LAUSR

&NA; This experiment was conducted with 144 male Arbor Acre broilers (one d old, weighing 45.6 ± 1.3 g) to determine protective effects of Forsythia suspensa extract (FSE) against breast muscle oxidative injury induced by transport stress (TS). The birds were randomly allotted to one of 4 treatments in a 2 × 2 factorial arrangement. The treatments consisted of broilers fed diets supplemented without or with FSE (100 mg/kg) and challenged without or with TS for 3 h before slaughter. Transport stress increased live BW loss of broilers (P < 0.05), and the adverse effect was attenuated by FSE (P < 0.05). Serum levels of corticoserone and lactate were increased for broilers after transportation (P < 0.05), whereas these parameters were not affected by FSE. After slaughter, neither breast muscle pH value at 45 min and 24 h postmortem nor 24 h drip loss value was influenced by TS or FSE, whereas TS increased the value of pH decline within 24 h postmortem (P < 0.05). Transportation decreased redness and increased yellowness value of breast muscle in broilers (P < 0.05), and FSE tended to have (P = 0.06) or had the converse changes (P < 0.05). Comparing with non‐transported birds, the birds subjected to transportation had greater malondialdehyde (MDA) content and avUCP mRNA expression (P < 0.05) and lower 1,1‐diphenyl‐2‐picryl‐hydrazyl (DPPH) radical scavenging activity (P < 0.05) in breast muscle, whereas the birds supplemented with FSE had lower MDA content (P < 0.05) and greater DPPH radical scavenging activity (P < 0.05). Transport caused decreases (P < 0.05) in total antioxidant capacity and glutathione peroxidase activity, and the decreases were improved by FSE (P < 0.05). Collectively, live BW loss and breast muscle oxidative injury were increased by TS in broilers and could be attenuated by FSE via directly scavenging free radicals and increased antioxidant capacity. Therefore, FSE could protect broilers against breast muscle oxidative injury induced by TS.