Rising Russell, Lifshitz Fima
EMTAC Inc., 651 Vanderbilt St, #6J Brooklyn, NY 11218, USA.
Nutr Metab (Lond). 2006 Jan 31;3:11. doi: 10.1186/1743-7075-3-11.
Sub-optimally nourished rats show reduced growth, biochemical and physiological changes. However, no one has assessed metabolic rate adaptations in rats subjected to chronic suboptimal nutrition (CSN). In this study energy expenditure (EE; kcal/100 g body weight) and physical activity (PA; oscillations in weight/min/kg body weight) were assessed in rats subjected to three levels of CSN.
Body weight gain was diminished (76.7 +/- 12.0 and 61.6 +/- 11.0 g) in rats fed 70 and 60% of the ad-libitum fed controls which gained more weight (148.5 +/- 32.3 g). The rats fed 80% gained weight similarly to controls (136.3 +/- 10.5 g). Percent Fat-free body mass was reduced (143.8 +/- 8.7 and 142.0 +/- 7.6 g) in rats fed 70 and 60% of ad-libitum, but not in those fed 80% (200.8 +/- 17.5 g) as compared with controls (201.6 +/- 33.4 g). Body fat (g) decreased in rats fed 80% (19.7 +/- 5.3), 70% (15.3 +/- 3.5) and 60% (9.6 +/- 2.7) of ad-libitum in comparison to controls (26.0 +/- 6.7). EE and PA were also altered by CSN. The control rats increased their EE and PA during the dark periods by 1.4 +/- 0.8 and 1.7 +/- 1.1 respectively, as compared with light the period; whereas CSN rats fed 80 and 70% of ad-libitum energy intake had reduced EE and PA during the dark periods as compared with the light period EE(7.5 +/- 1.4 and 7.8 +/- 0.6 vs. 9.0 +/- 1.2 and 9.7 +/- 0.8; p < 0.05, respectively), PA(3.1 +/- 0.8 and 1.6 +/- 0.4 vs. 4.1 +/- 0.9 and 2.4 +/- 0.4; p < 0.05) and RQ (0.87 +/- 0.04 and 0.85 +/- 0.5; vs. 0.95 +/- 0.03 and 0.91 +/- 0.05 p < 0.05). In contrast, both light (7.1 +/- 1.4) and dark period (6.2 +/- 1.0) EE and PA (3.4 +/- 0.9 and 2.5 +/- 0.5 respectively) were reduced in rats fed 60% of ad-libitum energy intake.
CSN rats adapt to mild energy restriction by reducing body fat, EE and PA mainly during the dark period while growth proceeds and lean body mass is preserved. At higher levels of energy restrictions there is decreased growth, body fat and lean mass. Moreover EE and PA are also reduced during both light and dark periods.
营养状况欠佳的大鼠生长减缓，出现生化和生理变化。然而，尚无研究评估慢性营养摄入不足（CSN）大鼠的代谢率适应性变化。本研究对处于三种CSN水平的大鼠的能量消耗（EE；千卡/100克体重）和身体活动（PA；体重振荡次数/分钟/千克体重）进行了评估。
自由采食对照组大鼠体重增加（148.5±32.3克），而采食70%和60%自由采食量的大鼠体重增加减少（分别为76.7±12.0克和61.6±11.0克）。采食80%自由采食量的大鼠体重增加与对照组相似（136.3±10.5克）。与对照组（201.6±33.4克）相比，采食70%和60%自由采食量的大鼠无脂体重百分比降低（分别为143.8±8.7克和142.0±7.6克），而采食80%自由采食量的大鼠无脂体重（200.8±17.5克）未降低。与对照组（26.0±6.7克）相比，采食80%（19.7±5.3克）、7采食0%（15.3±3.5克）和采食60%（9.6±2.7克）自由采食量的大鼠体脂（克）减少。CSN也改变了EE和PA。与光照期相比，对照组大鼠在黑暗期EE和PA分别增加1.4±0.8和1.7±1.1；而采食80%和70%自由采食量的CSN大鼠在黑暗期的EE和PA低于光照期[EE（7.5±1.4和7.8±0.6对9.0±1.2和9.7±0.8；p<0.05），PA（3.1±0.8和1.6±0.4对4.1±0.9和2.4±0.4；p<0.05）]以及呼吸商（RQ）[（0.87±0.04和0.85±0.5对0.95±0.03和0.91±0.05；p<0.05）]。相比之下，采食60%自由采食量的大鼠在光照期（7.1±1.4）和黑暗期（6.作2±1.0）的EE和PA（分别为3.4±0.9和2.5±0.5）均降低。
CSN大鼠主要在黑暗期通过减少体脂、EE和PA来适应轻度能量限制，同时生长继续，瘦体重得以维持。在更高水平的能量限制下，生长、体脂和瘦体重均减少。此外，在光照期和黑暗期EE和PA也降低。
