The current invention relates to relates to methods of improving commensals in an animal by feeding the animal with a diet including quinoa grain. The quinoa grain is in an amount effective to increase parameters for commensals such as the percentage of lactobacillus in total microbiota, the percentage of bifidobacteria in total microbiota, the percentage of clostridium in total microbiota, and the firmicutes to bacteroidetes ratio. The current invention also relates to pet food compositions that include effective amount of quinoa grain to increase the commensals parameters. In addition, the methods of making such a food compositions are also disclosed.