Figure 3.

Effect of PFA supplementation on circulating cytokines markers in HS broilers. The relative gene expression of IL-6 (A), IL-18 (B), TNFα (C), and CRP (D) was determined by qPCR and analyzed by 2^–ΔΔCt method using C-TN group as a calibrator. Main effects of diet, temperature, and the interaction are presented next to each graph. Data are presented as mean ± SEM (n = 6-8 birds/group). Different letters indicate significant difference at P < 0.05. Abbreviations: CRP, C-reactive protein; HS, heat stress; IL, interleukin; PFA, phytogenic feed additive; TNFα, tumor necrosis factor alpha; TN, thermoneutral.