Prebiotics like oligofructose can not be digested by rodents or humans, but they are welcome treats for certain types of beneficial gut bacteria, like Bifidobacteria.
On a daily basis, most of us consume very small amounts of prebiotics (1 - 4g)-- mainly from foods like onion, leek, garlic, and dandelion greens (prebiotics are the non digestible oligofructose, inulin, galactooligosaccharides within these plants).