Effect of dry, high-moisture and reconstituted normal and high-lysine corn diets and particle size on energy and nitrogen metabolism in growing swine

Two metabolism studies were conducted with 24 (Exp. 1) and 36 (Exp. 2) crossbred barrows (initial weight 35 kg) to determine the effect of corn type--normal corn (NC) and high-lysine corn (HLC)--and storage method--dry (D), high-moisture (HM) and reconstituted (RC)--on energy and N digestibility. Diets fed in Exp. 1 were: 1, NC-soybean meal formulated at .78% lysine (dry matter basis); 2, HLC-soybean meal containing the same amount of corn as diet 1 (.87% lysine); 3, HLC-soybean meal with the same lysine level as diet 1. In Exp. 1, dry matter, energy and N digestibilities were not different between corn types or lysine levels (P greater than .16). These results indicate that energy and N digestibility of HLC in typical diets for growing swine are similar to those for NC diets when both are balanced on a lysine basis. Also, replacing NC with HLC on an equal-weight basis did not affect energy and N digestibility. In Exp. 2 six diets balanced on an isonitrogenous and dry-matter basis were tested. Normal corn and HLC diets, which had been stored by three different methods (D, HM and RC) were arranged in a 2 X 3 factorial plan. There were no differences between corn types in dry matter, energy and N digestibilities. The HM and RC treatments had larger particle sizes than the dry corn diets. For diets balanced on an isonitrogenous basis, dry corn storage improved energy digestibility (P less than .10). Reconstitution appeared to improve energy balance and N digestibility of HLC, while HM storage improved energy balance and N digestibility of NC.