Β-glucan modulates cortisol levels in stressed pacu (Piaractus mesopotamicus) inoculated with heat-killed Aeromonas hydrophila. Issue 93 (October 2019)

• Record Type: Journal Article
• Authors: Marinho de Mello, Mariana Maluli; de Fátima Pereira de Faria, Camila; Zanuzzo, Fábio Sabbadin; Urbinati, Elisabeth Criscuolo
• Is Part Of: Fish & shellfish immunology. Issue 93(2019)
• Page Start: 1076
• Page End: 1083
• Publication Date: 2019-10
• Subjects: Transport -- Stress -- Immunostimulant -- Immunomodulation; Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2019.07.068
• Languages: English
• ISSNs: 1050-4648

Abstract

Abstract: In this study, we show that β-glucan can modulate cortisol release in fish. We simulated a common situation in aquaculture: the transport of fish followed by contact with an opportunistic pathogen and observed what effect glucan had on the immune and stress response in these conditions. Pacu ( Piaractus mesopotamicus ) were fed with a diet containing β-glucan (0.1%) for 15 days prior to transport followed by an injection with heat-killed Aeromonas hydrophila. We sampled fish before transport, at arrival and at 3 and 24 h after bacterial injection. β-Glucans are used in aquaculture and have a known immunostimulatory effect, which was observed in this study. The results showed that β-glucan modulated the plasma cortisol levels differently by increasing these levels up to 24 h after transport and preventing the increase caused by bacterial inoculum injection. In addition, β-glucan enhanced the activity of the complement system at 24 h and reduced the monocytes and lymphocytes number in peripheral blood at 3 and 24 h after bacterial inoculation. Our results suggest that β-glucan modulated a bidirectional interaction between the stress and the immune responses. The modulation of cortisol levels and the immunostimulation by β-glucan at different moments in our study suggest the compound has a protective effect by avoiding higher levels of the hormone and improving resistance against bacterial infection in pacu. These results add evidence to support the use of β-glucan as an immunomodulator in the aquaculture industry. Highlights: β-glucan increased the cortisol levels during the stress response to transport. β-glucan reduced the cortisol levels in stressed fish inoculated with Aeromonas hydrophila. β-glucan enhanced the hemolytic activity of the complement system depressed by stress. β-glucan reduced the circulating monocytes and lymphocytes after bacterial inoculum.