Food Deprivation Enhances Disease Resistance: Underlying Mechanisms in Oysters Confronted with Pacific Oyster Mortality Syndrome

Variation in food availability can shape host susceptibility and pathogen virulence, thereby impacting disease outcomes. An ad libitum diet may enhance host physiology and immunity but it can also favor pathogen proliferation. Here, we investigated how food availability (ad libitum vs. starvation) affects interactions between the oyster Magallana gigas and the herpesvirus OsHV-1 µVar initiating the panzootic Pacific Oyster Mortality Syndrome (POMS). We found that starvation reduced oyster susceptibility to POMS. Through a comparative integrative-omics approach, we showed that (1) starvation induces metabolic rate depression, which may limit viral replication by reducing the availability of cellular energy that viruses can hijack, and (2) enhances autophagy and antiviral responses, thereby improving viral control. These results underscore the importance of nutritional status in shaping viral disease outcomes and may inform management strategies in aquaculture systems.