Kramer J K, Sehat N, Dugan M E, Mossoba M M, Yurawecz M P, Roach J A, Eulitz K, Aalhus J L, Schaefer A L, Ku Y
Southern Crop Protection, Food Research Center, Agriculture and Agri-Food Canada, Guelph, Ontario.
Lipids. 1998 Jun;33(6):549-58. doi: 10.1007/s11745-998-0239-1.
Pigs were fed a commercial conjugated linoleic acid (CLA) mixture, prepared by alkali isomerization of sunflower oil, at 2% of the basal diet, from 61.5 to 106 kg live weight, and were compared to pigs fed the same basal diet with 2% added sunflower oil. The total lipids from liver, heart, inner back fat, and omental fat of pigs fed the CLA diet were analyzed for the incorporation of CLA isomers into all the tissue lipid classes. A total of 10 lipid classes were isolated by three-directional thin-layer chromatography and analyzed by gas chromatography (GC) on long capillary columns and by silver-ion high-performance liquid chromatography (Ag+-HPLC); cholesterol was determined spectrophotometrically. Only trace amounts (<0.1%; by GC) of the 9,11-18:2 cis/trans and trans,trans isomers were observed in pigs fed the control diet. Ten and twelve CLA isomers in the diet and in pig tissue lipids were separated by GC and Ag+- HPLC, respectively. The relative concentration of all the CLA isomers in the different lipid classes ranged from 1 to 6% of the total fatty acids. The four major cis/trans isomers (18.9% 11 cis,13 trans-18:2; 26.3% 10 trans,12 cis-18:2; 20.4% 9 cis,11 trans-18:2; and 16.1% 8 trans, 10 cis-18:2) constituted 82% of the total CLA isomers in the dietary CLA mixture, and smaller amounts of the corresponding cis,cis (7.4%) and trans,trans (10.1%) isomers were present. The distribution of CLA isomers in inner back fat and in omental fat of the pigs was similar to that found in the diet. The liver triacylglycerols (TAG), free fatty acids (FFA), and cholesteryl esters showed a similar pattern to that found in the diet. The major liver phospholipids showed a marked increase of 9 cis,11 trans-18:2, ranging from 36 to 54%, compared to that present in the diet. However, liver diphosphatidylglycerol (DPG) showed a high incorporation of the 11 cis,13 trans-18:2 isomer (43%). All heart lipid classes, except TAG, showed a high content of 11 cis,13 trans-18:2, which was in marked contrast to results in the liver. The relative proportion of 11 cis,13 trans-18:2 ranged from 30% in the FFA to 77% in DPG. The second major isomer in all heart lipids was 9 cis,11 trans-18:2. In both liver and heart lipids the relative proportions of both 10 trans,12 cis-18:2 and 8 trans, 10 cis-18:2 were significantly lower compared to that found in the diet. The FFA in liver and heart showed the highest content of trans,trans isomers (31 to 36%) among all the lipid classes. The preferential accumulation of the 11 cis,13 trans-18:2 into cardiac lipids, and in particular the major phospholipid in the inner mitochondrial membrane, DPG, in both heart and liver, appears unique and may be of concern. The levels of 11 cis,13 trans-18:2 naturally found in foods have not been established.
从61.5千克体重到106千克体重期间，给猪饲喂基础日粮中添加2%由向日葵油碱异构化制备的商业共轭亚油酸（CLA）混合物，并与饲喂添加2%向日葵油的相同基础日粮的猪进行比较。分析了饲喂CLA日粮的猪的肝脏、心脏、背部内侧脂肪和网膜脂肪中的总脂质，以确定CLA异构体在所有组织脂质类别中的掺入情况。通过三向薄层色谱法分离出总共10种脂质类别，并通过长毛细管柱气相色谱法（GC）和银离子高效液相色谱法（Ag+-HPLC）进行分析；采用分光光度法测定胆固醇。在饲喂对照日粮的猪中仅观察到痕量（<0.1%；通过GC）的9,11-18:2顺式/反式和反式，反式异构体。日粮和猪组织脂质中的CLA异构体分别通过GC和Ag+-HPLC分离。不同脂质类别中所有CLA异构体的相对浓度占总脂肪酸的1%至6%。四种主要的顺式/反式异构体（18.9%的11顺式，13反式-18:2；26.3%的10反式，12顺式-18:2；20.4%的9顺式，11反式-18:2；以及16.1%的8反式，10顺式-18:2）占日粮CLA混合物中总CLA异构体的82%，并且存在少量相应的顺式，顺式（7.4%）和反式，反式（10.1%）异构体。猪背部内侧脂肪和网膜脂肪中CLA异构体的分布与日粮中的相似。肝脏三酰甘油（TAG）、游离脂肪酸（FFA）和胆固醇酯呈现出与日粮中相似的模式。主要的肝脏磷脂中9顺式，11反式-18:2显著增加，范围从36%到54%，相比日粮中的含量。然而，肝脏双磷脂酰甘油（DPG）中11顺式，13反式-18:2异构体的掺入量很高（43%）。除TAG外，所有心脏脂质类别中11顺式，13反式-18:2的含量都很高，这与肝脏中的结果形成明显对比。11顺式，13反式-18:2的相对比例在FFA中为30%，在DPG中为77%。所有心脏脂质中的第二主要异构体是9顺式，11反式-18:2。在肝脏和心脏脂质中，10反式，12顺式-18:2和8反式，10顺式-18:2的相对比例与日粮中的相比均显著降低。肝脏和心脏中的FFA在所有脂质类别中反式，反式异构体的含量最高（31%至36%）。11顺式，13反式-18:2优先积累到心脏脂质中，特别是心脏和肝脏中线粒体内膜的主要磷脂DPG中，这似乎是独特的，可能值得关注。食物中天然存在的11顺式，13反式-18:2的水平尚未确定。
