NSP enzymes: Interaction with each other and dietary factors

Recent interest in renewable energy production has exponentially increased the utilization of ethanol, a biofuel produced largely from corn in the United States. Increased production of ethanol has redistributed corn from livestock production to ethanol production. In 2002, 11% of the US corn crop was used in ethanol production; with the increase in production as much as 30% of US corn was being used for ethanol production in 2008 (Donohue and Cunningham, 2009). This reallocation has directly resulted in large increases in diet cost in animal production. Between the years of 2006 and 2008, feed costs in the poultry industry increased as much as $9.36 billion dollars in the United States alone (Donohue and Cunningham, 2009). The cost of broiler feed in the United States more than doubled from $120 to $250 per ton during this period (Donohue and Cunningham, 2009). The increase in feed cost can be directly attributed to the reallocation of corn use for ethanol production, which has directed corn away from agriculture feed use and increased the demand and value of energy (Masey O’Neill et al., 2012). Other factors such as drought in the Midwest in recent years have also attributed to a steady increase in corn and all ingredient costs over the past several years. Elevated diet cost increases overall production costs, thus dietary inclusion of potentially less desirable ingredients has been one strategy use to reduce diet cost. Due to continued increase in ethanol production, distillers’ dried grains with solubles (DDGS) has become widely available as a result of the expansion of ethanol production (Loar et al., 2010). However, nutrient variability of DDGS associated with the ethanol production process can be a potentially limiting factor in feed formulation. Additionally, processes such as de-oiling can reduce the nutritive value of DDGS to poultry. Other ingredients that are currently being selected for use in poultry diets include wheat and sorghum. Maximizing nutrient utilization from ingredients is a necessity as improving nutrient utilization will reduced required feed for production and reduce nutrient excretion onto the litter. Therefore, the dilemma for poultry nutritionists is this; reduce diet cost with alternative ingredients with lower nutrient value which may have a negative effect on nutrient utilization. Ingredients that are typically classified as alternative ingredients or less desirable ingredients are associated with higher concentrations of non-starch polysaccharides (NSP). Non-starch polysaccharides, the major components of dietary fiber in commonly used ingredients in poultry diets, comprise cellulose and non-cellulosic polysaccharides.