title: Cortisol response to air exposure in Solea senegalensis post-larvae is affected by dietary arachidonic acid-to-eicosapentaenoic acid ratio.
abstract: An experiment was conducted in order to evaluate the effects of feeding frozen Artemia diets differing in arachidonic acid-to-eicosapentaenoic acid ratios (ARA/EPA) on growth, survival and stress coping ability of Senegalese sole post-larvae (19-31 days after hatch). Two experimental diets presenting high ('High'; 3.0) or low ('Low'; 0.7) ARA/EPA ratios were tested under two rearing conditions: undisturbed (C) and stressed by a 2-min air exposure every two days (S). Growth, survival and basal cortisol levels were similar between groups indicating that independently of dietary ARA/EPA ratios, fish were able to cope with the repeated stress imposed. Also, cortisol levels at 3 h past air exposure were determined in all groups at the end of the experiment. Among fish fed the 'Low' diet, C groups seemed to present a quicker recovery from the acute stress (basal-like levels) than S groups. Repeated stress effects were not apparent in fish fed the 'High' diet and, relative to basal levels, twofold higher cortisol concentrations were detected at 3 h, in both C and S groups. This study suggests the importance of ARA in steroidogenesis regulation and the modulatory role of EPA in this process. Despite the tolerance to a wide range of dietary ARA/EPA as indicated by growth and survival results, acute stress coping response may be more efficient in Senegalese sole post-larvae fed low ARA/EPA ratios and, under these particular conditions, a faster recovery of cortisol to basal values could be indicative of rearing conditions (undisturbed vs. repeatedly stressed).
authors.affiliation: CIMAR/CCMAR, Centro de Ciências do Mar do Algarve, Universidade do Algarve, Faro, Portugal. dimartins@ualg.pt
authors.forename: Dulce Alves
authors.initials: DA
authors.lastname: Martins
authors.forename: Sofia
authors.initials: S
authors.lastname: Engrola
authors.forename: Sofia
authors.initials: S
authors.lastname: Morais
authors.forename: Narcisa
authors.initials: N
authors.lastname: Bandarra
authors.forename: Joana
authors.initials: J
authors.lastname: Coutinho
authors.forename: Manuel
authors.initials: M
authors.lastname: Yúfera
authors.forename: Luis E C
authors.initials: LE
authors.lastname: Conceição
mesh_terms: D000388:Air; D000818:Animals; D016718:Arachidonic Acid / Q000008:administration & dosage*; D001156:Artemia; D004032:Diet; D015118:Eicosapentaenoic Acid / Q000008:administration & dosage*; D005412:Flatfishes / Q000254:growth & development / Q000378:metabolism*; D006854:Hydrocortisone / Q000378:metabolism*; D013312:Stress, Physiological / Q000187:drug effects*
chemical_list: D016718:Arachidonic Acid; D015118:Eicosapentaenoic Acid; D006854:Hydrocortisone