Short-term and long-term effects of transient exogenous cortisol manipulation on oxidative stress in juvenile brown trout

Abstract

In the wild, animals are exposed to a growing number of stressors with increasing frequency and intensity, as a result of human activities and human-induced environmental change. To fully understand how wild organisms are affected by stressors, it is crucial to understand the physiology that underlies an organism's response to a stressor. Prolonged levels of elevated glucocorticoids are associated with a state of chronic stress and decreased fitness. Exogenous glucocorticoid manipulation reduces an individual's ability to forage, avoid predators and grow, thereby limiting the resources available for physiological functions like defence against oxidative stress. Using brown trout (Salmo trutta), we evaluated the short-term (2 weeks) and long-term (4 months over winter) effects of exogenous cortisol manipulations (versus relevant shams and controls) on the oxidative status of wild juveniles. Cortisol caused an increase in glutathione over a 2 week period and appeared to reduce glutathione over winter. Cortisol treatment did not affect oxidative stress levels or low molecular weight antioxidants. Cortisol caused a significant decrease in growth rates but did not affect predation risk. Over-winter survival in the stream was associated with low levels of oxidative stress and glutathione. Thus, oxidative stress may be a mechanism by which elevated cortisol causes negative physiological effects.

Metabolic costs of altered growth trajectories across life transitions in amphibians

“…At metamorphosis, individuals compensating for delayed hatching had lower MDA levels, which may indicate scarce lipid peroxidation favoured by antioxidant activities. Intriguingly, those individuals also had higher levels of GSH, which plays an essential role in counteracting free radical production in vertebrates (Birnie‐Gauvin et al, ). Higher GR activity may have generated large amounts of GSH, which can reduce damages in lipids (Hanna, ).…”

“…Alternatively, lower MDA levels may indicate a lower accumulation of fat reserves in larvae (Burraco, Iglesias-Carrasco, Cabido, & Gomez-Mestre, 2018;Pérez-Rodríguez et al, 2015), reflected also in the positive relationship between MDA levels and body mass at this point. which plays an essential role in counteracting free radical production in vertebrates (Birnie-Gauvin et al, 2017). Higher GR activity may have generated large amounts of GSH, which can reduce damages in lipids (Hanna, 2012).…”

Melatonin promotes secondary hair follicle development of early postnatal cashmere goat and improves cashmere quantity and quality by enhancing antioxidant capacity and suppressing apoptosis

“…Studies in Merino sheep showed that the initiation and maturation of secondary follicles during fetal life and early postnatal period were inhibited by malnutrition, this may be attributed to the reactive oxygen species (ROS) production and oxidative stress induced by malnutrition . In addition, studies on Merino sheep showed that secondary follicle development during fetal and early postnatal period under normal conditions was suppressed by plasma cortisol, a stress‐related hormone that was reported to induce ROS production and oxidative stress …”

“…[23][24][25] In addition, studies on Merino sheep showed that secondary follicle development during fetal and early postnatal period under normal conditions was suppressed by plasma cortisol, 17,18,26,27 a stress-related hormone that was reported to induce ROS production and oxidative stress. 28,29 Development of secondary follicles involves complex epithelium-mesenchyme interactions between follicular epithelial keratinocytes and underlying mesenchymal cells in the dermis 30,31 and depends on a delicate balance between cell proliferation and apoptosis. 32,33 Excessive ROS generation causes damage to all cellular components including proteins, lipids, and DNA and triggers apoptosis of mesenchymal stem cells (MSCs) and epithelial stem cells that are the progenitors of secondary hair follicle cells.…”

Stress-preventing effects of the anaesthetic agents 2-phenoxyethanol, MS-222, clove oil and metomidate in the Senegalese sole Solea senegalensis

“…Stress is a critical factor in fish health, but its harmful effects are not always immediately visible and may only appear after the medium or long period [9]. This may have adverse economic impacts on fish farming or could confound research findings [10].…”