Hormonal and metabolic adaptation to fasting: effects on hypothalamus-pituitary-ovary axis and reproductive performance of rabbit does.
- Autori: BRECCHIA, G; BONANNO, A; GALEATI, G; FEDERICI, C; MARANESI, M; GOBBETTI, A; GERANI, M; BOITI, C
- Anno di pubblicazione: 2006
- Tipologia: Articolo in rivista
- Parole Chiave: Fasting; LH; Estradiol-17 ; Leptin; Insulin; T3; Corticosterone; Rabbit
- OA Link: http://hdl.handle.net/10447/30335
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 feedwas provided again, to measure plasma concentrations of LH, estradiol-17 , leptin, insulin, T3, corticosterone, glucose, and NEFA. Before re-feeding, plasma leptin, insulin, and T3 concentrations were lower (P≤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≤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≤0.01)both in STF and LTF does. NEFA levels were also more elevated (P≤0.01) in fasted rabbits than in controls, and rapidly decreased (P≤0.01) after re-feeding. Following GnRH injection, LH peak was lower (P≤0.01) in LTF than in AL and STF does. Estradiol-17 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≤0.05) and −22.7%, and fertility rate by −23.9% (P≤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.