Increased dietary intake of tyrosine upregulates melanin deposition in the hair of adult black-coated dogs

作     者：Adrian Watson Jamie Wayman Russell Kelley AlexANDre Feugier Vincent Biourge 

作者机构：Royal Canin Research Centre30470 AimarguesFrance Royal Canin Pet Health Nutrition CenterLewisburgOH 45338USA 

出 版 物：《Animal Nutrition》 (动物营养（英文版）)

年 卷 期：2018年第4卷第4期

页      面：422-428页

核心收录：

学科分类：0710[理学-生物学] 0905[农学-畜牧学] 09[农学] 0906[农学-兽医学] 

主　　题：Canine Phenylalanine Amino acids Hair colour Eumelanin Pheomelanin 

摘      要：The principle determinant of melanin derived hair colour and patterning in mammals is genetic, but environmental factors are now thought to play a role. It has been shown that the concentration of melanins in cat hair is influenced by the amino acid composition of their diets. Also, puppies were found to require tyrosine(Tyr) intake significantly greater than that recommended for normal growth and development in order to optimize melanin expression in their coats. Much of the work to date has been conducted in growing animals. Less is known about the relationship between nutrition and hair melanin deposition in healthy adult animals. In this study, we fed 2 groups of adult black Labrador retrievers(12 dogs/group) different concentrations of Phe + Tyr(5.6 vs. 3.5 g/Mcal) for 24 weeks and used spectrophotometric measurements every 8 weeks to detect any associated changes in the dogs hair colour.The higher intake dogs showed reduced dilution of their black coat pigment compared with the lower intake dogs. Specifically, following 16 weeks at the higher intake, the dogs showed less yellow pigmentation to their coats(P = 0.0032), and after 24 weeks at the higher intake, the dogs showed less red(P 0.0001) and yellow(P 0.0001), as well as greater overall dark pigmentation(P 0.0001). In conclusion, we have demonstrated for the first time that colour expression in the hair-coat of adult dogs is dependent on dietary intake of Tyr, and that the requirement appears to be in excess of the minimum level recommended to maintain health.