ABSTRACT: In order to study the metabolic adaptation in response to 48 h transient doe-litter separation (DLS) in youngrabbits (5 rabbits/d group) between postnatal 9 and 11 d, plasma concentrations of thyroid hormones T3 and T4, insulin,leptin, glucose, triglycerides (TG), and free fatty acids (FFA) were examined before (6-8 d), during (9-11 d), and afterseparation (12-16 d). T3 concentrations in newborn control rabbits gradually increased from 0.6 ng/mL at postnatal 6d to 1.0 ng/mL at postnatal 16 d, whereas those of T4 remained fairly constant (25 ng/mL) up to postnatal 14 d, whenT4 gradually declined to 8 ng/mL. T3 values of DLS newborn rabbits did not differ from those of controls at postnatal10 and 11 d, but were lower (P<0.05) at postnatal 12 d, while T4 concentrations in DLS animals increased, althoughnot signifi cantly, between postnatal 10 and 12 d compared to controls. Insulin concentrations in young control rabbitsranged between 0.6 and 1.0 mg/L in the early postnatal days, whereas those for leptin averaged 2-3 ng/mL. Insulinand leptin values in DLS newborn rabbits were lower (P<0.05) at postnatal 10 and 11 d, but thereafter rebounded tolevels close to those of controls. Glycaemia showed a comparable trend in both groups, ranging between 170 and190 mg/dL up to postnatal 14 d, but thereafter decreased (P<0.05) to values of 120-130 mg/dL independently oftreatment. Concentrations of TG varied greatly from day to day around a mean value of 300 mg/dL, whereas thoseof FFA remained at approximately the same steady-state levels from postnatal 6 to 16 d, averaging 0.8 mM withoutany signifi cant differences between groups. In conclusion, these fi ndings confi rm that newborn rabbits can cope withthe metabolic stress of starvation associated with DLS by lowering insulin and leptin concentrations while maintainingthose of thyroid hormones, an overall endocrine response which, together with temporary increase of glucorticoids,successfully maintains an adequate energy balance.
|Numero di pagine||8|
|Rivista||World Rabbit Science|
|Stato di pubblicazione||Published - 2010|
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