title: Dietary macronutrient composition and central neuropeptide Y injection affect dietary preference and hypothalamic gene expression in chicks.
abstract: OBJECTIVE
  The objective of this study was to determine the influence of dietary macronutrient composition on central NPY's orexigenic effect in chicks.
  
  
  METHODS
  Day-of-hatch chicks were fed one of three diets (3000 kcal ME/kg) ad libitum from hatch: high carbohydrate (HC), high fat (HF; 30% ME derived from soybean oil), and high protein (HP; 25 vs. 22% CP). In Experiment 1, chicks received intracerebroventricular injections of 0 (vehicle), 0.2, or 2.0 nmol NPY on day 4 and food intake was recorded for 6 hours. In Experiment 2, chicks were given all three diets before and after injection. In Experiment 3, hypothalamus was collected at 1-hour post-injection for gene expression analysis.
  
  
  RESULTS
  The HC diet-fed chicks responded with a greater increase, while the chicks fed the HF diet had a lower threshold response in food intake to NPY. Neuropeptide Y dose-dependently increased food intake in chicks fed the HC and HP diets. Chicks administered 0.2 nmol NPY preferred the HC and HP diets over the HF diet. Relative quantities of hypothalamic NPYR1 and MC4R mRNA were reduced by NPY in chicks that consumed the HP and HC diets, respectively.
  
  
  CONCLUSIONS
  Consumption of the HC diet was associated with the most robust NPY-induced increase in food intake. Injection of NPY accentuated differences among dietary groups in hypothalamic gene expression of several appetite-associated factors, results suggesting that the NPY/agouti-related peptide and melanocortin pathways are associated with some of the diet- and NPY-induced differences observed in this study.
authors.affiliation: a Department of Animal and Poultry Sciences , Virginia Polytechnic Institute and State University , Blacksburg , VA , USA.
authors.forename: Betty R
authors.initials: BR
authors.lastname: McConn
authors.affiliation: a Department of Animal and Poultry Sciences , Virginia Polytechnic Institute and State University , Blacksburg , VA , USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Cline
authors.affiliation: a Department of Animal and Poultry Sciences , Virginia Polytechnic Institute and State University , Blacksburg , VA , USA.
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Gilbert
mesh_terms: D000818:Animals; D001066:Appetite / Q000187:drug effects; D002645:Chickens; D004032:Diet; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism; D057967:Infusions, Intraventricular; D009478:Neuropeptide Y / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D044105:Receptor, Melanocortin, Type 4 / Q000235:genetics / Q000378:metabolism; D017476:Receptors, Neuropeptide Y / Q000235:genetics / Q000378:metabolism
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins; D009478:Neuropeptide Y; D012333:RNA, Messenger; D044105:Receptor, Melanocortin, Type 4; D017476:Receptors, Neuropeptide Y; C097212:neuropeptide Y-Y1 receptor
keywords: Appetite; Chick; Diet; Dietary selection; Food intake regulation; Hypothalamus; Neuropeptide Y; mRNA