Net Protein Utilization and Amino Acid Deficiencies of Glandless Cottonseed Meal

MORE than twenty years ago Grau (1946) showed that lysine was the first and methionine the second limiting amino acid in the protein of regular cottonseed meal. Work recently reported from this laboratory (Fisher, 1965) indicated that in addition to lysine and methionine the amino acids leucine, threonine and isoleucine were also and equally limiting for optimum growth of chicks receiving regular cottonseed meal. Yet even when sufficient quantities of all five amino acids were added to cottonseed meal, its net protein utilization value (N.P.U.) was still much inferior to the value obtained for methionine-supplemented soybean meal (Fisher et al., 1962). In the present study, experiments were carried out with a glandless ariety of cottonseed meal produced in Texas, and processed at Texas A & M University. Under conditions similar to those previously employed with regular cottonseed meal, the glandless variety gave far superior N.P.U. values than the regular meal,…