Santora J E, Palmquist D L, Roehrig K L
Department of Animal Sciences, Ohio Agricultural Research and Development Center, Wooster 44691, USA.
J Nutr. 2000 Feb;130(2):208-15. doi: 10.1093/jn/130.2.208.
Mice were fed pure trans11 octadecenoic acid (trans-vaccenic acid; TVA) to determine whether it is desaturated to cis9, trans11 octadecadienoic acid, a predominant isomer of conjugated linoleic acid (CLA). In a preliminary trial, 12% of the TVA consumed during a 2-wk feeding period was recovered in the carcass as CLA. As a proportion of TVA in the tissues available for bioconversion, 48.8% was desaturated. We tested whether desaturation could be modified by supplementing no modifier, 0.5% clofibric acid to stimulate desaturation, or increasing the polyunsaturated fatty acids (PUFA) (10% corn oil vs. 4% corn oil) to inhibit desaturation in diets with or without 1% TVA. These diets were fed to six groups of mice in a 3x2 factorial arrangement of treatments. Feeding 1% TVA with 10% corn oil decreased feed intake (2.70 vs. 3.73 g/d, SEM 0.23; P<0.05). Bioconversion of dietary TVA was 12.0, 7.5 and 5.1% for mice fed no modifier of desaturation, clofibrate and increased PUFA, respectively. Conversion based on TVA available for desaturation was 52.6, 55.5 and 37.0%, respectively. Thus, clofibrate did not increase bioconversion, but increasing PUFA decreased conversion by 30%. To test whether TVA decreases food intake directly or after conversion to CLA, four groups of mice were fed diets containing 1% stearic, TVA, elaidic or conjugated linoleic acid. Dietary CLA decreased food intake and body fat, but did not change body protein. CLA was found in the carcass only when TVA or CLA was fed. CLA was found in both triacylglycerol and phospholipids when CLA was fed, but only in triacylglycerol when TVA was fed, suggesting that bioconversion occurred in the adipose tissue. In three trials, conversion of dietary TVA to CLA was 11.4+/-1.25%; conversion of stored TVA was 50.8+/-1.91%. Similar bioconversion of TVA in humans would increase current estimates of CLA available for the general population by 6- to 10-fold.
给小鼠喂食纯反式11-十八碳烯酸（反式- vaccenic酸；TVA），以确定它是否会去饱和生成顺式9，反式11-十八碳二烯酸，即共轭亚油酸（CLA）的主要异构体。在一项初步试验中，在为期2周的喂食期内摄入的TVA中有12%在胴体中以CLA的形式回收。作为可用于生物转化的组织中TVA的比例，48.8%发生了去饱和。我们测试了去饱和是否可以通过补充无调节剂、0.5%的氯贝丁酯以刺激去饱和，或增加多不饱和脂肪酸（PUFA）（10%玉米油与4%玉米油）以抑制去饱和来改变，这些情况分别出现在含或不含1% TVA的日粮中。这些日粮以3×2析因处理安排喂给六组小鼠。给小鼠喂食1% TVA和10%玉米油会降低采食量（分别为2.70与3.73克/天，标准误0.23；P<0.05）。对于未添加去饱和调节剂、氯贝特和增加PUFA的小鼠，日粮TVA的生物转化率分别为12.0%、7.5%和5.1%。基于可用于去饱和的TVA的转化率分别为52.6%、55.5%和37.0%。因此，氯贝特并没有增加生物转化率，但增加PUFA使转化率降低了30%。为了测试TVA是直接降低采食量还是在转化为CLA后降低采食量，给四组小鼠喂食含1%硬脂酸、TVA、反油酸或共轭亚油酸的日粮。日粮CLA降低了采食量和体脂，但没有改变体蛋白。仅在喂食TVA或CLA时在胴体中发现了CLA。喂食CLA时在甘油三酯和磷脂中均发现了CLA，但喂食TVA时仅在甘油三酯中发现，这表明生物转化发生在脂肪组织中。在三项试验中，日粮TVA向CLA的转化率为11.4±1.25%；储存TVA的转化率为50.8±1.91%。人类中类似的TVA生物转化将使目前对普通人群可获得的CLA的估计增加6至10倍。
