The increase in the prevalence of post weaning diarrhoea in pigs due to the progressive ban of antibiotic use has necessitated the use of alternative management and nutritional strategies (Le Bellego and Noblet, 2001). During immunological stress, amino acids are redistributed away from protein production towards tissues involved in inflammation and immune response. This can disturb normal body processes, which can in turn induce specific amino acid requirements. Threonine utilization by the gut is higher than that of any other amino acid because it is involved in the synthesis of intestinal mucin. Mucin plays a key role in the defence of the mucosa, however it is indigestible. Thus, when the positive effects of an antimicrobial growth promoter are removed, increased levels of dietary threonine may benefit piglets due to additional reserves of threonine being present to compensate for the portion of dietary threonine that becomes unavailable due to the increased synthesis of intestinal mucin. The objective of the experiment was to investigate the interaction between threonine level and avilamycin inclusion on piglet performance and diet digestibility post weaning.