Abstract
Six 28-day experiments involving 354 pigs were conducted to compare the nutritional value of several varieties of opaque-2 corn analyzing from 0.37 to 0.45% lysine and normal corn analyzing 0.25% lysine in diets supplemented with various levels of soybean meal. Averaged over all levels of soybean meal, pigs fed opaque-2 corn gained faster and required less feed per unit of gain than those fed normal corn. Opaque-2 corn analyzing 0.42% lysine supported slightly faster and more efficient gains than opaque-2 corn analyzing 0.37% lysine, but the differences were not statistically significant. Increasing the level of soybean meal from 0 to 20% in the diet resulted in quadratic improvements in gain and feed/gain responses. Improvement in performance was more pronounced when soybean meal was added to normal corn than when added to opaque-2 corn, resulting in a significant corn type x soybean meal level interaction for both gain and feed/gain. Improvements in gain and feed/gain were linear when soybean was added to opaque-2 corn at levels of 10 to 20 %, but improvement in performance was quadratic when the soybean meal level added ranged from 10 to 30%. Performance appeared to maximize when 22 to 26% soybean meal was added to opaque-2 corn analyzing 0.45% lysine. Apparent digestibility of protein was significantly greater in diets containing normal corn. Digestibility of fat was lower in the opaque-2 than in the normal corn diets. Copyright © 1973. American Society of Animal Science . Copyright 1973 by American Society of Animal Science.