Apparent ileal digestibility of amino acids and the digestible and metabolizable energy content of high-oil corn varieties and its effects on growth performance of pigs

Abstract

Two experiments were conducted to compare the nutritional value of normal and high-oil corn for pigs. The normal corn and the two varieties (high-oil corns A and B) of high-oil corn contained 4.41, 7.35 and 8.86% ether extract, on DM basis, respectively. In experiment 1, six non-littermate crossbred barrows (37.8 ± 1.3 kg BW) were fitted with ileal T-cannulas and used in a double replicated Latin Square digestion trial. Three diets were formulated containing 96.6% of one of the three varieties of corn as the only protein source. Chromic oxide (0.4%) was added as a digestibility marker. Additional vitamins and minerals were added to meet requirements. The digestible energy concentrations for normal corn and high-oil corn A and B were 16.53, 16.99 and 17.07 MJ/kg while the metabolizable energy values were 15.82, 16.32 and 16.36 MJ/kg, on DM basis, respectively. The ileal amino acid digestibility of high-oil corn was generally higher than that of normal corn with significant differences being observed for the essential amino acids isoleucine and phenylalanine. In experiment 2, 96 pigs (8.01 ± 0.14 kg BW) were used to evaluate four diets in a 2 × 2 factorial design conducted over a 35-day period. Corn variety (high-oil vs. normal corn) and nutrient density (high content of protein and ME vs. low content of protein and ME) were set as the two main effects. During the first 14 days, pigs fed high-oil corn diets consumed more feed and tended to get higher daily gain than pigs fed normal corn. Over the entire 35-day experiment, increasing dietary nutrient density increased daily gain and tended to increase feed conversion, while variety of corn had no significant effects on performance. Overall, the present results indicate that the energy concentration and ileal amino acid digestibility of high-oil corn varieties were equal or superior to those in normal corn and therefore they should be able to be effectively utilized in diets fed to swine.