Corn
Corn is the most common cereal grain used in swine diets in the United States and many countries around the world. Corn grain contains relatively greater energy level than other cereal grains due to its high concentration of starch, oil, and low concentration of fiber. Corn is usually the standard by which other energy sources are evaluated.
The apparent total tract digestibility of starch is around 90-96% and total dietary fiber content is less than 10% in corn (Rojas and Stein, 2015). Crude protein content in corn is less than most other cereal grains (between 7-9% crude protein), but amino acid digestibility is relatively high (Cervantes-Pahm et al., 2014). Phosphorus content in corn is approximately 0.25%, but standardized total tract digestibility of phosphorus is only 25-30% because at least 2/3 of the phosphorus is bound to phytate. The addition of exogenous phytase is a common practice in corn-based diets to increase phosphorus digestibility to around 45-60% (Amanda and Stein, 2012).
Improvements in genetic selection and modification have resulted in new corn varieties with enhanced nutrient profiles for use in swine diets. These corn varieties generally have greater concentrations of energy and may have altered content or digestibility of nutrients such as lysine or phosphorus compared with traditional, yellow dent corn. Common corn varieties with altered composition include nutrient dense, high oil, high lysine, and low phytate corn. The decision to use of a modified variety should take into consideration the energy content and nutrient profile compared to regular corn, as well as the opportunity to reduce the inclusion of fat, soybean meal, and inorganic phosphorus in the diet.