**Abstract**

While fiber is not an indispensable nutrient for monogastric animals, it has benefits such as promoting gastrointestinal motility and production of short chain fatty acids through fermentation. *Miscanthus x giganteus* is a hybrid grass used as an ornamental plant, biomass for energy production, construction material, and as a cellulose source for paper production. More recently Miscanthus grass (dried ground *Miscanthus x giganteus*) was evaluated for its fiber composition and as a fiber source for poultry (broiler chicks) and pets (dogs and cats). As a fiber source, this ingredient is mostly composed of insoluble fiber (78.6%) with an appreciable amount of lignin (13.0%). When added at moderate levels to broiler chick feed (3% inclusion) Miscanthus grass improved dietary energy utilization. However, when fed to dogs at a 10% inclusion Miscanthus grass decreased dry matter, organic matter, and gross energy digestibility, and increased dietary protein digestibility compared to dogs fed diets containing similar concentrations of beet pulp. Comparable results were reported for cats. In addition, when Miscanthus grass was fed to cats to aid in hairball management, it decreased the total hair weight per dry fecal weight. When considering the effects Miscanthus grass has on extruded pet foods, it behaves in a similar manner to cellulose, decreasing radial expansion, and increasing energy to compress the kibbles, likely because of changes in kibble structure. To date, Miscanthus grass has not been evaluated in human foods and supplements though it may have applications similar to those identified for pets.

**Keywords:** *Miscanthus x giganteus*, fiber nutrition, insoluble fiber, pet nutrition, human nutrition, pet food processing, fiber profile
