17β-Estradiol Induced Sex Reversal and Gonadal Transcriptome Analysis in the Oriental River Prawn (Macrobrachium nipponense): Mechanisms, Pathways, and Potential Harm

Abstract

Sex reversal induced by 17β-estradiol (E2) has shown the potential possibility for monoculture technology development. The present study aimed to determine whether dietary supplementation with different concentrations of E2 could induce sex reversal in M. nipponense, and select the sex-related genes by performing the gonadal transcriptome analysis of normal male (M), normal female (FM), sex-reversed male prawns (RM), and unreversed male prawns (NRM). Histology, transcriptome analysis, and qPCR were performed to compare differences in gonad development, key metabolic pathways, and genes. Compared with the control, after 40 days, feeding E2 with 200 mg/kg at PL25 (PL: post-larvae developmental stage) resulted in the highest sex ratio (female: male) of 2.22:1. Histological observations demonstrated the co-existence of testis and ovaries in the same prawn. Male prawns from the NRM group exhibited slower testis development without mature sperm. RNA sequencing revealed 3702 differentially expressed genes (DEGs) between M vs. FM, 3111 between M vs. RM, and 4978 between FM vs. NRM. Retinol metabolism and nucleotide excision repair pathways were identified as the key pathways for sex reversal and sperm maturation, respectively. Sperm gelatinase (SG) was not screened in M vs. NRM, corroborating the results of the slice D. In M vs. RM, reproduction-related genes such as cathepsin C (CatC), heat shock protein cognate (HSP), double-sex (Dsx), and gonadotropin-releasing hormone receptor (GnRH) were expressed differently from the other two groups, indicating that these are involved in the process of sex reversal. Exogenous E2 can induce sex reversal, providing valuable evidence for the establishment of monoculture in this species.

Insulin-like Androgenic Gland Hormone Induced Sex Reversal and Molecular Pathways in Macrobrachium nipponense: Insights into Reproduction, Growth, and Sex Differentiation

“…Histological sections revealed no significant differences between neo-females and dsNRM, when compared to normal dsM and dsFM prawns, with mature sperm in dsNRM and more yolk granules accumulated in dsRM, implying that there was an optimal period for sex reversal. In a previous report, we fed M. nipponense with 17β-estradiol (E 2 ) and found that after a certain period [ 22 ], even high levels of hormones were unable to alter their sex. IAG is responsible for encoding androgens, so we speculate that the sex reversal period in M. nipponense may be influenced by androgen levels in males.…”

“…In addition, Fu et al (2019) conducted research on the CG during different stages of ovarian development and proposed that light signals could impact biological clock gene expression in the nervous system and may reduce steroid hormone secretion [ 33 ]. Notably, we previously used E 2 to reverse sex in male M. nipponense and identified an important sex reversal pathway, “retinol metabolism”, which is also associated with the eyestalks [ 22 ]. In chordates, retinol metabolism plays an important role in the control of cell differentiation, regulation of immune competence, and reproduction during embryogenesis and in the adult organism [ 34 ].…”

“…To address this issue, we used dsIAG to artificially control sex and develop monosex cultivation techniques. Previous studies have indicated that crustaceans possess sex plasticity, but it was a challenge to induce sex reversal when the developmentally sensitive period passed [ 22 , 23 ]. Sex formation in crustaceans involves sex determination and sex differentiation.…”

Role of Mn-LIPA in Sex Hormone Regulation and Gonadal Development in the Oriental River Prawn, Macrobrachium nipponense

“…Observations took place using a stereo microscope (SZX16; Olympus Corporation, Tokyo, Japan). Comparative labeling was performed with various cell types based on cell morphology [21].…”

“…This suggests that genes controlling growth are likely to be involved in sex differentiation and gonadal maturation. A previous study on the mechanism of sex determination in M. nipponense attempted to identify the "steroid biosynthesis" pathway by comparing the transcriptomes of normal female and unreversed male gonads [21]. A Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that the genes in this pathway were significantly enriched in sex determination and gonadal differentiation, and LIPA was one of the differentially regulated genes [22].…”