title: Neuropeptide Y effect on food intake in broiler and layer chicks.
abstract: Broiler chicks eat more food than layer chicks. In this study, we examined the involvement of orexigenic peptide neuropeptide Y (NPY) in the difference in food intake between broiler and layer chicks (Gallus gallus). First, we compared the hypothalamic mRNA levels of NPY and its receptors (Y1 and Y5 receptors) between these strains at 1, 2, 4, and 8 days of age. Daily food intake was significantly higher in broiler chicks than layer chicks after 2 days of age. However, the hypothalamic NPY mRNA level was significantly lower in broiler chicks than layer chicks except at 8 days of age. In addition, the mRNA levels of NPY receptors were also significantly lower in broiler chicks than layer chicks at 2 and 4 days of age (Y1 receptor) or 2 days of age (Y5 receptor). These results suggest that the differences in the expressions of hypothalamic NPY and its receptors do not cause the increase in food intake in broiler chicks. To compare the orexigenic effect of NPY between broiler and layer chicks, we next examined the effects of central administration of NPY on food intake in these strains. In both strains, central administration of NPY significantly increased food intake at 2, 4 and 8 days of age. All our findings demonstrated that the increase in food intake in broiler chicks is not accompanied with the over-expression of NPY or its receptor.
authors.affiliation: Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Kobe, Japan.
authors.forename: Takaoki
authors.initials: T
authors.lastname: Saneyasu
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Honda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kamisoyama
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ikura
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nakayama
authors.forename: Shin
authors.initials: S
authors.lastname: Hasegawa
mesh_terms: D000818:Animals; D001066:Appetite / Q000187:drug effects / Q000502:physiology*; D002645:Chickens / Q000502:physiology*; D004435:Eating / Q000187:drug effects / Q000502:physiology*; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology*; D005260:Female; D007031:Hypothalamus / Q000378:metabolism / Q000502:physiology; D007276:Injections, Intraventricular; D008297:Male; D009478:Neuropeptide Y / Q000008:administration & dosage / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D017476:Receptors, Neuropeptide Y / Q000378:metabolism
chemical_list: D009478:Neuropeptide Y; D012333:RNA, Messenger; D017476:Receptors, Neuropeptide Y; C097212:neuropeptide Y-Y1 receptor; C100568:neuropeptide Y5 receptor