Rat faecal microbiota composition associated with diet and phenotype

Abstract

Recently, it has been proposed that the development of obesity is influenced by the relative proportion of Bacteroidetes and Firmicutes, the two major phyla of bacteria found in the gut. We determined the fecal microbiota composition in diet induced obesity (DIO) and diet resistant (DR) selectively bred Sprague Dawley (SD) rats on different diets. When fed a 31% fat, high energy (HE) diet, DIO rats become obese whereas DR rats remain lean. However, when fed standard chow, both DIO and DR remain lean. Fecal samples were analyzed from four different groups of rats; 1) DIO rats fed HE diet (DIO‐HE; n=5); 2) DIO rats fed standard chow (DIO‐Chow; n=5); 3) Diet resistant rats fed HE diet (DR‐HE; n=5); and 4) Diet resistant rats fed standard chow (DR‐Chow; n=5). The composition of gut microbiota was determined using 16s rDNA sequencing. There was no significant difference in the Bacteroidetes (p = 0.06) and Firmicutes (p = 0.07) levels between the DIO (obese) and DR (lean) phenotype when fed the HE diet. However, there was a significant difference in the Bacteroidetes and Firmicutes levels between the DIO and DR phenotype when on the standard chow diet (p=0.05) despite both groups having similar body weights. These changes indicate that diet and phenotype affects the gut microbiota composition and suggests that intentional manipulation of community structure may be useful for regulating obese phenotype. (Hatch project # ILLU‐698‐339)