High-temperature stress response in the liver of Trachinotus ovatus: a cascade of oxidative stress, immunity, and bile acid metabolic reprogramming

Abstract

Fish exhibit a high degree of susceptibility to shifts in thermal conditions within the water. The liver is central to metabolic homeostasis and immune defense, and its physiological stability is critical for fish health. The present study evaluated the hepatic physiological responses of Trachinotus ovatus following a 7-day exposure to high-temperature (HT) stress, including alterations in histology, oxidative stress, iron homeostasis, inflammation, immunity, apoptosis, and bile acid (BA) metabolism. HT stress induced alterations in liver histology and disrupted redox homeostasis, accompanied by enhanced Nrf2-mediated antioxidant signaling and changes in antioxidant defense enzyme activities and peroxide levels. Iron homeostasis and lipid peroxide defense exhibited complex alterations, including Fe levels and NCOA4 expression were increased, accompanied by compensatory upregulation of iron-homeostasis genes (FTH1, FPN1, and NFS1) and antioxidant defense genes (GPx4, SLC7A11, and p53). However, reduced lipid peroxidation products (LPO and MDA) suggested that these changes reflected regulatory adaptation rather than the execution of ferroptosis. HT stress induced hepatic inflammatory and immune responses, characterized by activation of pro-inflammatory signaling, dysregulated anti-inflammatory regulation, downregulation of IL-8 expression, and downregulation of the immunoglobulin genes IgM and IgT. Apoptosis-related genes showed divergent expression patterns, with CHOP, Casp-9, and Casp-3 being upregulated, whereas CytC was downregulated. Furthermore, BA metabolism was affected, as shown by reductions in total BA pool size and free BA levels, along with the upregulated expression of BA metabolism-related genes (FXR, SULT1, and UGT8). Three metabolites, cholic acid, chenodeoxycholic acid, and 7-ketolithocholic acid were identified as potential biomarkers. Collectively, these findings suggest that HT stress impaired hepatic physiological homeostasis in T. ovatus, accompanied by tissue architecture disruption, redox imbalance, inflammatory responses, immune suppression, BA metabolic remodeling, and coordinated changes in iron homeostasis and apoptosis-related regulatory pathways.

Keywords

High-temperature stress / Trachinotus ovatus / Oxidative stress / Physiological response / Bile acid metabolism

References

[1] Alfons MS, Ibrahim AThA, Harabawy ASA, Al-salahy MB, Badr G. Cytoprotective effect of propolis on heat stress induces alteration to histological, ultrastructural, and oxidative stress in catfish (Clarias gariepinus). Environ Sci Pollut Res, 2023, 30: 114152-114165.

[2] Alfonso S, Gesto M, Sadoul B. Temperature increase and its effects on fish stress physiology in the context of global warming. J Fish Biol, 2021, 98: 1496-1508.

[3] Bureau of Fisheries of the Ministry of AgricultureChina fishery statistical yearbook, 2025, Beijing: China Agriculture Press

[4] Chen X, Wang Q, Guo Z, Zhao Y, Luo S, Yu T, Zhang D, Wang G. Identification of the Nrf2 in the fathead minnow muscle cell line: role for a regulation in response to H₂O₂ induced the oxidative stress in fish cell. Fish Physiol Biochem, 2020, 46: 1699-1711.

[5] Cheng C, Guo Z, Luo S, Wang A. Effects of high temperature on biochemical parameters, oxidative stress, DNA damage and apoptosis of pufferfish (Takifugu obscurus). Ecotoxicol Environ Saf, 2018, 150: 190-198.

[6] Elbialy ZI, Salah AS, Elsheshtawy A, Elkatatny NM, Fouad AM, Abo-Al-Ela HG. Differential tissue regulation of nrf2/keap1 crosstalk in response to Aeromonas infection in nile tilapia: a comparative study. Aquacult Int, 2024, 32: 545-562.

[7] Ern R, Andreassen AH, Jutfelt F. Physiological mechanisms of acute upper thermal tolerance in fish. Physiology (Bethesda), 2023, 38: 141-158.

[8] Fan K, Hua X, Liu Y, Zhang Z, Li X, Liu Y, Liu P. HSP70 gene expression responses to the temperature stress in pufferfish (Takifugu rubripes). Biosci Biotechnol Biochem, 2021, 85: 1088-1096.

[9] Faught E, Schaaf MJM. Molecular mechanisms of the stress-induced regulation of the inflammatory response in fish. Gen Comp Endocrinol, 2024, 345. 114387

[10] Fujii J, Osaki T, Soma Y, Matsuda Y. Critical roles of the cysteine–glutathione axis in the production of γ-glutamyl peptides in the nervous system. Int J Mol Sci, 2023, 24. 8044

[11] Gao F, Shi X, Pei C, Zhao X, Zhu L, Zhang J, Li L, Li C, Kong X. The role of ferroptosis in fish inflammation. Rev Aquacult, 2023, 15: 318-332.

