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黑线仓鼠的BMR个体差异及其应对高脂食物的能量学对策

施璐璐 谭松 闻靖 赵志军   

  1. 温州大学生命与环境科学学院
  • 出版日期:2017-04-20 发布日期:2017-04-20

Individual differences in BMR and energetic strategies of striped hamsters in response to a high fat diet

SHI Lulu, TAN Song, WEN Jing, ZHAO Zhijun   

  1. College of Life and Environmental Science, Wenzhou University
  • Online:2017-04-20 Published:2017-04-20

摘要: 为探讨高脂食物对小型哺乳动物能量代谢的影响及其与基础代谢率(Basal metabolic rate, BMR)的关系,将成年雌性黑线仓鼠(Cricetulus barabensis)分为高、低BMR组,每组再随机分为低脂、高脂食物组,驯化6周后,测定体重、摄入能和代谢率,以及消化酶活力、褐色脂肪组织(Brown adipose tissue, BAT)和主要内脏器官与肌肉的细胞色素c氧化酶(Cytochrome c oxidase, COX)活性、解偶联蛋白(Uncoupling protein, UCP) mRNA表达等。结果显示,高脂食物对高、低BMR组动物体重均无显著影响。与低脂食物组相比,高脂食物组的摄食量、摄入能和消化能显著下降,小肠脂肪酶活力显著增强,消化率明显增加,但高、低BMR组的组间差异不显著。夜间代谢水平显著高于昼间,高脂食物使高BMR组的夜间代谢率显著升高。BAT、肌肉和内脏器官COX活性不受高脂食物的影响,高、低BMR组的组间差异也不显著。高脂食物组仅肝脏UCP2表达显著上调。结果表明,能量摄入和消化系统形态及功能的可塑性调节是黑线仓鼠应对高脂食物的主要策略;黑线仓鼠的代谢率具有显著的昼夜节律,既受高脂食物的影响,也与动物自身的BMR水平有关,但UCP表达具有组织特异性,这可能不是导致BMR个体差异的因素。

关键词: 基础代谢率, 消化酶, 能量代谢, 高脂食物, 黑线仓鼠, 解偶联蛋白

Abstract: The present study was aimed at examining the effect of a high-fat diet on energy metabolism in small mammals with different levels of basal metabolic rate (BMR). Adult female striped hamsters (Cricetulus barabensis) were assigned into high and low BMR groups according to BMR levels recorded during baseline measurements, and then each group was randomly sub-divided into either low or high-fat diet groups, which were fed low or high-fat diets for 6 weeks. Body mass, energy intake, metabolic rate, and digestive enzyme activities, as well as cytochrome c oxidase (COX) activity and mRNA expression of uncoupling protein (UCP) of brown adipose tissue (BAT), major visceral organs and muscle were measured. The results showed that body masses of either high or low BMR groups were not affected by a high-fat diet. The high-fat diet group significantly decreased food intake, gross energy intake and digestive energy intake, but increased lipase activity of small intestine and digestibility compared with the low-fat diet group, while the differences were not significant between high and low BMR groups. The metabolic rate during the night was significantly higher than that during the day. The metabolic rate of high-BMR animals during the night was higher in the high-fat diet group than that in low-fat diet group. The COX activity of BAT, muscle and visceral organs was not affected by a high-fat diet, and they were not different between high and low BMR groups. The high-fat diet induced a significant up-regulation of UCP2 expression in liver only. These findings suggest that plastic regulation of energy intake and the morphological and functional adjustments of the digestive system are employed by striped hamsters to cope with a high fat diet. A notable circadian rhythm of metabolic rate is observed in striped hamsters, which is associated the high-fat diet acclimation and is also related to their own BMR level. There is a tissue specific gene expression of UCP, and it may not be the factor resulting in individual differences in BMR.

Key words: Basal metabolic rate, Digestive enzymes, Energy metabolic rate, High-fat diet, Striped hamster, Uncoupling proteins