Fig. 2

The effect of PCA on the production of inflammatory cytokines. Serum levels of IL-1β (a), IL-2 (b), IL-6 (c) and TNF-α (d) were measured by using ELISA kits. CTL, a basal diet; AUR, a basal diet containing 50 mg/kg aureomycin; PCA, a basal diet supplemented with 0.4% protocatechuic acid. Data were shown as means ± SD (n = 6), *P < 0.05 compared with CTL, ^#P < 0.05 compared with AUR