Effect of Fertilizer on the Protein and Amino Acid Content of Yellow Corn and Implications for Feed Formulation

Analysis of samples of corn grain collected in the state of Rio Grande do Sul, Brazil, showed that fertilization with N, P, and K resulted in increases in crude protein content of corn. Among four pairs of samples, produced with and without fertilizer, the sulfur-containing amino acids and tryptophan were increased by a smaller factor than was total protein. In three of four comparisons, lysine was increased by a greater factor than was protein. In all comparisons, histidine and leucine were increased by a factor equal to or greater than that for protein. For the other amino acids, the relation of the increase to the increase in protein was not consistent. Chick mash formulas were calculated using analyses of high and low protein corn samples. Use of high protein corn resulted in a 12% reduction in the level of soybean meal and did not affect, either favorably or unfavorably, the need for amino acid supplementation.