The effect of different combinations of antibiotic cocktails on mice and selection of animal models for further microbiota research.

The gut microbiota is closely related to host health and disease. However, there are no suitable animal models available at present for exploring its functions. We analyzed the effect of 3 different antibiotic cocktails (ABx) via two administration routes on the composition of murine gut microbiota, as well as on the general physiological and metabolic indices. High-throughput 16S rRNA sequencing showed that ABx treatment altered the gut microbiota community structure, and also caused low-degree inflammation in the colon. In addition, ad libitum administration of antibiotics depleted the gut microbiota more effectively compared to direct oral gavage, especially with 3ABx. The ABx treatment also had a significant impact on renal and liver functions, as indicated by the altered serum levels of creatinine, urea, total triglycerides, and total cholesterol. Finally, Spearman's correlation analysis showed that the predominant bacterial genera resulting from ABx intervention, including Lactobacillus, Roseburia, and Candidatus-Saccharimonas, were negatively correlated with renal function indices. Taken together, different antibiotic combinations and interventions deplete the gut microbiota and induce physiological changes in the host. Our findings provide the basis for developing an adaptive animal model for studying gut microbiota. KEY POINTS: • Ad libitum administration of 3ABx can effectively deplete intestinal microbiota. • ABx treatment may have slight effect on renal and liver function. • The levels of urea and creatinine correlated with the growth of Roseburia.