Dietary supplementation of bilberry anthocyanin on growth performance, intestinal mucosal barrier and cecal microbes of chickens challenged with Salmonella Typhimurium

Background Anthocyanins (AC) showed positive effects on improving the intestinal health and alleviating intestinal pathogen infections, therefore, an experiment was conducted to explore the protective effects of supplemented AC on Salmonella -infected chickens. Methods A total of 240 hatchling chickens were randomly allocated to 4 treatments, each with 6 replicates. Birds were fed a basal diet supplemented with 0 (CON, and ST), 100 (ACL) and 400 (ACH) mg/kg of AC for d 60, and orally challenged with PBS (CON) or 10 9 CFU/bird (ST, ACL, ACH) Salmonella Typhimurium at d 14 and 16. Results (1) Compared with birds in ST, AC supplementation increased the body weight (BW) at d 18 and the average daily gain (ADG) from d 1 to 18 of the Salmonella -infected chickens ( P < 0.05); (2) AC decreased the number of Salmonella cells in the liver and spleen, the contents of NO in plasma and inflammatory cytokines in ileal mucosa of Salmonella -infected chickens ( P < 0.05); (3) Salmonella infection decreased the ileal villi height, villi height to crypt depth (V/C), and the expression of zonulaoccludins-1 ( ZO -1), claudin-1, occludin, and mucin 2 ( MUC 2) in ileal mucosa. AC supplementation relieved these adverse effects, and decreased ileal crypt depth ( P < 0.05); (4) In cecal microbiota of Salmonella -infected chickens, AC increased ( P < 0.05) the alpha-diversity (Chao1, Pd, Shannon and Sobs indexes) and the relative abundance of Firmicutes, and decreased ( P < 0.05) the relative abundance of Proteobacteria and Bacteroidota and the enrichment of drug antimicrobial resistance, infectious bacterial disease, and immune disease pathways. Conclusions Dietary AC protected chicken against Salmonella infection via inhibiting the Salmonella colonization in liver and spleen, suppressing secretion of inflammatory cytokines, up-regulating the expression of ileal barrier-related genes, and ameliorating the composition and function of cecal microbes. Under conditions here used, 100 mg/kg bilberry anthocyanin was recommended.