Chapter 24 final.pages

Plant carbohydrates can be classified into three categories: 1) simple sugars and their conjugates (glucose, fructose, etc.); 2) storage reserve compounds (starch); and 3) structural carbohydrates (cellulose, hemicellulose, etc.). Simple sugars and storage compounds are primarily digested in the upper gastrointestinal tract, although not completely, while structural carbohydrates are only partially degraded by the microflora in the cecum and large intestine (Slominski, 1991). Because most of the starch is removed from corn during ethanol production, the resultant co-product, dried distillers grains with solubles (DDGS), contains concentrated levels of protein, minerals, and fiber (Spiehs et al., 2002; Pedersen et al., 2007; Anderson, 2009). With pigs’ ability to utilize moderate, but not high levels of fiber in the nursery (Whitney and Shurson, 2004; Weber et al., 2008) and finisher (Whitney et al., 2006) period, there is a need to increase the ability of the pig to utilize the energy associated with the structural carbohydrates contained in corn-derived co-products (Muley et al., 2007). With the large amount of corn being utilized for ethanol production in the U.S., the amount of high fiber corn co-products available for animal feeds continues to increase. In order to minimize the cost associated with dietary energy and amino acids, it is essential that we develop and evaluate technologies that increase digestibility of energy and other nutrients. Use of exogenous enzymes is one of these technologies that offer promise for improving the nutritional value of high fiber corn co-products, particularly DDGS.