An experiment was conducted to investigate the effect of arginine on feed intake regulation.One hundred and twenty six 1-day-old male White Pekin ducks(Anas platyrhynchos domestica)were randomly were allotted to one of two dietary treatments,birds were fed diets containing 0.71%(deficient)or 1.27%(sufficient)arginine for 3 weeks.At 21 days of age,feed intake were determined and hypothalamic protein profiles were analysed using isobaric tags for relative and absolute quantization technique.The birds fed with arginine-deficient diet had a lower final live body weight and cumulative feed intake(P<0.01)than those fed with arginine-sufficient diet.A total of 16 proteins were identified in hypothalamus with > 1.5-fold expressional changes between arginine deficient and sufficient dietary treatments.Nine of these proteins were up-regulated and 7 of them were down-regulated.The identified proteins could be regrouped into 6 categories: protein processing,carbohydrate metabolism and energy production,transporter,cytoskeleton,immunity and neuronal development.Dietary arginine deficiency decreased expression of proteins involved in energy production(glycine amidinotransferase,aldolase B fructose-bisphosphate,aconitase,Transaldolase,6-phosphofructokinase type C-like)and oxygen transportation(hemoglobin subunit alpha expression).The proteomic alterations described here provides valuable insights into the interactions of arginine with appetite.