Moderate air exposure induces AMPK-associated metabolic remodeling linked to enhanced umami taste in shrimp (Penaeus vannamei) muscle

Air exposure is the primary stressor during waterless transport of live shrimp, affects shrimp metabolism and is closely associated with quality deterioration, particularly the loss of umami taste. However, the regulatory pathways underlying air exposure induced changes in umami-related metabolites in shrimp muscle and their actual impact on flesh taste remain unclear. Here, we investigated adenosine monophosphate-activated protein kinase (AMPK)-regulated metabolic responses in Pacific white shrimp ( Penaeus vannamei ) during air exposure and assessed their implications for flesh taste. Air exposure increased cytosolic Ca 2+ and the adenosine monophosphate (AMP)/adenosine triphosphate (ATP) ratio, indicating activation of upstream AMPK signals. AMPK responses were tissue- and time-dependent: liver kinase B1 (LKB1) and Ca 2+ /calmodulin-dependent protein kinase kinase (CaMKK) and AMPK transcription peaked earlier in muscle than in hepatopancreas. AMPK reached its maximum at 8 h in muscle but at 12 h in hepatopancreas, consistent with enhanced glycolysis to compensate for energy deficiency. In parallel, ATP degradation and protein catabolism promoted the accumulation of umami-related metabolites in muscle, including inosine monophosphate (IMP) and free amino acids. Electronic tongue and equivalent umami concentration (EUC) analyses showed that 4 h exposure produced the most favorable taste profile, with increased umami and sweetness and reduced bitterness. Overall, moderate air exposure was associated with enhanced umami development, accompanied by AMPK-associated metabolic remodeling. This study updates the understanding of air exposure effects on umami taste of shrimp muscle contributing to the optimization of waterless transportation practices of aquatic animals.