[12] Guo H, Li W, Zhu K, Liu B, Zhang N, Liu B, Yang J, Zhang D. Pathology, enzyme activity and immune responses after Cryptocaryon irritans infection of golden pompano Trachinotus ovatus (Linnaeus 1758). J Mar Sci Eng, 2023, 11: 262.

[13] Guo K, Zhang R, Luo L, Wang S, Xu W, Zhao Z. Effects of thermal stress on the antioxidant capacity, blood biochemistry, intestinal microbiota and metabolomic responses of Luciobarbus capito. Antioxidants, 2023, 12: 198.

[14] Han M, Luo M, Yang R. Impact of temperature on survival and spinal development of golden pompano Trachinotus ovatus (Linnaeus 1758). Aquacult Rep, 2020, 18. 100556

[15] Hansen JD, Landis ED, Phillips RB. Discovery of a unique Ig heavy-chain isotype (IgT) in rainbow trout: implications for a distinctive B cell developmental pathway in teleost fish. Proc Natl Acad Sci, 2005, 102: 6919-6924.

[16] He F, Ru X, Wen T. NRF2, a transcription factor for stress response and beyond. Int J Mol Sci, 2020, 21: 4777.

[17] Hu Q, Lu J, Yang Y, Li D, Liu J. Acute thermal stress reduces skeletal muscle growth and quality in gibel carp (Carassius gibelio). Water, 2023, 15. 2706

[18] Huang Y, Sun H, Dong J, Zhang J, Wang H, Yang L, Li Y, Wang Y. Novel identification of mixed infection of Lactococcus garvieae and Cryptocaryon irritans isolated from cultured Trachinotus ovatus in China. PLoS ONE, 2024, 19. e0301674

[19] Huang X, Yang Y, Bai Y, Yang S, Chen B, Zhang L, Liu L, Tao J, Tu C, Lin L, Qin Z. Foodborne iron overload induces oxidative stress and causes mitochondrial damage in the liver of grass carp (Ctenopharyngodon idellus). Aquaculture, 2025, 595. 741690

[20] Janasik B, Reszka E, Stanislawska M, Jablonska E, Kuras R, Wieczorek E, Malachowska B, Fendler W, Wasowicz W. Effect of arsenic exposure on NRF2-KEAP1 pathway and epigenetic modification. Biol Trace Elem Res, 2018, 185: 11-19.

[21] Kastrinou Lampou V, Poller B, Huth F, Fischer A, Kullak-Ublick GA, Arand M, Schadt HS, Camenisch G. Novel insights into bile acid detoxification via CYP, UGT and SULT enzymes. Toxicol Vitro, 2023, 87. 105533

[22] Kaur A, Ali S, Brraich OS, Siva C, Pandey PK. State of thermal tolerance in an endangered Himalayan fish Tor putitora revealed by expression modulation in environmental stress related genes. Sci Rep, 2025, 15. 5025

[23] Klak K, Maciuszek M, Pijanowski L, Marcinkowska M, Homa J, Verburg-van Kemenade BML, Rakus K, Chadzinska M. Evolutionarily conserved mechanisms regulating stress-induced neutrophil redistribution in fish. Front Immunol, 2024, 15. 1330995

[24] Kuciński M, Liszewski T, Własow T, Wiśniewska A, Fopp-Bayat D. Histological and transcriptomic characterization of full-thickness skin wound healing in maraena whitefish (Coregonus maraena bloch, 1779). Int J Mol Sci, 2025, 26. 8315

[25] Lee SH, Moniruzzaman M, Farris N, Min T, Bai SC. Interactive effect of dietary gamma-aminobutyric acid (GABA) and water temperature on growth performance, blood plasma indices, heat shock proteins and GABAergic gene expression in juvenile olive flounder Paralichthys olivaceus. Metabolites, 2023, 13: 619.

[26] Li DK, Chaudhari SN, Lee Y, Sojoodi M, Adhikari AA, Zukerberg L, Shroff S, Barrett SC, Tanabe K, Chung RT, Devlin AS. Inhibition of microbial deconjugation of micellar bile acids protects against intestinal permeability and liver injury. Sci Adv, 2022, 8. eabo2794

[27] Li Q, Zhang J, Wang H, Niu S, Wu R, Tang B, Wang Q, Liang Z, Liang Y. Transcriptomic response of the liver tissue in Trachinotus ovatus to acute heat stress. Animals, 2023, 13: 2053.

