Furthermore, the expression profiles of genes involved in total cholesterol (TC) and triglyceride (TAG) synthesis were determined to reveal the molecular mechanism of these biosynthesis processes in L. vannamei. The current study revealed the metabolomics profile and found some new metabolites that were critical for ovary development in L. vannamei.