Comparative metabolomics analysis of ovarian developmental stages in Macrobrachium nipponense.

Rapid sexual maturity of female Macrobrachium nipponense is a severe problem for the aquaculture industry. To date, there have been only transcriptome studies investigating ovarian development, and studies using other tools, such as metabolomics are lacking. Metabolomics reveals changes in the level of metabolites in tissues in relation to current physiological characteristics, and can yield valuable insight into the growth and development of organisms. In this study, we systematically analyzed 15 samples from five different ovarian developmental stages in M. nipponense to learn more about how metabolites change over reproduction. Gas chromatography/time-of-flight mass spectroscopy revealed an array of different compounds and 83-162 pathways depending on the stage. Furthermore, 89 metabolites and 14 pathways were significantly different across stages. It is hypothesized that N-acetyl-N-formyl-5-methoxykynurenamine, ascorbate, fructose-2,6-bisphosphate, cortexolone and other metabolites that significantly differed by stage are regulated by hormones and are closely related to ovarian development. However, for other metabolites that changed with development, such as cytidine and xanthine, an association with ovarian development has yet to be revealed. Quantitative polymerase chain reaction was used to correlate gene changes to metabolites in the pathway for biosynthesis of plant secondary metabolites. We found that the TCA cycle rate may be the cause of female miniaturization during the reproductive period, and that the control of fatty acid content via aquaculture nutrition may be an exogenous tool for regulatory control of maturation. This study provides a systematic and comprehensive metabolomics analysis of ovarian development in M. nipponense and lays a foundation for addressing the problem of rapid sexual maturity.