Increasing dietary methionine, threonine and tryptophan at weaning: effects on piglet health and performances in bioinsecure pig breeding conditions

Les Cahiers de l'IFIP, 8(1), 9-17
Recent research indicates that methionine, threonine and tryptophan have beneficial effects on digestive health, inflammatory response and antioxidant status in weaning-transition piglets. With that vision, we ran a trial designed to test a nursery diet feed fortified with methionine, threonine and tryptophan on piglets raised in very bioinsecure pig breeding conditions. Added dietary synthetic amino acids can lead to higher methionine-to-lysine, methionine + cysteine-to-lysine, threonine-to-lysine and tryptophan-to-lysine ratios than the ideal protein profile routinely recommended for this stage of growth. This amino acids supplement was only distributed during the first two weeks post-weaning corresponding to the prestarter period. The results of this trial do not point to beneficial effect of high supplementation during the weaning-transition period. There were no significant pro-test-diet differences in animal-factor performances, and feed conversion ratio was significantly lower with the control diet over the full course of the post-weaning period. However, plasma haptoglobin concentration measured after 7 days post-weaning was significantly lower with the test diet, i.e. just before the diarrhoeal episode, and performances at this stage were better under the test diet in number terms but were not statistically significantly different. The evidence suggests that any beneficial effect of diet type largely disappears when pig-flow conditions become bioinsecure, which above all argues for compliance with internal and external biosecurity and mitigation measures.