[28] Li R, Amenyogbe E, Lu Y, Jin J, Xie R, Huang J. Effects of low-temperature stress on intestinal structure, enzyme activities and metabolomic analysis of juvenile golden pompano (Trachinotus ovatus). Front Mar Sci, 2023, 10. 1114120

[29] Lin Z, Cai Z, Li L, Wei Y, Ling Q. c-jun N-terminal kinase 1/P53 signaling mediates intrinsic apoptosis of largemouth bass (Micropterus salmoides) hepatocytes under heat stress. Sci Total Environ, 2024, 947. 174664

[30] Liu E, Zhao X, Li C, Wang Y, Li L, Zhu H, Ling Q. Effects of acute heat stress on liver damage, apoptosis and inflammation of pikeperch (Sander lucioperca). J Therm Biol, 2022, 106. 103251

[31] Liu H, Yang Y, Yu Y, Feng J, Bao X, Zhao J, Yu H. Astragaloside IV improved antioxidative stress capacity and related gene expression of the Keap1-Nrf2 pathway in grass carp (Ctenopharyngodon idella) hepatocytes under heat stress. J Fish Biol, 2022, 101: 262-268.

[32] Liu C, Gao Y, Xu X, Jin X, Zhang Y, Xu Q, Ding H, Li B, Du F, Li L, Zhong M, Zhu J, Zhang G. Bile acids inhibit ferroptosis sensitivity through activating farnesoid X receptor in gastric cancer cells. World J Gastroenterol, 2024, 30: 485-498.

[33] Liu Y, Tian C, Yang Z, Huang C, Jiao K, Yang L, Duan C, Zhang Z, Li G. Effects of chronic heat stress on growth, apoptosis, antioxidant enzymes, transcriptomic profiles, and immune-related genes of Hong Kong catfish (Clarias fuscus). Animals (Basel), 2024, 14. 1006

[34] Liu J, Li F, Zeng Q, Hu W, Yang L, Luo S, Li D, Deng Y. Dysregulated bile acid metabolism drives lipid peroxidation and ferroptosis in NAFLD: therapeutic potential for traditional Chinese medicine. Front Pharmacol, 2025, 16. 1669805

[35] Livak KJ, Schmittgen TD. Analysis of relative gene expression data using real-time quantitative PCR and the 2^−ΔΔC_T method. Methods (San Diego Calif), 2001, 25: 402-408.

[36] Long X, He K, Zhang M, Li M, Wang Z, Wang C, Dong X, Shao J, Gan L, Hu X, Jiang H. Temporal correlations of ferroptosis, inflammation and oxidative stress under acute ammonia exposure in brain tissue of yellow catfish (Pelteobagrus fulvidraco). Comp Biochem Physiol C, 2023, 271. 109693

[37] Long Z, Qin H, Huang Z, Xu A, Ye Y, Li Z. Effects of heat stress on physiological parameters, biochemical parameters and expression of heat stress protein gene in Lateolabrax maculatus. J Therm Biol, 2023, 115. 103606

[38] Ma C, Zhu X, Liao M, Dong S, Dong Y. Heat sensitivity of mariculture species in China. ICES J Mar Sci, 2021, 78: 2922-2930.

[39] Ma W, Sun X, Zhu Y, Liu N. Metformin attenuates hyperlipidaemia-associated vascular calcification through anti-ferroptotic effects. Free Radic Biol Med, 2021, 165: 229-242.

[40] Meech R, Mubarokah N, Shivasami A, Rogers A, Nair PC, Hu DG, McKinnon RA, Mackenzie PI. A novel function for UDP glycosyltransferase 8: galactosidation of bile acids. Mol Pharmacol, 2015, 87: 442-450.

[41] Perino A, Schoonjans K. Metabolic messengers: bile acids. Nat Metab, 2022, 4: 416-423.

[42] Sun Y, Wen H, Tian Y, Mao X, Li X, Li J, Hu Y, Liu Y, Li J, Li Y. HSP90 and HSP70 families in Lateolabrax maculatus: genome-wide identification, molecular characterization, and expression profiles in response to various environmental stressors. Front Physiol, 2021, 12. 784803

[43] Sun H, Ren J, Ma X, Wang X, Zhang A, Zhou H. Aeromonas hydrophila effector Hcp1 triggers ferroptosis in teleost splenic macrophages via NCOA4-mediated ferritinophagy. Fish Shellfish Immunol, 2025, 164. 110459

[44] Tschuck J, Theilacker L, Rothenaigner I, Weiß SAI, Akdogan B, Lam VT, Müller C, Graf R, Brandner S, Pütz C, Rieder T, Schmitt-Kopplin P, Vincendeau M, Zischka H, Schorpp K, Hadian K. Farnesoid X receptor activation by bile acids suppresses lipid peroxidation and ferroptosis. Nat Commun, 2023, 14. 6908

[45] Volkoff H, Rønnestad I. Effects of temperature on feeding and digestive processes in fish. Temperature (Austin), 2020, 7: 307-320.

