繁殖经历对黑线仓鼠哺乳期能量收支的影响

为探讨繁殖经历与哺乳期最大持续能量收支的关系,对连续4 次繁殖的黑线仓鼠哺乳期的能量收支情况进行了测定。结果显示:1)不同繁殖组哺乳高峰期的摄食量、泌乳能量支出(MEO)、胎仔数和胎仔重差异不显著,静止代谢率(RMR)、非颤抖性产热(NST)、褐色脂肪组织(BAT)线粒体细胞色素c 氧化酶(COX)活性、血清甲状腺激素(T3 、T4 )和催乳素水平也无明显变化;2)摄食量与MEO、胎仔重和RMR 呈显著正相关。结果表明,不同繁殖经历的黑线仓鼠主要通过降低产热和增加能量摄入来满足哺乳高峰期的能量需求;哺乳期最大持续代谢率(SusMR)可能受乳腺组织泌乳能力的限制,与“外周限制假说” 的预测一致,不支持“中心限制假说”;SusMR 限制因素和哺乳期能量收支策略可能与繁殖经历无关。

Effect of reproductive experiences on energy budget during lactation in the striped hamster(Cricetulus barabensis)

Energy budgets during peak lactation were measured in striped hamsters throughout the first,second,third and fourth lactation events.The present study showed that 1) asymptotic food intake,milk energy output(MEO),litter size and mass,resting metabolic rate(RMR),nonshivering thermogenesis(NST),mitochondria cytochrome c oxydase(COX) activity of brown adipose tissue(BAT),serum T3,T4 and prolactin levels did not differ between the four bouts of lactation;2) the asymptotic food intake was significantly correlated with MEO,litter mass and RMR.This suggests that striped hamsters with different reproductive experiences are able to compensate for the high energy demands during peak lactation by increasing energy intake and decreasing energy expenditure associated with thermogenesis.Sustained metabolic rate(SusMR) during peak lactation may be limited by the capacity to produce milk,which is more likely consistent with the prediction of the "peripheral limitation hypothesis" rather than the "central limitation hypothesis".Limits to SusMR may be independent of the reproductive experiences.