Metabolomics-based analysis on the effects of Salmonella typhimurium infection on cecum metabolism of Wenchang chickens

【Objective】 To clarify the changes of metabolites in cecum contents of Wenchang chickens after Salmonella typhimurium infection，to screen out metabolites highly correlated with Salmonella infection，to reveal the effects of avian salmonellosis on cecum metabolism of Wenchang chickens，and to provide data support for further understanding and prevention of the disease. 【Method】 A model of avian salmonellosis was established by infecting 14-day-old male Wenchang chickens with S. typhimurium suspension of 8×10⁹ CFU/mL by oral gavage，and a healthy control group and an inactivated bacterial control group were simultaneously established. Metabolite detection and analysis based on metabolomics was performed on the cecum contents of Wenchang chickens on the 8^th d after infection，and metabolites with significant differences were screened out，and the differential metabolites were analyzed by KEGG enrichment. 【Result】 A total of 577 metabolites were identified in cecum content samples of Wenchang chickens，and the number of metabolites identified in positive ion（ESI⁺）mode and negative ion（ESI^-）mode were 417 and 160 respectively. A total of 32 differential metabolites were screened from the 577 metabolites using P<0.05 and weight（VIP）>1 as the screening condition. Compared to the healthy control group，24 differential metabolites were present in the S. typhimurium infected group and 25 differential metabolites were present in the inactivated bacterial control group. In the group infected with S. typhimurium， 9 metabolites including arachidonic acid，3-（3-hydroxyphenyl）propionic acid，D-ribose，N6-acetyl-L-lysine，guanosine，catechol，progesterone，3-methyl-L-tyrosine and 4-hydroxystyrene exhibited significant increase（P<0.05，the same below），while 15 metabolites including L-threonine，xanthine，guanine，hypoxanthine，uracil and tyramine demonstrated significant decline. Arachidonic acid content increase was the most obvious，the its fold difference compared to the healthy control group was 8.60. KEGG pathway enrichment analysis revealed that 24 differential metabolites enriched in 20 pathways，including purine metabolism，ABC transport protein，pyrimidine metabolism and biosynthesis of unsaturated fatty acid. Of these，the purine metabolism and ABC transport protein pathways reached significant level of enrichment. 【Conclusion】 S. typhimurium infection can cause metabolic disorders in the body of Wenchang chickens. In particular，arachidonic acid and its metabolites in the contents of the cecum may be the key substances mediating avian salmonella enteritis. This can provide a perspective for th study of Salmonella pathogenesis.