title: Hormonal and metabolic adaptation to fasting: effects on the hypothalamic-pituitary-ovarian axis and reproductive performance of rabbit does.
abstract: To assess the impact of acute caloric shortage on reproduction, rabbit does were either fed ad libitum (control, AL), or fasted for 24 (STF) or 48 h (LTF) before induction of ovulation with GnRH injection. Blood samples were collected during the last 3 h of fasting, and the following 4 h after GnRH injection, when feed was provided again, to measure plasma concentrations of LH, estradiol-17beta, leptin, insulin, T3, corticosterone, glucose, and NEFA. Before re-feeding, plasma leptin, insulin, and T3 concentrations were lower (P < or = 0.01) in both fasted groups than in controls, but then gradually increased following realimentation to match those of controls. During fasting, corticosterone levels were higher (P < or = 0.01) in LTF than in STF and AL does, but decreased to control values soon after realimentation. During fasting, plasma glucose concentrations did not differ among groups, but upon re-feeding they markedly increased (P < or= 0.01) both in STF and LTF does. NEFA levels were also more elevated (P < or = 0.01) in fasted rabbits than in controls, and rapidly decreased (P < or = 0.01) after re-feeding. Following GnRH injection, LH peak was lower (P < or = 0.01) in LTF than in AL and STF does. Estradiol-17beta showed higher pulse frequency and amplitude in AL than in STF and LTF does. Compared to controls, receptivity rate of STF and LTF artificially inseminated does declined respectively by -20.5% (P < or = 0.05) and -22.7%, and fertility rate by -23.9% (P < or = 0.05) and 21.4%, but no difference was found in ovulation rate. In summary, nutritional status of does, as modified by fasting, greatly influenced fertility, metabolic and reproductive hormones.
authors.affiliation: Dipartimento di Scienze Biopatologiche Veterinarie ed Igiene delle Produzioni Animali e Alimentari, Sezione di Fisiologia, Laboratorio di Biotecnologie, Università degli Studi di Perugia, via S. Costanzo 4, 06126 Perugia, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Brecchia
authors.forename: Adriana
authors.initials: A
authors.lastname: Bonanno
authors.forename: Giovanna
authors.initials: G
authors.lastname: Galeati
authors.forename: Claudia
authors.initials: C
authors.lastname: Federici
authors.forename: Margherita
authors.initials: M
authors.lastname: Maranesi
authors.forename: Anna
authors.initials: A
authors.lastname: Gobbetti
authors.forename: Massimo
authors.initials: M
authors.lastname: Zerani
authors.forename: Cristiano
authors.initials: C
authors.lastname: Boiti
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003345:Corticosterone / Q000097:blood; D004958:Estradiol / Q000097:blood; D005215:Fasting / Q000097:blood / Q000502:physiology*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D006728:Hormones / Q000097:blood*; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000097:blood; D007986:Luteinizing Hormone / Q000097:blood; D010053:Ovary / Q000502:physiology*; D010062:Ovulation Induction / Q000662:veterinary; D010913:Pituitary-Adrenal System / Q000502:physiology*; D011247:Pregnancy; D011817:Rabbits; D011897:Random Allocation; D012098:Reproduction / Q000502:physiology*; D014284:Triiodothyronine / Q000097:blood
chemical_list: D001786:Blood Glucose; D006728:Hormones; D007328:Insulin; D020738:Leptin; D014284:Triiodothyronine; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D007986:Luteinizing Hormone; D003345:Corticosterone