Abstract
This study investigated the effects of fermented-feed diets on growth performance, immune status, and antioxidant responses in laying hen chicks and the underlying molecular mechanism, specifically, the role of the nuclear factor-κB (NF-κB) signaling pathway. A total of 80 healthy 14-day-old laying hen chicks were randomly divided into 4 treatments: basal diet (CON); basal diet supplemented with 7.5% fermented feed (FD); FD diet plus the NF-κB inhibitor BAY 11-7082 (FD + BAY); and FD diet plus the NF-κB inhibitor JSH-23 (FD + JSH). The NF-κB inhibitors were administered by intraperitoneal injection. The experiment lasted 21 D. Fermented feed supplementation significantly increased the body weight and average body weight gain of laying hen chicks but significantly decreased the feed conversion ratio. Additionally, fermented feed supplementation significantly increased mitogen-activated T-cell and B-cell proliferation in the peripheral blood, as well as elevated the serum concentrations of interleukin (IL)-1, IL-2, IL-4, IL-6, and tumor necrosis factor (TNF-α); however, NF-κB inhibition significantly reduced T-cell proliferation and serum IL-1, IL-6, and TNF-α levels. The levels of IgA, IgG, IgM, and Newcastle disease virus antibody in the serum were significantly increased by the addition of fermented feed. Furthermore, fermented feed supplementation significantly improved antioxidant function, as indicated by the increases of total antioxidant capacity, total superoxide dismutase activity, and glutathione peroxidase activity and the decrease of malonaldehyde level. However, NF-κB inhibition reversed these changes. Western blot analysis showed that fermented feed treatment increased splenic IκB kinase β and NF-κB protein levels, whereas these increases were prevented by NF-κB inhibition. In conclusion, fermented feed improves the growth performance, immune function, and antioxidant capacity of laying hen chicks. Fermented feed-induced modulation of T-cell proliferation, T helper type 1 and T helper type 2 cytokine production, and antioxidation is associated with NF-κB activation.