LYSINE, THREONINE, METHIONINE AND ISOLEUCINE SUPPLEMENTATION OF PEACE RIVER BARLEY FOR GROWING PIGS

Abstract

The supplementation of Peace River barley was investigated in both a growth trial and a metabolism trial. The control diet consisted essentially of barley and soybean meal and provided 15.8% crude protein containing 0.75% total lysine. In the other diets, barley, as the sole source of protein, was supplemented with L-lysine HCl to provide 0.75 and 0.90% total lysine, with the former level also tested with 0.05% added L-threonine, alone or with 0.10% DL-methionine or with 0.10% DL-methionine plus 0.10% L-isoleucine. The growth trial incorporated three replicates, each with three gilts and three barrows group-fed on each diet, whereas in the metabolism trial, six observations per diet were made. The control diet produced greater daily gain, better feed utilization and leaner carcasses than any of the amino acid-supplemented diets. Gilts, but not barrows, grew more rapidly with the increase in lysine content from 0.75 to 0.90%. Addition of 0.05% L-threonine to the 0.75% lysine diet to provide 0.29% total threonine significantly improved daily gain and feed efficiency. Addition of methionine either with or without isoleucine to this latter diet had no effect on growth or feed utilization, but slightly improved nitrogen retention. Although nitrogen retained (expressed as a percentage of nitrogen absorbed) for all diets containing threonine was greater than the value for the control diet, values for nitrogen digestion and total nitrogen retention were less than for the latter diet.