Disclosed is a method of preparing a feed material, the method comprising: changing the molecular structure of polysaccharides of a biomass comprising polysaccharides in the form of cellulose, hemicellulose, or starch by exposing the biomass to an electron beam from an electron beam irradiation device having a power of at least 5 kW to produce a feed material having a nutrient availability greater than the nutrient availability of the biomass.
