title: Age-related changes in gonadal and serotonergic axes of broiler breeder roosters.
abstract: Fertility of domestic roosters decreases at ≈ 50 wk of age. In a previous study on aging white leghorn roosters, low fertility was accompanied by low levels of both hypothalamic vasoactive intestinal peptide (VIP) and pituitary prolactin (PRL) mRNA expression; however, their role in aging broiler breeder rooster reproduction is still unclear. In this study we compared reproductive activities of young (35-wk-old) and aging (73-wk-old) broiler breeder roosters. Weekly semen volume; concentration and ejaculation grade; and concentrations of plasma testosterone, estradiol, and PRL were examined. Every other week, 10 roosters from each group were euthanized, their testes weighed, and hypothalamus and pituitary removed to determine mRNA expression of hypothalamic GnRH-I, pituitary FSH, pituitary LH, hypothalamic VIP, and pituitary PRL. Aging roosters had significantly lower testis weight and semen volume, sperm concentration, ejaculation grade and plasma testosterone and low hypothalamic GnRH-I, pituitary FSH, and pituitary LH mRNA expression than young roosters (P ≤ 0.05). Aging roosters had higher concentrations of plasma estradiol and PRL and higher hypothalamic VIP and pituitary PRL mRNA expression than young roosters (P ≤ 0.05). We suggest that PRL, which is known to inhibit the gonadal axis, and its releasing factor, VIP, play an important role in the reproductive failure associated with age in broiler breeder roosters.
authors: Department of Animal Science, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel. natalieavital@yahoo.com
authors: N
authors: N
authors: Avital-Cohen
authors: R
authors: R
authors: Heiblum
authors: N
authors: N
authors: Argov-Argaman
authors: A
authors: A
authors: Rosenstrauch
authors: Y
authors: Y
authors: Chaiseha
authors: N
authors: N
authors: Mobarkey
authors: I
authors: I
authors: Rozenboim
mesh_terms: D000367:Age Factors; D000818:Animals; D002645:Chickens / Q000097:blood / Q000502:physiology*; D004958:Estradiol / Q000097:blood; D005640:Follicle Stimulating Hormone / Q000096:biosynthesis / Q000235:genetics; D007987:Gonadotropin-Releasing Hormone / Q000096:biosynthesis / Q000097:blood / Q000235:genetics; D007031:Hypothalamus / Q000378:metabolism / Q000502:physiology*; D007986:Luteinizing Hormone / Q000096:biosynthesis / Q000097:blood / Q000235:genetics; D008297:Male; D010902:Pituitary Gland / Q000378:metabolism / Q000502:physiology*; D011388:Prolactin / Q000097:blood*; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D012098:Reproduction / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D012661:Semen / Q000502:physiology; D059326:Serotonergic Neurons / Q000502:physiology; D013737:Testis / Q000033:anatomy & histology / Q000502:physiology; D013739:Testosterone / Q000097:blood; D014660:Vasoactive Intestinal Peptide / Q000096:biosynthesis / Q000097:blood* / Q000235:genetics
chemical_list: D012333:RNA, Messenger; D007987:Gonadotropin-Releasing Hormone; D014660:Vasoactive Intestinal Peptide; D013739:Testosterone; D004958:Estradiol; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone