This study aimed to evaluate the effects of two biomacromolecules, fermented wheat bran polysaccharides (FWBPs) and sodium humate (SH), on growth performance, nutrient digestibility, digestive enzyme activity, antioxidant status, and immunity of broilers. A total of 144 male, one-day-old Arbor Acres broilers were randomly divided into three dietary groups: control (CON), 0.4% FWBPs, and 0.1% SH, with six replicates of eight birds. The FWBPs and SH groups had a greater body weight (BW) at 21 and 42 d, average daily weight gain (ADG) in the starter period, average daily feed intake (ADFI) in the overall period, and feed-to-gain ratio (F:G) in the grower period. However, the ADFI was decreased by FWBPs supplementation and increased by SH supplementation in the grower period. The dry matter (DM) and organic matter (OM) digestibility were higher in the SH group at 21 d. At 21 d, the FWBPs group had an increased duodenal trypsin and serum glutathione peroxidase (GSH-Px) activity and immunoglobulin M (IgM) concentration, and a decreased liver malondialdehyde (MDA) concentration. The SH group had increased duodenal lipase activity, serum IgM, and interleukin-2 concentrations but decreased liver MDA concentrations. At 42 d, FWBPs and SH supplementation decreased duodenal trypsin and chymotrypsin and serum superoxide dismutase activity. Jejunum chymotrypsin activity and liver MDA content were decreased in the SH group. In conclusion, dietary FWBPs or SH supplementation during the starter period can improve growth performance and nutrient digestibility and enhance antioxidant capacity and immunity of broilers.