Evaluation of curcumin and copper acetate against Salmonella Typhimurium infection, intestinal permeability, and cecal microbiota composition in broiler chickens

Abstract

Background: Interest in the use of natural feed additives as an alternative to antimicrobials in the poultry industry has increased in recent years because of the risk of bacterial resistance. One of the most studied groups are polyphenolic compounds, given their advantages over other types of additives and their easy potentiation of effects when complexes are formed with metal ions. Therefore, the objective of the present study was to evaluate the impact of dietary supplementation of copper acetate (CA), curcumin (CR), and their combination (CA-CR) against Salmonella Typhimurium colonization, intestinal permeability, and cecal microbiota composition in broiler chickens through a laboratory Salmonella infection model, indirect determination of intestinal integrity by measuring fitc-d in serum and microbiota analysis by DNA extraction.Results: The obtained results showed that in two independent studies, all experimental treatments were able to significantly reduce the S. Typhimurium colonization in cecal tonsils (CT, P< 0.0001) compared to the positive control (PC) group. However, CR and CA-CR were the most effective treatments in reducing S. Typhimurium counts. Furthermore, the serum fluorescein isothiocyanate dextran (FITC-d) concentration in chickens treated with CR was significantly lower when compared to PC (P= 0.0084), which is related to a decrease in intestinal permeability and therefore intestinal integrity. The effect of dietary treatments in reducing S. Typhimurium colonization was further supported by the Linear discriminant analysis effect size (LEfSe) analysis of microbiota data, where Salmonella was significantly enriched in PC group (LDA score > 2.0 and P<0.05). In addition, Coprobacillus, Eubacterium, and Clostridium were significantly higher in the PC group compared to other treatment groups. On the contrary, Fecalibacterium and Enterococcus in CR, unknown genus of Erysipelotrichaceae at CA-CR, and unknown genus of Lachnospiraceae at CA were significantly abundant respectively.Conclusions: CR treatment was the most effective treatment to reduce S. Typhimurium intestinal colonization and maintain better intestinal homeostasis which might be achieved through modulation of cecal microbiota.