Abstract: Disclosed herein are methods of treating an edible fiber source to make an animal feed with increased digestible energy. An exemplary method includes hydrolyzing the edible fiber source with an inorganic fiber hydrolyzing agent in a twin screw mixer that shears the edible fiber to a size of between 0.5 to 25 mm. The hydrolysis in the mixer occurs at pressure of about 14 psig or higher with a temperature about 100° C. to 110° C. The inorganic hydrolysis liberates a first portion of soluble carbohydrates from the edible fiber source. The inorganically hydrolyzed material is also treated (before or after) with a fiber degrading enzyme to solubilize a second portion of carbohydrates. The dually hydrolyzed material is dried to form an animal feed or feed ingredient having a soluble and insoluble carbohydrate fraction with the amount of soluble carbohydrate being at least 45% wt/wt of the total carbohydrates obtained from the edible fiber source.