Muscle Cortisol Levels, Expression of Glucocorticoid Receptor and Oxidative Stress Markers in the Teleost Fish Argyrosomus regius Exposed to Transport Stress

Abstract

Fish commercial transport is an ordinary practice in the aquaculture industry. This study aimed to investigate the effect of a 48 h transport stress on stress response of meagre (Argyrosomus regius) juveniles. Radioimmunoassay (RIA) and Real-Time PCR were used to evaluate muscle cortisol levels and to assess glucocorticoid receptor (gr) gene expression in fish muscle and liver, respectively. Presence and localization of various oxidative stress markers were investigated in different tissues by immunohistochemistry. A significant increase in muscle cortisol levels was observed after loading but a significant decrease occurred after 16 h from departure even without returning to control levels. Molecular analysis on stress response revealed an increase in muscle gr expression after fish loading that started decreasing during the travel returning to the control level at the end of the transport. Instead, no differences in liver gr expression were observed along the different sampling points. Immunostaining for heat shock protein 70 (HSP70), 4-hydroxy-2-nonenal (HNE), nitrotyrosine (NT) and 8-hydroxy-2’-deoxyguanosine (8-OHdG) antibodies was detected in several organs. Notably, a higher NT immunostaining intensity was evident in skin and gills of the transported animals with respect to controls. Results demonstrated that cortisol and gr are useful indicators of stressful conditions in transported fish.

Effects of Acute Hypoxic Stress on Physiological and Hepatic Metabolic Responses of Triploid Rainbow Trout (Oncorhynchus mykiss)

“…This treatment can lead to hypoxic stress in fish. When the fish body is stimulated by external adverse stress, a stress hormone, cortisol, is secreted, and its level increases in the blood (Bortoletti et al, 2021). In this study, the plasma cortisol content increased under acute hypoxic stress, which could be considered a sensitive signal of fish stress (Mommsen et al, 1999).…”

Effects of elevated temperature on 8-OHdG expression in the American oyster (Crassostrea virginica): Induction of oxidative stress biomarkers, cellular apoptosis, DNA damage and γH2AX signaling pathways

“…Notably, out of 20 different oxidative products that have been characterized, 8-OHdG is considered the major element of oxidative DNA damage [43] . Numerous studies in recent years have analyzed levels of 8-OHdG in fish and shellfish DNA in relation to environmental pollutants, hypoxia, transport stress, as well as thermal stress [43] , [44] , [45] , [46] , [47] . For example, Gleason et al.…”

Transport and Recovery of Turbot (Scophthalmus maximus) Sedated with MS-222 and Eugenol: Effects on Intermediary Metabolism and Osmoregulation

“…Serum cortisol is one of the most important indicators of stress levels in fish [ 30 ]. Under cold and stressful conditions, serum cortisol levels in fish increase significantly [ 27 ].…”