Rice bran is an atypical ingredient: it has excellent nutritive value, but it is undervalued by most nutritionists and the commodities market.
It all starts with rice grain as it arrives from the field. The rice we grow and the rice we humans eat do not look the same. Field rice comes with a tightly attached outer husk or hull, very much like barley and oats. Removing the hulls is the first step in the rice milling industry. Unlike other similar cereals, rice has hulls extremely rich in silica (silicon dioxide), better known as quartz or sand. As such, rice hulls are immensely abrasive not only on the feed mill machinery, but also inside the animal.