Dietary vitamin C deficiency depresses the growth, head kidney and spleen immunity and structural integrity by regulating NF-κB, TOR, Nrf2, apoptosis and MLCK signaling in young grass carp (Ctenopharyngodon idella)

This study investigated the effects of dietary vitamin C on the growth, and head kidney, spleen and skin immunity, structural integrity and related signaling molecules mRNA expression levels of young grass carp (Ctenopharyngodon idella). A total of 540 grass carp (264.37 ± 0.66 g) were fed six diets with graded levels of vitamin C (2.9, 44.2, 89.1, 133.8, 179.4 and 224.5 mg/kg diet) for 10 weeks. Subsequently, a challenge test was conducted by injection of Aeromonas hydrophila and the survival rate recorded for 14 days. The results indicated that compared with optimal vitamin C supplementation, vitamin C deficiency (2.9 mg/kg diet) decreased lysozyme (LA) and acid phosphatase (ACP) activities, and complement 3 and complement 4 (C4) contents (P < 0.05), down-regulated the mRNA levels of antimicrobial peptides [liver expressed antimicrobial peptide (LEAP) 2A, LEAP-2B, hepcidin, β-defensin] and anti-inflammatory cytokines-related factors, interleukin (IL) 4/13A, IL-4/13B (only in head kidney), IL-10, IL-11, transforming growth factor (TGF) β1, TGF-β2, inhibitor of κBα and eIF4E-binding protein 1 (P < 0.05), and up-regulated pro-inflammatory cytokines-related factors, tumor necrosis factor α, interferon γ2, IL-1β, IL-6, IL-8, IL-12 P35 (only in spleen), IL-12 P40, IL-15, IL-17D, nuclear factor κB p65, IκB kinases (IKKα, IKKβ, IKKγ), target of rapamycin and ribosomal protein S6 kinase 1 mRNA levels (P < 0.05) in the head kidney and spleen under i...
Source: Fish and Shellfish Immunology - Category: Biology Source Type: research