Carbohydrates normally serve as the most important source of bodily energy. Digestible carbohydrates are mostly sugars and starches. In animal feeds, corn is often used as an ingredient because it is rich in carbohydrates. Carbohydrates also include fiber, but its usefulness as an energy source depends upon the species consuming it. Ruminant animals have microorganisms to ferment fiber prior to absorption, and therefore these animals are able to utilize a majority of the energy generated by the breakdown of fiber.
For analytical purposes, the level of carbohydrates in a product is determined by analyzing for moisture, fat, protein, crude fiber and ash, then assuming that the carbohydrates are left over. This portion is called the nitrogen-free extract, or NFE. More precise analysis is difficult because there are so many different compounds that make up the carbohydrate category. The product fact sheets for the LabDiet® products include a break-out of some carbohydrate sources. The levels of starch and four of the sugars (sucrose, glucose, fructose and lactose) are provided.
Typically, the sources of carbohydrates in purified diets are sucrose (“table sugar,” a simple carbohydrate metabolized quickly), dextrin (a hydrolyzed starch product that provides simple and complex carbohydrates), or starch (“cornstarch,” a complex carbohydrate metabolized more slowly).