The high temperature stress responses in the hepatopancreas of Litopenaeus vannamei: from immune dysfunction to metabolic remodeling cascade

Sudden fluctuations in environmental temperatures are primarily caused by climate change. Aquatic organisms such as shrimp are poikilothermic animals, making them highly vulnerable to rising water temperatures, which can trigger stress responses and reduce aquaculture productivity. Hepatopancreas is of vital importance to the immunity, metabolism and detoxification of shrimp. In this study, the shrimp <i>Litopenaeus vannamei</i> were continuously exposed to high temperature (HT) stress at 33 °C for 7 days, and the hepatopancreatic histopathology, immune-related indexes, and metabolite patterns were explored. The results showed that HT stress caused abnormal morphological changes in the hepatopancreas of the shrimp, with the hepatic tubules becoming twisted, atrophied, and even ruptured and autolyzed. At the molecular level, stress-related indexes, such as <i>Nrf2</i>, <i>GPx</i>, and <i>HSP70</i> genes expression were increased, while <i>SOD</i> and <i>HSP90</i> genes were decreased; immune-related indexes, such as <i>ALF</i>, <i>Crus</i>, and <i>proPO</i> genes expression were increased, whereas <i>Pen3</i> gene was decreased; inflammation-related genes (<i>JNK</i> and <i>TNFα</i>) and apoptosis-related genes (<i>Casp9</i> and <i>Casp3</i>) expression were increased; autophagy-related indexes, such as <i>Atg3</i>, <i>Atg16</i>, and <i>Beclin1</i> genes expression were increased. Furthermore, HT stress caused the alterations in the metabolic patterns of the hepatopancreas, such as amino acid biosynthesis and metabolism, pentose and glucuronate interconversions, pantothenate and CoA biosynthesis, pyrimidine metabolism, and glycerophospholipid metabolism. Functional metabolites, such as tryptophan, arachidonic acid, cinnamic acid derivatives, vitamins, etc., were identified as biomarker candidates. The results revealed that HT stress induced comprehensive histomorphological and functional impairments in the hepatopancreas of <i>L. vannamei</i> through a cascade of oxidative damage, immune dysregulation, and metabolic disturbance.