The Pacific white shrimp (Penaeus vannamei) is one of the most economically important shrimp species worldwide, known for its fast growth and adaptability to aquaculture. However, the species exhibits significant sexual dimorphism, as females typically grow larger than males. This has generated growing interest in cultivating all-female shrimp populations to maximize productivity and profitability in the aquaculture industry.
Recent research has explored the potential of 17β-estradiol (E2), a key female sex hormone, to induce sex reversal in male shrimp, transforming them into functional females. An innovative study published in BMC Genomics by scientists from the Institute of Oceanology at the Chinese Academy of Sciences sheds light on the molecular mechanisms behind this process, providing new insights into the role of the neuroendocrine system in sex reversal.
The role of 17β-Estradiol in sex reversal
A promising method to achieve all-female populations is hormone-induced sex reversal, particularly using 17β-estradiol (E2). E2 is a sex hormone that plays a crucial role in female sexual development, and studies have shown that it can induce feminization in various aquatic species. However, the mechanisms behind how E2 induces sex reversal in crustaceans are not yet fully understood.
The study, conducted by Wang, investigated the effects of prolonged E2 immersion on the neuroendocrine system of P. vannamei. Researchers exposed postlarval shrimp to E2 at a concentration of 2 mg/L from postlarva stage 5 (PL5) to PL85. The results were striking: the female-to-male ratio in the treated group shifted to 2.56:1, compared to a nearly 1:1 ratio in the control group.
Approximately 47.93% of genetically male shrimp experienced sex reversal, becoming phenotypically female (neofemales).
Impact on growth and survival
While E2 exposure did not significantly affect shrimp survival rates, it had a notable impact on growth. E2-treated males that did not undergo sex reversal (EM group) exhibited slower growth compared to control males (CM group). This growth inhibition was attributed to potential neuronal damage caused by excessive neurotransmission, which disrupted key signaling pathways such as PI3K-Akt and the cell cycle.
In contrast, neofemales (NF group) did not exhibit significant growth delays, suggesting that sex reversal may confer some resistance to the growth-inhibiting effects of E2.
Transcriptomic insights into the neuroendocrine system
The study employed RNA sequencing (RNA-seq) to analyze the transcriptomes of neuroendocrine tissues, including the eyestalk ganglia, brain, thoracic ganglia, and ventral nerve cord.
Researchers identified 1,795 differentially expressed genes (DEGs) among the CM, EM, and NF groups. Notably, the EM group showed downregulation of genes involved in the cell cycle and PI3K-Akt signaling pathways, which are crucial for growth and cell proliferation. This downregulation likely contributed to the observed growth inhibition in the EM group.
In the NF group, the study found significant downregulation of pathways related to neuroactive ligand-receptor interactions and dopaminergic synapses. These pathways are essential for neurotransmission and neuroplasticity, suggesting that E2 may influence gender identity and morphological differences by modulating neuroregulator binding and signaling.
Steroidogenesis and insulin signaling
One of the study’s key findings was the activation of steroidogenesis in the NF group. Genes involved in steroid hormone biosynthesis, such as StAR3, 3βHSD, and 17βHSD, were significantly upregulated, indicating elevated estrogen levels and a possible autoregulatory mechanism to maintain estrogen homeostasis. This activation of steroidogenesis is likely a critical factor in the success of E2-induced sex reversal.
Conversely, the insulin signaling pathway was inhibited in the NF group. Insulin-like receptors, including IGFBP and ILPR, were downregulated, which may affect the signaling of the insulin-like androgenic gland hormone (IAG). IAG is essential for male differentiation in crustaceans, and its alteration could contribute to the feminization observed in the NF group.
Implications for the shrimp farming industry
The findings of this study have significant implications for the shrimp farming industry. By understanding the molecular mechanisms behind E2-induced sex reversal, it may be possible to develop more effective strategies for producing all-female shrimp populations. This could lead to increased productivity and profitability, as well as environmental benefits, such as reducing the risk of invasive shrimp populations from escaped individuals.
Conclusion
Wang’s study represents a significant advancement in our understanding of E2’s effects on the neuroendocrine system of P. vannamei. The research highlights the complex interplay between neurotransmission, steroidogenesis, and insulin signaling in the sex reversal process. These insights not only deepen our understanding of crustacean biology but also pave the way for innovative approaches in shrimp aquaculture, complementing other techniques such as shrimp hybridization to enhance productivity.
As the demand for sustainable and efficient aquaculture practices continues to grow, studies like this will be crucial in developing new technologies.
The study was funded by CARS-48, the Taishan Scholars Program for FHL, and the Shandong Postdoctoral Science Foundation.
Contact
Yang Yu
Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Oceanology, Chinese Academy of Sciences
Qingdao, China
Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center
Qingdao, China
Email: yuyang@qdio.ac.cn
Reference (open access)
Wang, T., Li, S., Yu, Y. et al. Sex reversal induced by 17β-estradiol may be achieved by regulating the neuroendocrine system of the Pacific white shrimp Penaeus vannamei. BMC Genomics 26, 86 (2025). https://doi.org/10.1186/s12864-025-11236-2
