Effects of Ban Lian Zi Jin San on intestinal inflammation and barrier function of heat-stressed broilers

Heat stress (HS) in broilers can be an environmental stressor that leads to intestinal inflammation and intestinal barrier damage. In order to examine the effect of Ban Lian Zi Jin San (BLZJS) on intestinal inflammation and barrier function in heat-stressed broilers, a model of chronic cyclic HS in broilers was established. A total of 300 twenty-one-day-old broilers were divided into 5 treatments at random. Broilers in 3 BLZJS dosage groups were kept in an ecologically controlled room at 37℃ ± 2℃ for 6 wk, and fed basal diets supplemented with 0.5, 1, and 2% BLZJS. Broilers in HS group were housed in the same room, but fed the basal diets. The findings indicated that supplementation of BLZJS significantly declined serum HS indexes levels (HSP70, HSP90), and increased serum antioxidant capacity (SOD and T-AOC) in broilers (P < 0.05). Besides, supplementation of BLZJS significantly inhibited the expression of HS indexes (HSP70 and HSP90), genes related to TLR4 inflammatory signal pathway (TLR4, MyD88, TRIF, IRAK-4, and NF-κB), inflammatory factors (IL-6 and TNF-α), and upregulated anti-inflammatory cytokines (IL-10) and intestinal tight junction-related genes (Occludin, Claudin-1, and ZO-1) in broiler jejunum (P < 0.05). On the other hand, supplementation of BLZJS could significantly reduce the protein expression of NF-κB and HSP70 in chick jejunum (P < 0.05). In conclusion, BLZJS inhibited the activation of TLR4 signal pathway and reduced the production of inflammatory factors, restoring the level of intestinal tight junction protein and protecting jejunal intestinal barrier function in heat-stressed broilers.