Algae-derived polysaccharides supplementation ameliorates heat stress-induced impairment of bursa of Fabricius via modulating NF-κB signaling pathway in broilers

ABSTRACT This study aimed to investigate the protective effects of dietary algae-derived polysaccharides (ADP) from Enteromorpha prolifera against heat stress (HS)-induced bursa of Fabricius injure in broilers, and to elucidate the molecular mechanisms underlying the protective effect. A total of 144 eight-week-old male yellow-feathered broilers were randomly allocated into three treatments of six replicates each (eight broilers per replicate): thermoneutral zone group (TN, fed basal diet); heat stress group (HS, fed basal diet); heat stress + ADP group (HSA, basal diet supplemented with 1000 mg/kg ADP). Broilers in TN group were raised at 23.6 ± 1.8 °C during the whole study. Broilers in HS and HSA groups were exposed to 33.2 ± 1.5 °C for 10 h/day. The experimental period lasted for four weeks. The results showed that HS and dietary ADP had no significant effects on bursa of Fabricius index (P > 0.05). HS exposure increased the apoptosis rate of bursa of Fabricius (P