Phillip S. Miller, Austin J. Lewis, and Cynthia K. Wolverton
Summary and Implications
An experiment with growing-finishing pigs was conducted to evaluate the effects of a corn-soybean meal diet supplemented with crystalline amino acids in an ideal pattern for the first four limiting amino acids (lysine, tryptophan, threonine, and methionine) on growth performance, plasma urea concentration, and carcass characteristics in barrows and gilts. Barrows were pair-fed to gilts within the same dietary treatment. For the entire growing-finishing period, there was a diet x sex interaction for daily gain and feed efficiency. Barrows and gilts consuming a corn-soybean meal diet performed similarly; however, barrows receiving diets formulated on an ideal protein basis had a 10% lower daily gain and a 4% lower daily feed intake than gilts. Barrows and gilts receiving the ideal protein diet gained weight more slowly and consumed less feed during the growing-finishing period than did pigs receiving the intact corn-soybean diet. Diet did not affect the percent lean in the carcass. Plasma urea concentrations showed that nitrogen was conserved in pigs consuming the ideal protein vs intact corn-soybean meal diet. Differences in plasma urea concentration were not observed between barrows and gilts within either treatment. These results indicate there is no advantage in terms of daily gain and feed efficiency of providing growing-finishing pigs an ideal protein diet.