AUTHOR=Saetan Jirawat , Duangprom Supawadee , Songkoomkrong Sineenart , Amonruttanapun Prateep , Phanaksri Teva , Surinlert Piyaporn , Samhuay Chompunut , Tamtin Montakan , Suwansa-Ard Saowaros , Cummins Scott F. , Sobhon Prasert , Kornthong Napamanee 

TITLE=Potent ovarian development as being stimulated by cocktail hormone in the female Scylla olivacea

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 10 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2023.1286789

DOI=10.3389/fmars.2023.1286789

ISSN=2296-7745

ABSTRACT=Mud crab Scylla olivacea is widely cultured for its economic value, but reproduction issues limit its production. Vitellogenesis-inhibiting hormone (VIH), serotonin (5-HT), and gonadotropin releasing hormone (GnRH) are important neurohormones in crustaceans that control reproduction. Mimicking crab hormone stimulation in reproduction is scarcely reported. Comparing the single hormone and multiple hormone approaches to crab hormonal control in S. olivacea is limited. In situ hybridization showed that injection of dsRNA-VIH could abolish its gene expression in neuronal clusters of female S. olivacea eyestalk, potentially reducing its inhibitory effects on ovarian maturation. This was confirmed by assessing ovarian gonadosomatic index (GSI), hemolymph vitellogenin (Vg), an indicator of vitellogenesis, and gonad histology with dsRNA-VIH and 5-HT/GnRH combinations. Based on our findings, we demonstrated that the administration of dsRNA-VIH resulted in a significant increase in the gonadosomatic index (GSI) on the 14th and 28th days post-treatment. The combination cocktail, however, consisting of 5-HT + GnRH + dsRNA-VIH at days 14 and 28, and GnRH + dsRNA-VIH at day 28, was the most efficacious in increasing GSI and enhancing crab ovarian maturation. The upregulation of hemolymph Vg levels was observed solely on the 28th day following treatment with dsRNA-VIH, 5-HT + GnRH + dsRNA-VIH, and GnRH + dsRNA-VIH. Differential gene expression analysis using quantitative RNA-sequencing of the neural tissues (brain and ventral nerve cord), identified a significant upregulation of certain receptors (5-HTR, GnRHR, LHR, and FSHR), neuropeptides (sNPF, NPF1, NPF2, SIFamide, AKH/Crz, CHH, and RPCH), downstream reproductive-related genes (FAMeT, ESULT, progesterone-like protein) , and prostanoid-related genes (phospholipase A and C, COX, Thromboxane A synthase, prostaglandin D, E and F synthases) following treatments, particularly dsRNA-VIH + GnRH and/or 5-HT-injected individuals. The upregulation of prostaglandin E synthase and estrogen sulfotransferase genes was confirmed by real-time PCR. Since the construction and propagation of dsRNA-VIH is deemed to be costly, its lower dose application supplemented with synthetic GnRH and/or 5-HT may be an alternative approach to ensure female S. olivacea attain sufficient reproductive fecundity in aquaculture. Furthermore, we proposed that the administration of multiple hormones in crabs may better emulate the physiological conditions of crustaceans in their natural habitat.