[46] Wang L, Sagada G, Wang C, Liu R, Li Q, Zhang C, Yan Y. Exogenous bile acids regulate energy metabolism and improve the health condition of farmed fish. Aquaculture, 2023, 562. 738852

[47] Wang Q, Wu R, Ji J, Zhang J, Niu S, Tang B, Miao B, Liang Z. Integrated transcriptomics and metabolomics reveal changes in cell homeostasis and energy metabolism in Trachinotus ovatus in response to acute hypoxic stress. Int J Mol Sci, 2024, 25. 1054

[48] Wu Y, Lin Y, Lin B, Huang Y, Yu Z, Ma Y, Feng Y, Chen Q, Gao A, Shu H. Effects of hypoxia and reoxygenation on energy metabolism, immune response, and apoptosis in orange-spotted grouper (Epinephelus coioides). Front Mar Sci, 2024, 11: 1495068.

[49] Wu N, Yu S, Wei X, Yang L, Zhang X. Multiple roles of bile acids in ferroptosis regulation: opportunities for disease therapy. Pharmacol Res, 2026, 228. 108224

[50] Xia X, Cheng Z, He B, Liu H, Liu M, Hu J, Lei L, Wang L, Bai Y. Ferroptosis in aquaculture research. Aquaculture, 2021, 541. 736760

[51] Xu H, Wang Z, Li Y, Xu Z. The distribution and function of teleost IgT. Fish Shellfish Immunol, 2024, 144. 109281

[52] Xu L, Bi Y, Xu Y, Wu Y, Du X, Mou Y, Chen J (2021) Suppression of CHOP reduces neuronal apoptosis and rescues cognitive impairment induced by intermittent hypoxia by inhibiting Bax and Bak activation. Neural Plast 2021:4090441. https://doi.org/10.1155/2021/4090441

[53] Xv Z, Chen S, Song L, Hu H, Lin S, Long Y. Biochemical, histological and transcriptomic analyses for the immunological organs provide insights into heat stress-induced disease susceptibility in largemouth bass. Sci Total Environ, 2024, 912. 168758

[54] Yan X, Chen Y, Dong X, Tan B, Liu H, Zhang S, Chi S, Yang Q, Liu H, Yang Y. Ammonia toxicity induces oxidative stress, inflammatory response and apoptosis in hybrid grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatu). Front Mar Sci, 2021, 8. 667432

[55] Yang F, Li X, Song K, Wang L, Ma R, Lu K, Zhang C. Accumulation of hydrophobic bile acids mediates chronic heat stress-induced liver-gut axis injury in spotted seabass (Lateolabrax maculatus). Aquaculture, 2026, 625. 744302

[56] Yao T, Wang X, Lu J, Fu S, Cheng C, Ye L. Heat tolerance in Magallana hongkongensis: integrative analysis of DNA damage, antioxidant defense, and stress gene regulation. Antioxidants, 2025, 14. 1075

[57] Yao Y, Wang C (2021) Variations in summer marine heatwaves in the South China Sea. J Geophys Res Oceans 126:e2021JC017792. https://doi.org/10.1029/2021JC017792

[58] Yin F, Yin J, Xie X, Jiang L. Water temperature affects Cryptocaryon irritans development, cryptocaryoniasis occurrence and an auxiliary treatment decision-making webpage. Aquaculture, 2023, 574. 739694

[59] Yousefi M, Hoseini SM, Kulikov EV, Seleznev SB, Petrov AK, Babichev NV, Kochneva MV, Davies SJ. Effects of dietary hyssop, Hyssopus officinalis, extract on physiological and antioxidant responses of rainbow trout, Oncorhynchus mykiss, juveniles to thermal stress. Front Vet Sci, 2022, 9. 1042063

[60] Zeng L, Ai C, Wang Y, Zhang J, Wu C. Abrupt salinity stress induces oxidative stress via the Nrf2-Keap1 signaling pathway in large yellow croaker Pseudosciaena crocea. Fish Physiol Biochem, 2017, 43: 955-964.

[61] Zhang Q, Geng M, Li K, Gao H, Jiao X, Ai K, Wei X, Yang J. TGF-β1 suppresses the T-cell response in teleost fish by initiating Smad3- and Foxp3-mediated transcriptional networks. J Biol Chem, 2022, 299. 102843

[62] Zhang Y, Li Y, Wang R, Wang S, Sun B, Cao D, Sun Z, Lv W, Ma B, Zhang Y. Chronic heat stress caused lipid metabolism disorder and tissue injury in the liver of Huso dauricus via oxidative-stress-mediated ferroptosis. Antioxidants (Basel), 2025, 14: 926-946.

Rights & permissions

The Author(s)