Increasing reproductive capacity in female blue swimmer crabs using vitellogenesis-inhibiting hormone dsRNA

Abstract

Vitellogenesis-inhibiting hormone (VIH) is a key regulatory hormone that suppresses vitellogenin production and inhibits ovarian maturation in various crustaceans. The X-organ sinus gland complex of the eyestalks and the central nervous system (CNS) synthesizes and releases this neuropeptide. Double-stranded RNA (dsRNA) techniques have been employed to silence hormonal target transcripts through RNA interference with target genes. We investigated the impact of dsRNA-VIH on the reproductive function of female blue swimmer crabs, Portunus pelagicus, by evaluating its capacity to inhibit VIH in the eyestalks. A single injection of VIH dsRNA at 0.6 µg/g of body weight was injected every 14 days, which effectively suppressed VIH expression for 14 days after the injection. In the dsRNA-VIH treatment group, both the gonadosomatic index (GSI) and the vitellin (Vn) concentration in the hemolymph increased over time relative to the control groups on days 14 and 28. Moreover, dsRNA-VIH had a stimulatory impact on the expressions of other reproductive-related gene: vitellogenin (Vg), red pigment-concentrating hormone (RPCH), farnesoic acid O-methyltransferase (FAMeT), and estrogen sulfotransferase (ESULT). The findings indicate a progressive rise in the expression levels of these genes in both the brain and ventral nerve cord. Histological analysis also showed that the dsRNA-VIH group had significantly more oocytes in step 4 (Oc4) than the control group. The findings indicate that dsRNA-VIH has the capacity to reduce VIH production in the CNS, which affects the expression of other genes that are implicated in ovarian development in the blue swimmer crab.