Effects of dietary algae-derived polysaccharides (ADP) on relative mRNA expression of Nrf2 pathway related genes of bursa of Fabricius in broilers under heat stress. TN, thermoneutral zone group (23.6 ± 1.8°C); HS, heat stress group (33.2 ± 1.5°C for 10 h/day); HSA, heat stress + ADP group (supplemented with 1,000 mg/kg ADP); Nrf2, nuclear factor erythroid 2-related factor 2; HO-1, heme oxygenase-1; SOD, superoxide dismutase; GPx, glutathione peroxidase; CAT, catalase; GSTT, glutathione S-transferase theta; GSTO, glutathione S-transferase omega; GSTA, glutathione S-transferase alpha. All data were expressed as means ± SEM (n = 6). abDifferent superscript letters indicate significant differences (P < 0.05).