Amino acid requirements for nursery pigs
The amino acid requirements of nursery pigs have increased significantly over time. As pigs have been growing faster with lower feed intake, the amino acid requirements as percentage of the diet have increased.
Current statistical modelling techniques have been applied to determine the dose-response to individual amino acids. Recently, the requirements of lysine (Graham et al., 2017; Nichols et al., 2018) and ratios for methionine and cysteine, threonine, tryptophan, isoleucine, valine, and histidine relative to lysine have been estimated for nursery pigs (Gonçalves et al., 2015; Jayaraman et al., 2015; Clark et al., 2017b,c; Kahindi et al., 2017; Cemin et al., 2018). By doing so, it is possible to determine the requirement to maximize growth performance and also predict the change in growth performance at a particular amino acid level. From a practical feeding standpoint, it is not always economical to feed diets at the amino acid levels to maximize growth performance. In many cases, it is more advantageous to feed diets with amino acid levels to achieve 95 to 99% of maximal growth performance than at levels to achieve 100% of maximal growth in the nursery (Table 1).