Chin S F, Storkson J M, Liu W, Albright K J, Pariza M W
Department of Food Microbiology and Toxicology, University of Wisconsin-Madison 53706.
J Nutr. 1994 May;124(5):694-701. doi: 10.1093/jn/124.5.694.
Conjugated linoleic acid (CLA) is an anticarcinogen in several model animal systems. Conjugated linoleic acid occurs naturally in food and is present at higher concentrations in products from ruminant animals. Given that certain rumen microorganisms produce CLA from free linoleic acid, we studied the effect of feeding free or esterified linoleic acid on tissue CLA concentrations using conventional and germ-free rats. Conventional rats were fed a 5% (wt/wt) corn oil control diet alone or supplemented with 5% free linoleic acid or 8.63% corn oil (equivalent to 5% linoleic acid in triglyceride). Germ-free rats were fed autoclavable nonpurified diet alone or supplemented with 5% free linoleic acid. Analyses of CLA concentrations were performed on lipids extracted from liver, lung, kidney, skeletal muscle and abdominal adipose tissue, and on liver phospholipid and neutral lipid fractions. Tissue CLA concentrations were higher in conventional rats fed free linoleic acid (the major isomers were cis-9, trans-11 and trans-9, cis-11) than in control animals. Conjugated linoleic acid concentrations in free linoleic acid-fed rats were maximal at 4 wk, and levels were 5-10 times higher than those of controls. Elevated CLA concentrations were also observed in liver phospholipid and neutral lipid fractions. In contrast, CLA concentrations in the tissues of germ-free rats were not affected by diet. Feeding the corn oil-fortified diet to conventional rats did not increase CLA concentration in the tissues.(ABSTRACT TRUNCATED AT 250 WORDS)
共轭亚油酸（CLA）在多种动物模型系统中是一种抗癌物质。共轭亚油酸天然存在于食物中，在反刍动物产品中的浓度更高。鉴于某些瘤胃微生物可将游离亚油酸转化为CLA，我们使用普通大鼠和无菌大鼠研究了喂食游离或酯化亚油酸对组织CLA浓度的影响。普通大鼠单独喂食5%（重量/重量）玉米油对照饮食，或补充5%游离亚油酸或8.63%玉米油（相当于甘油三酯中5%的亚油酸）。无菌大鼠单独喂食可高压灭菌的非纯化饮食，或补充5%游离亚油酸。对从肝脏、肺、肾脏、骨骼肌和腹部脂肪组织中提取的脂质，以及肝脏磷脂和中性脂质部分进行CLA浓度分析。喂食游离亚油酸的普通大鼠（主要异构体为顺-9，反-11和反-9，顺-11）组织中的CLA浓度高于对照动物。喂食游离亚油酸的大鼠CLA浓度在4周时达到最高，比对照组高5至10倍。在肝脏磷脂和中性脂质部分也观察到CLA浓度升高。相比之下，无菌大鼠组织中的CLA浓度不受饮食影响。给普通大鼠喂食强化玉米油饮食并未增加组织中的CLA浓度。（摘要截短至250字）
