Interpretive Summary: Tryptophan requirements in small, medium, and large breed adult dogs using the indicator amino acid oxidation technique.
By: Anne Wallace
Tryptophan (Trp) is an essential amino acid necessary for a variety of biological functions in dogs. Because dogs cannot produce Trp, they rely solely on their diet to meet daily requirements. Despite this fact, the minimum concentration of Trp required for adult dogs at maintenance lacks in the scientific literature. The current study published in the August 2019 issue of the Journal of Animal Science evaluated the Trp requirements of adult dogs at maintenance levels in three breeds (Miniature Dachshund, Beagles, and Labrador Retrievers).
A total of thirteen dogs were fed one of seven diets, each supplemented with a different concentration of crystalline Trp (0.092, 0.126, 0.148, 0.182, 0.216, 0.249, and 0.283% dry matter). The indicator amino acid oxidation (IAAO) technique was used to determine Trp requirements.
The results of this study noted that Trp needs were higher than current recommendations by the National Research Council (NRC) and Association of American Feed Control Officials (AAFCO) for adult dogs at maintenance. Additionally, Beagles had a significantly higher Trp requirement than Labrador Retrievers or Miniature Dachshunds.
Overall, more research into Trp requirements of adult dogs at maintenance is needed. There may additionally be differences in Trp requirements based on breed. More extensive studies looking at requirements in adult dogs at maintenance, including a wide variety of breeds is justified.
To view the article, visit theJournal of Animal Science.