Effects of dietary caffeic acid supplement on antioxidant, immunological and liver gene expression responses, and resistance of Nile tilapia, Oreochromis niloticus to Aeromonas veronii

• Published in: Fish & shellfish immunology Vol. 86; pp. 384 - 392
• Main Author: Yilmaz, Sevdan
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-03-2019
• Subjects: Aeromonas veronii; Caffeic acid; Cytokine response; Innate immunity; Nile tilapia; Innate immunity; Aeromonas veronii; Cytokine response; Nile tilapia; Caffeic acid
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2018.11.068

The present study investigated the effects of dietary caffeic acid on haematological, serum biochemical, non-specific immune and liver gene expression responses of Nile tilapia, Oreochromis niloticus. Five experimental groups of fish with mean weights of 89.85 ± 2.5 g were used in the study; three of them were fed with caffeic acid incorporated diets (1 g kg−1-Caf1, 5 g kg−1-Caf5, 10 g kg−1-Caf10), whereas an additive free basal diet served as the control. Additionally, the fifth group was an antibiotic medicated diet (0.02 g kg−1-AMF), prepared with the florfenicol. Dietary caffeic acid especially at 5 g kg−1 significantly increased phagocytic index, potential killing activity, respiratory burst activity, serum myeloperoxidase activity and serum catalase activity. Furthermore, increased levels of immune expression [heat shock protein 70 (HSP70), interleukin 1, beta (IL-1β), tumor necrosis factor (TNF-α), CC-chemokine (CC1), interleukin 8 (IL-8), toll-like receptor 7 (tlr-7), interferon gamma (IFN-γ) and immunoglobulin M (IgM)] and antioxidant related genes [superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)] in the liver of fish fed with 5 g kg−1 caffeic acid. At the end of the 20-day challenge period the survival rates were significantly higher in the Caf5 and AMF groups compared to all other treatment groups.
As a result, feeding Nile tilapia with a diet containing 5 g kg−1 caffeic acid over a period of 60 days might be adequate to improve fish immune parameters, antioxidant status, as well as survival rate against A. veronii, similar to antibiotic treatment. Thus caffeic acid can be suggested as a dietary substitute for antibiotic to prevent A. veronii in tilapia.
•Caffeic acid increased the innate immune responses of Nile Tilapia.•Caffeic acid significantly up-regulated the immune and antioxidant related genes of fish.•Caffeic acid enhanced the protection of Nile Tilapia against Aeromonas veronii.