Hormonal and metabolic adaptation to fasting: effects on the hypothalamic-pituitary-ovarian axis and reproductive performance of rabbit does.
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.
Brecchia
Gabriele
G
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.
Bonanno
Adriana
A
Galeati
Giovanna
G
Federici
Claudia
C
Maranesi
Margherita
M
Gobbetti
Anna
A
Zerani
Massimo
M
Boiti
Cristiano
C
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
D001786:Blood Glucose; D006728:Hormones; D007328:Insulin; D020738:Leptin; D014284:Triiodothyronine; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D007986:Luteinizing Hormone; D003345:Corticosterone