title: 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.
authors.affiliation: Hunan Engineering and Research Center of Animal and Poultry Science and Key Laboratory for Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, China 410125.
authors.forename: Kang
authors.initials: K
authors.lastname: Yao
authors.forename: Jun
authors.initials: J
authors.lastname: Fang
authors.forename: Yu-long
authors.initials: YL
authors.lastname: Yin
authors.forename: Ze-Meng
authors.initials: ZM
authors.lastname: Feng
authors.forename: Zhi-Ru
authors.initials: ZR
authors.lastname: Tang
authors.forename: Guoyao
authors.initials: G
authors.lastname: Wu
mesh_terms: D000824:Animal Nutritional Physiological Phenomena / Q000502:physiology*; D000818:Animals; D005786:Gene Expression Regulation / Q000502:physiology*; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008550:Melatonin / Q000378:metabolism; D009420:Nervous System / Q000378:metabolism*; D009525:Niacin / Q000378:metabolism; D009751:Nutritional Requirements; D012701:Serotonin / Q000378:metabolism; D014364:Tryptophan / Q000008:administration & dosage / Q000276:immunology* / Q000378:metabolism*
chemical_list: D009525:Niacin; D012701:Serotonin; D014364:Tryptophan; D008550:Melatonin