Tryptophan metabolism in animals important roles in nutrition and health

Abstract

L-Tryptophan is a nutritionally essential amino acid for monogastric animals and preweaning ruminants because it cannot be synthesized in the body. Besides serving as a building block for proteins, tryptophan is a critical nutrient for the functions of nervous and immune systems. Over the past decades, much attention has been directed to study the role of tryptophan as a limiting amino acid in mammalian and avian nutrition. However, emerging evidence from recent studies shows that tryptophan and its metabolites (e.g., serotonin (5-hydroxytryptamine, 5-HT) and melatonin)) can regulate feed intake, reproduction, immunity, neurological function, and anti-stress responses. Additionally, tryptophan may modulate gene expression and nutrient metabolism to impact whole-body homeostasis in organisms. Thus, adequate intake of this amino acid from the diet is crucial for growth, development, and health of animals and humans.

Identification and functional characterisation of 5-HT4 receptor in sea cucumber Apostichopus japonicus (Selenka)

“…It has been described by Dr Barnes as the happy hormone2, involved in natural reward-related physiology and behaviour3, from feeding to sexual activity. Serotonin is biochemically derived from tryptophan and has various functions in different phyla, including both vertebrates and invertebrates, and plays a modulatory role in numerous physiological processes such as feed intake, reproduction, immunity and stress responses456.…”

Tryptophan hydroxylase-1 regulates immune tolerance and inflammation

“…It was shown that these enzymatic activities could dampen T cell proliferation through nutrient deprivation (Cobbold et al, 2009). One of the many enzymes that were up-regulated was Tph-1 (tryptophan hydroxylase-1), a synthase which utilizes tryptophan as a substrate to produce serotonin and melatonin (Yao et al, 2011), and it was speculated that Tph-1 may precipitate the loss of tryptophan in the local microenvironment (Zelenika et al, 2001). In the present study, we sought to determine whether Tph-1, the isoform expressed in the periphery (Walther et al, 2003), could function as a regulator of immunity through the control of tryptophan metabolism and uncovered a novel and profound immunoregulatory function for this enzyme.…”

Roles of Dietary Amino Acids and Their Metabolites in Pathogenesis of Inflammatory Bowel Disease

“…Trp is an essential AA for human and animals and plays an important role in inflammatory regulation beyond building block for proteins synthesis [65]. The serious Trp concentration shows a highly inverse correlation with disease activity in IBD patients [66].…”