不同胎仔数对大绒鼠（Eothenomys miletus）持续能量摄入的影响

摘要

Females in mammals appeared to approach an upper limit to the rate of sustained energy intake /metabolic rate ( SusEI/MR) during lactation.However, different species of animals may respond differently to the sustainable limit .Here, the energy metabo-lism was measured during lactation in female Eothenomys miletus raising litters of natural size (Con), and females whose litter size was manipulated during early lactation to support fewer or more pups (minus pups, MP or plus pups, PP).E.miletus significantly de-creased their body mass and increased food intake from early to late lactation , and MP females had lower food intake than the control and PP females .Litter size of the PP group decreased significantly over the period of lactation , and pups were weaned at similar weight to that of the controls .MP females supported a significantly lower litter mass throughout lactation compared with the control and PP fe -males, but during late lactation the pups from the MP group were significantly heavier .Resting metabolic rate ( RMR) did not differ significantly between the three groups and the energy intake during peak lactation was 3.56, 3.36 and 3.64 RMR for the control, MP and PP females , respectively .All of the results suggested that female E.miletus reached a plateau in food intake at around 12 g/d dur-ing peak lactation , which might signify a limit of SusEI at 3.6 ×RMR.%哺乳动物的母体往往会在哺乳期达到持续能量摄入和代谢率比值（ sustained energy intake／metabolic rate ， SusEI／MR）的上限。不同的动物其上限值不同。研究了大绒鼠在不同胎仔数条件下（少胎仔数组、对照组和多胎仔数组）其能量代谢的变化。结果表明：3组动物从哺乳期开始到结束都降低了体重，增加了食物摄入。少胎仔数组的食物摄入低于对照组和多胎仔数组。多胎仔数组的胎仔数在哺乳期中显著降低，断奶时胎仔数和对照组差异不显著。少胎仔数组总胎仔重显著低于对照组和多胎仔数组，而平均胎仔重要高于其它两组。3组动物的静止代谢率差异不显著，MP组、Con组和PP组的EI／RMR分别为3．56、3．36和3．64。以上结果表明大绒鼠在不同胎仔数条件下其最大摄入量在12 g／day，SusEI／MR比值维持在3．6倍。