Experiments were conducted to estimate the threonine requirement of pigs weighing 5 to 15 kg and to determine whether excess methionine increased the threonine requirement. Feeding .70% dietary threonine in Exp. 1 maximized (P less than .01) gain/feed and minimized (P less than .01) plasma urea N. Plasma threonine was increased (P less than .01) by threonine supplementation and the rate of increase accelerated above .65% dietary threonine. Threonine supplementation did not affect plasma methionine, tryptophan and(or) lysine, but it increased leucine (P less than .01) and isoleucine (P less than .05). In Exp. 2, additions of .40% methionine and(or) .30% threonine to a 16% crude protein diet that had calculated concentrations of .57% sulfur amino acids and .68% threonine did not affect (P less than .10) pig performance or plasma urea N. In Exp. 3, a 15% crude protein diet that had calculated concentrations of .54% sulfur amino acids and .61% threonine was supplemented with .40% methionine and(or) .15% threonine. Amino acid additions did not affect performance of pigs, but pigs fed supplemental threonine had the least plasma urea N, indicating that .61% dietary threonine was marginally deficient for pigs weighing 5 to 15 kg.

No abstract

This reproduction was made from a copy of a document sent to us for microfilming. While the most advanced technology has been used to photograph and reproduce this document, the quality of the reproduction is heavily dependent upon the quality of the material submitted. The following explanation of techniques is provided to help clarify markings or notations which may appear on this reproduction.