Dietary Fagopyrum dibotrys Extract Supplementation: Impacts on Growth Performance, Immune Response, Intestinal Morphology, and Microbial Community in Broiler Chickens Infected with Escherichia coli O157

This study explored the efficacy of dietary Fagopyrum dibotrys extract (FDE) in mitigating Escherichia coli O157 (E. coli) infections in broilers. A total of 240 one-day-old male Shengze 901 broilers were randomly allocated to four groups (with 10 broilers per group): CON (basal diet), COLI (basal diet + E. coli challenge), FDE (basal diet + 500 mg/kg FDE), and FDEC (basal diet + 500 mg/kg FDE + E. coli challenge). The results showed that E. coli challenge reduced the average daily gain (ADG) and average daily feed intake (ADFI), increased the feed conversion ratio (FCR) and cecal E. coli load, impaired the intestinal mucosa, and induced intestinal inflammatory responses (p < 0. 05). FDE supplementation improved growth performance, increased duodenal villus height and villus/crypt ratio; reduced serum interleukin (IL) -1β, tumor necrosis factor-α (TNF-α), diamine oxidase (DAO), and endotoxin levels; and lowered cecal E. coli counts (p < 0. 05). Molecularly, FDE supplementation upregulated Occludin, Claudin-1, and ZO-1 gene expressions, and downregulated jejunal TLR4 and MyD88 mRNA levels. Microbiome analysis revealed that FDE increased the relative abundance of Faecalibacterium and alleviated the E. coli-induced reduction in ClostridiaUCG-014. In conclusion, dietary supplementation with 500 mg/kg FDE could mitigate colibacillosis-related intestinal damage and inflammatory responses.