title: Influence of temperature in thermal and oxidative stress responses in estuarine fish.
abstract: The influence of increasing temperatures in thermal and oxidative stress responses were studied in the muscle of several estuarine fish species (Diplodus vulgaris, Diplodus sargus, Dicentrarchus labrax, Gobius niger and Liza ramada). Selected fish were collected in July at the Tagus estuary (24±0.9°C; salinity of 30±4‰; pH=8). Fish were subjected to a temperature increase of 1°C.h(-1) until they reached their Critical Thermal Maximum (CTMax), starting at 24°C (control temperature). Muscle samples were collected during the trial and results showed that oxidative stress biomarkers are highly sensitive to temperature. Results from stress oxidative enzymes show alterations with increasing temperature in all tested species. Catalase (CAT; EC 1.11.1.6) activity significantly increased in L. ramada, D. labrax and decreased in D. vulgaris. Glutathione S-transferase (GST; EC 2.5.1.18) activity increased in L. ramada, D. sargus, D. vulgaris, and D. labrax. In G. niger it showed a cycle of increase-decrease. Lipid peroxidation (LPO) increased in L. ramada, D. sargus and D. labrax. With respect to correlation analysis (Pearson; Spearman r), the results showed that oxidation products and antioxidant defenses were correlated in L. ramada (LPO-CAT and LPO-GST, D. sargus (LPO-CAT), and D. labrax (LPO-CAT). Oxidative biomarkers were correlated with thermal stress biomarker (Hsp70) in L. ramada (CAT-Hsp70), D. vulgaris (LPO-Hsp70), D. labrax (GST-Hsp70) and G. niger (LPO-Hsp70). In conclusion, oxidative stress does occur with increasing temperatures and there seems to be a relation between thermal stress response and oxidative stress response. The results suggest that oxidative stress biomarkers should be applied with caution, particularly in field multi-species/multi-environment studies.
authors.affiliation: Centro de Oceanografia, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal. dianamadeira@netcabo.pt
authors.forename: D
authors.initials: D
authors.lastname: Madeira
authors.forename: L
authors.initials: L
authors.lastname: Narciso
authors.forename: H N
authors.initials: HN
authors.lastname: Cabral
authors.forename: C
authors.initials: C
authors.lastname: Vinagre
authors.forename: M S
authors.initials: MS
authors.lastname: Diniz
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D063366:Estuaries; D029941:Fish Proteins / Q000378:metabolism; D005399:Fishes / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D018869:Heat-Shock Response; D015227:Lipid Peroxidation; D018482:Muscle, Skeletal / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress
chemical_list: D015415:Biomarkers; D029941:Fish Proteins; D018840:HSP70 Heat-Shock Proteins; D002374:Catalase; D005982:Glutathione Transferase
keywords: Biomarkers; Estuary; Fish; Oxidative stress; Thermal stress