title: β-Glucan-induced cortisol levels improve the early immune response in matrinxã (Brycon amazonicus).
abstract: This study investigated the role of endogenous cortisol on the innate immune response in matrinxã (Brycon amazonicus) fed with β-glucan, prior to and after stressor exposure and bacterial challenge. For this, we evaluated the serum cortisol and plasma glucose levels, the serum lysozyme levels, the hemolytic activity of the complement system, and the respiratory activity of leukocytes, as well as the number of circulating erythrocytes and leukocytes of fish fed during 15 days with diets containing β-glucan 0.1% (β-G) or β-glucan 0.1% + metyrapone 30 mg kg-1fish (β-G + MTP). Dietary MTP was used to block cortisol production. After feeding, fish were air-exposed during 3 min, to endogenously increase the cortisol levels. Following that, they were challenged with intraperitoneal injection of Aeromonas hydrophila. Results were compared with a positive control group fed with a β-glucan-free diet. A negative control group, also fed with β-glucan-free diet but inoculated with PBS, was established to evaluate the effect of the handling during injection. Fish were sampled prior to the stressor exposure, 30 min after exposure, and 24 h post infection (hpi). Herein we observed that dietary β-G modulated the cortisol profile prior to and after the stressor, increasing the number and activity of leukocytes. Moreover, cortisol showed to be an efficient modulator of both humoral and cellular innate immune system by increasing lysozyme and complement activity, as well as neutrophil and monocyte populations. Our results suggest that β-glucan-induced cortisol increase is one important mechanism to improve the innate immune response in matrinxã.
authors.affiliation: Departamento de Morfologia e Fisiologia Animal, Univ Estadual Paulista UNESP, Via de Acesso Prof. Paulo Donato Castelane, 14.884-900, Jaboticabal, São Paulo, Brazil.
authors.forename: Luz N
authors.initials: LN
authors.lastname: Franco Montoya
authors.affiliation: Departamento de Morfologia e Fisiologia Animal, Univ Estadual Paulista UNESP, Via de Acesso Prof. Paulo Donato Castelane, 14.884-900, Jaboticabal, São Paulo, Brazil.
authors.forename: Talísia P
authors.initials: TP
authors.lastname: Martins
authors.affiliation: Departamento de Morfologia e Fisiologia Animal, Univ Estadual Paulista UNESP, Via de Acesso Prof. Paulo Donato Castelane, 14.884-900, Jaboticabal, São Paulo, Brazil.
authors.forename: Rodrigo Y
authors.initials: RY
authors.lastname: Gimbo
authors.affiliation: Departamento de Morfologia e Fisiologia Animal, Univ Estadual Paulista UNESP, Via de Acesso Prof. Paulo Donato Castelane, 14.884-900, Jaboticabal, São Paulo, Brazil; Centro de Aquicultura da UNESP (CAUNESP), Via de Acesso Prof. Paulo Donato Castelane, Cep. 14.884-900, Jaboticabal, São Paulo, Brazil.
authors.forename: Fábio S
authors.initials: FS
authors.lastname: Zanuzzo
authors.affiliation: Departamento de Morfologia e Fisiologia Animal, Univ Estadual Paulista UNESP, Via de Acesso Prof. Paulo Donato Castelane, 14.884-900, Jaboticabal, São Paulo, Brazil; Centro de Aquicultura da UNESP (CAUNESP), Via de Acesso Prof. Paulo Donato Castelane, Cep. 14.884-900, Jaboticabal, São Paulo, Brazil. Electronic address: bethurb@fcav.unesp.br.
authors.forename: Elisabeth C
authors.initials: EC
authors.lastname: Urbinati
mesh_terms: D016980:Aeromonas hydrophila / Q000502:physiology; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D060126:Characidae; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D005393:Fish Diseases / Q000276:immunology*; D016905:Gram-Negative Bacterial Infections / Q000276:immunology / Q000662:veterinary*; D006854:Hydrocortisone / Q000097:blood*; D007113:Immunity, Innate; D011897:Random Allocation; D047071:beta-Glucans
chemical_list: D047071:beta-Glucans; D006854:Hydrocortisone
keywords: Acute infection; Acute stress; Capture; Early immune defense; Handling