Molecular and physiological adaptations to low-salinity stress in penaeid shrimp: a focus on Litopenaeus vannamei and Penaeus monodon.

Penaeid shrimp are economically important in global aquaculture. Rising demand has expanded shrimp farming and supported coastal economies. Low-salinity (hyposalinity) stress is a major constraint that impairs physiology and reduces growth, survival, and productivity. This review explores the adaptive mechanisms employed by penaeid shrimp in response to salinity stress and the consequent challenges faced by the aquaculture sector. Penaeid shrimp exhibit adaptive responses to salinity stress through a variety of physiological and molecular mechanisms, including ion regulation, osmoregulation, antioxidant defense, and the activation of signaling pathways. While these mechanisms are critical, they necessitate further in-depth investigation. This review synthesizes recent advancements in the understanding of penaeid shrimp adaptation to salinity stress, encompassing salinity signal perception, the activation of calcium and phospholipid signaling, signal transduction, and the regulation of gene expression. Additionally, it provides a comprehensive overview of the physiological and molecular responses of penaeid shrimp to salinity stress. The paper also discusses the potential implications of these findings for the aquaculture industry, particularly for improving climate-change resilience under increasingly frequent and unpredictable salinity fluctuations.