Dietary protocatechuic acid ameliorates ileal mucosal barrier injury and inflammatory response and improves intestinal microbiota composition in Yellow chickens challenged with Salmonella typhimurium

Salmonella typhimurium (ST) is a com-mon foodborne pathogen that severely affects the health of humans and livestock. Protocatechuic acid (PCA) has been shown to possess anti-inflammatory and anti-bacterial functions. Chickens were used to investigate the effect of PCA on the gut health infected with ST. A total of one hundred eighty, 1-d-old birds were randomly allocated into 3 treatments, each with 6 replicates per treatment and 10 chicks per replicate. Broiler chicks in the control and ST treatment were fed a basal diet, and birds in the PCA+ST treatment received the basal diet with 600 mg/kg PCA. On d 14 and 16 of the trial, broilers in ST and PCA+ST treat-ments received an oral dose of ST, while broilers in CON received an equal amount of PBS. The data were analyzed by the one-way ANOVA. Dietary PCA increased (P < 0.05) final body weight, average daily gain, and feed to gain ratio in ST-challenged Yellow broilers. Protocatechuic acid significantly alleviated ST-induced intestinal mucosal injury reflected in the decreased (P < 0.05) plasma activity of diamine oxidase and ileal apoptosis, with increased (P < 0.05) ileal villus height and villus height/crypt depth. Protocatechuic acid treatment significantly decreased (P < 0.05) ST-induced proinflammatory cytokine (Interleukin-1b, Interleukin-6, Tumor necrosis factor-a, and Interferon-b) content in ileum. Meanwhile, PCA treatment signifi-cantly increased (P < 0.05) the transcript abundances of claudin 1 (CLDN1), zonula occludens-1 (ZO-1), and mucin 2 (MUC2) in ileum, all related to the intes-tinal barrier in ST-challenged Yellow broilers. Addi-tionally, PCA also increased (P < 0.05) the diversity and richness of the cecal microflora as reflected by reduced (P < 0.05) abundance of Bacteroidota, Proteo-bacteria and Escherichia-Shigella, and increased (P < 0.05) abundance of Firmicutes and Lactobacillus in ST-challenged Yellow broilers. These findings indicate that PCA relieves ST-induced loss weight, intestinal barrier injury, inflammatory response, and improves intestinal microbiota composition in Yellow broilers.

Automated summary

The addition of Protocatechuic acid (PCA) in feed has been found to improve gut health in chickens infected with Salmonella typhimurium (ST). PCA enhances body weight, average daily gain, and feed to gain ratio in ST-challenged Yellow broilers. It also reduces intestinal mucosal injury, inflammatory response, and improves the composition of intestinal microbiota.