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Effect of fur removal on energy budget in lactating KM mice supporting additional pups

ZHAO Zhijun   

  1. School of Agricultural Science,Liaocheng University ,Liaocheng 252059,China
  • Online:2010-05-27 Published:2010-03-02

剃毛和增加胎仔数对KM 小鼠哺乳期能量收支的影响

赵志军   

  1. 聊城大学农学院,聊城 252059

Abstract: The aim of this study was to understand the factors limiting maximum sustainable energy intake and metabolic
rate (SusEI/ MR)during lactation. Maternal body mass,food intake,litter size and litter mass throughout lactation and basal metabolic rate (BMR)and thermal conductance during late lactation were measured in dorsally shaved KM mice supporting additional pups. BMR within the thermal neural zone of this species was determined using a closed-circuit respirometer. The present results showed that there were no significant effects of litter size on the maternal body mass,food intake, thermal conductance,BMR and litter mass during lactation. Shaved mothers had 13. 8% higher asymptotic food intake (P< 0. 001),18.1% higher BMR (P < 0.01)and 30.8% higher thermal conductance (P < 0.01)than did non-shaved controls. However,fur-removal had no significant impact on maternal body mass,litter size and litter mass. Litter size was significantly positively correlated with litter mass,but negatively correlated with mean pup body mass at weaning. There were also positive correlations between BMR and maternal body mass and litter mass. It suggested that SusEI/MR during lactation was constrained in KM mice. Fur-removal significantly increased the capacity to dissipate heat,but had no effect on reproductive output. The current study provided support for the “peripheral limitation hypothesis”but argued against the “heat dissipation limitation hypothesis”.

Key words: Fur-removal, Litter mass, Litter size, KM mice, Reproduction, Thermal conductance

摘要: 为探讨最大持续能量收支限制的因素和生理机理,本文测定了增加胎仔数和背部剃毛的KM 小鼠的哺乳
期摄食量和繁殖输出。基础代谢率(BMR)以封闭式流体压力呼吸计测定。结果发现,增加胎仔数对哺乳期体
重、摄食量、热传导率、BMR 和胎仔重的影响不显著;与非剃毛对照组相比,剃毛使哺乳高峰期日平均摄食量
增加了13.8% (P<0.001)、BMR 增加了18.1% (P< 0.01)、热传导增加了30.8% (P< 0.01),但剃毛对体
重、胎仔数和胎仔重的影响不显著;胎仔数与断乳时胎仔重显著正相关,与幼体平均体重显著负相关。BMR 与
母体体重和胎仔重显著正相关。这些结果表明,KM 小鼠哺乳期能量收支受到了限制,剃毛显著增强了KM 小鼠
的散热能力,但未影响繁殖输出;支持“外周限制假说”,不符合“热耗散限制假说”。

关键词: 剃毛, 胎仔重, 胎仔数, KM 小鼠, 繁殖, 热传导