Several co-products from rice processing can be used as animal feed. Brown rice is the whole rice grain that is left after the hull layer has been removed, leaving the germ, starchy endosperm, and bran. Rice bran is the outer brown layer of brown rice, which is removed to produce white rice. It is high in fiber, and also contains about 15% crude protein and 14 to 20% fat. Rice bran can be fed as full fat rice bran or defatted rice bran. Broken rice, or brewer's rice, consists of white rice grains that have been damaged in processing. It is high in starch and contains little fat, fiber, or protein (Table 1).
Non–starch polysaccharides (NSPs), primarily arabinoxylan and cellulose, comprise 20 to 25% of defatted rice bran. NSPs reduce nutrient absorption and energy digestibility. Addition of exogenous xylanase to wheat co-products, which also have high concentration of NSPs, may improve digestibility of energy, but there is limited information about the effects of adding exogenous xylanases to rice co-products. Therefore, an experiment was conducted to determine the effect on concentrations of digestible energy (DE) and metabolizable energy (ME) of adding exogenous xylanase to diets containing full fat rice bran (FFRB), defatted rice bran (DFRB), brown rice, or broken rice.