Impact of Interplay between Obese Gut Microbiota and Diet in Developing Obesity in Synthetic Community Mice

This study aims at investigating the effects of cultured gut microbiota (GM) of obese human coupled high fat diet (HFD) or chow diet (CD) in development of obesity in mice. 20 stool samples were collected from obese patients and isolated bacteria were identified morphologically and biochemically. Identified isolates were mixed in equal proportions to synthesize obese GM. In vivo study was performed using obese GM combined with HFD/CD using mouse model for three months. Albino mice were treated with ampicillin from one week prior to birth until weaning of the pups at seven weeks of age and then inoculated with obese GM. Sixteen mice were divided into four groups: i.e. group 1 (G1) mice fed with CD, group 2 (G2) mice with HFD, group 3 (G3) mice with GM + HFD and group 4 (G4) mice with GM + CD. Mice from groups 3-4 were considered synthetic community (SC) mice due to transfer of synthesize human GM. 16S rRNA sequencing identified five abundant bacteria as Pseudomonas aeruginosa, Staphylococcus sp., Escherichia coli, Morganella morganii, and Klebsiella oxytoca (accession numbers: MZ150742-MZ150746). In vivo study indicated that GM combination with either HFD/CD caused significantly increased body weight in SC mice (BMI; Kg/m²) compared to HFD or CD fed mice groups. One way ANOVA revealed highly significant increase (p ≤ 0.001) in levels of total cholesterol (TC), triglycerides and low density lipoprotein (LDL) in GM coupled diet groups (G3-G4; SC mice) compared to significant increase in HFD group (G2) versus CD group (G1). Our study is first of its kind to report significant effects of using purified strains as obese GM plus diet (HFD/CD) in inducing obesity in SC mice and elevated serum liver parameters as metabolic indicators, hence providing strong evidence about significance of modified GM combination with HFD in developing obesity in SC mice.