Abstract
Dietary fatty acids have been shown to exert a clear effect on the stress response, modulating the release of cortisol. The role of fatty acids on the expression of steroidogenic genes has been described in mammals, but little is known in fish. The effect of different fatty acids on the release of cortisol and expression of stress-related genes of European sea bass (Dicentrarchus labrax) head kidney, induced by a pulse of adenocorticotrophin hormone (ACTH), was studied. Tissue was maintained in superfusion with 60 min of incubation with EPA, DHA, arachidonic acid (ARA), linoleic acid or α-linolenic acid (ALA) during 490 min. Cortisol was measured by RIA. The quantification of stress-related genes transcripts was conducted by One-Step TaqMan real-time RT-PCR. There was an effect of the type of fatty acid on the ACTH-induced release of cortisol, values from ALA treatment being elevated within all of the experimental period. The expression of some steroidogenic genes, such as the steroidogenic acute regulatory protein (StAR) and c-fos, were affected by fatty acids, ALA increasing the expression of StAR after 1 h of ACTH stimulation whereas DHA, ARA and ALA increased the expression of c-fos after 20 min. ARA increased expression of the 11β-hydroxylase gene. Expression of heat shock protein 70 (HSP70) was increased in all the experimental treatments except for ARA. Results corroborate previous studies of the effect of different fatty acids on the release of cortisol in marine fish and demonstrate that those effects are mediated by alteration of the expression of steroidogenic genes.
Highlights
Dietary fatty acids have been shown to exert a clear effect on the stress response, modulating the release of cortisol
Basal cortisol values were obtained after the stabilisation period (180 min) and no significant differences were found among values of different fatty acid treatments
After adenocorticotrophin hormone (ACTH) stimulation, cortisol values increased in all the experimental groups, the values obtained for head kidney from the EPA, DHA, linoleic acid (LA) and acid or α-linolenic acid (ALA) treatments being significantly higher (P < 0·05) when compared with the control group after 20 min of ACTH stimulation
Summary
Dietary fatty acids have been shown to exert a clear effect on the stress response, modulating the release of cortisol. The effect of different fatty acids on the release of cortisol and expression of stress-related genes of European sea bass (Dicentrarchus labrax) head kidney, induced by a pulse of adenocorticotrophin hormone (ACTH), was studied. There was an effect of the type of fatty acid on the ACTH-induced release of cortisol, values from ALA treatment being elevated within all of the experimental period. Results corroborate previous studies of the effect of different fatty acids on the release of cortisol in marine fish and demonstrate that those effects are mediated by alteration of the expression of steroidogenic genes. There are other pathways described in fish[4], independent of cAMP activation, including protein kinase C activation via stimulation of angiotensin II or acetylcholine with a final activation of genes involved in steroidogenesis, such as steroidogenic acute. The limited availability of fish oil to fulfil the increased demand in aquafeeds has induced the necessity to replace this oil by other oils, of marine or terrestrial origin[10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
