Effects of Supplementary Amino Acids in an All-Corn Diet on the Growth and Metabolic Performance of Young Rats and Pigs

While there is presently an agreement on the status of lysine and tryptophan being closely first and second, or co-limiting, little beyond this is known. Which amino acids are the next limiting, and if they would give an important performance boost is unknown. The stage of the pig’s growth at which these factors are examined may also be important. Much of the work has been done with larger growing or finishing of pigs. It may be more advantageous to work with pigs that weigh from 10 to 35 kg compared to the 40 to 110 kg animal. It is at the lighter weight that pigs grow the fastest, relative to their body size, and have the highest feed efficiency. A larger pig has started to lay down more fat and the relative deposition of protein has slowed. A young pig deposits protein rapidly, and since this is the stage of life where the highest dietary concentrations of protein are required and fed, it may be better to examine improving the protein quality and thus increasing the level of total protein required. Therefore, the objective of the following experiments was to examine the effect of supplementing amino acids beyond lysine and tryptophan on performance and metabolic factors, in an attempt to identify the third and fourth limiting amino acids for young pigs fed an all-corn diet. Advisor: A. J. Lewis