Amino acid requirements of pigs. 3. Requirement for apparent digestible threonine of pigs in different stages of growth.

Abstract

Individual and group housed crossbred pigs 45 to 105 kg and 65 to 95 kg in experiments 1 and 2, respectively, were given basal diets with L-threonine 0.6, 1.2 and 1.8 g/kg. Positive and negative control diets contained total threonine 5.7 and 4.5 g/kg, respectively. To prevent other amino acids being limiting, the negative control diet was supplemented with lysine, methionine, tryptophan, isoleucine, histidine and valine. The positive control diet was supplemented with lysine and methionine. The requirement for total threonine of growing-finishing pigs for maximum growth performance was about 5.6 g/kg in a diet containing net energy 9.4 MJ/kg. This figure corresponds with about 4.7 g/kg apparent faecal digestible threonine and 4.3 apparent ileal digestible threonine. There was no difference between the growing and the finishing pigs. The requirement for ileal digestible threonine, relative to ileal digestible lysine requirement, was about 64%. It is concluded that dietary protein can be reduced by 2 percentage units without any adverse effect on growth performance, if limiting amino acids are sufficiently supplemented. (Abstract retrieved from CAB Abstracts by CABI’s permission)