Hwang Yun-Hee, Kang Keum-Jee
Department of Food and Nutrition, College of Natural Sciences, Duksung Women's University, Seoul, Korea.
Ann Nutr Metab. 2007;51(2):126-33. doi: 10.1159/000103272. Epub 2007 May 29.
This study investigated the effects of conjugated linoleic acid (CLA) on the body weight, fat deposition and the expression of stearoyl coenzyme A desaturase 1 (SCD1) in the livers of male ICR mice that were fed with either beef tallow (BT) or fish oil (FO) supplemented with CLA. Mice weighing 25-30 g were divided into four groups, BT and BT supplemented with 0.5% CLA (BTC), FO and FO supplemented with 0.5% CLA (FOC). Each group consisted of 8 mice, and they were fed the experimental diets for 4 weeks. The experimental diets were composed of 59.18% carbohydrates, 19.73% proteins and 21.09% fat in terms of their contributions to total calories, and other nutrients were identical. CLA was added to the diets of the CLA supplementation groups at 0.5% (w/w). The measurement of triglyceride (TG) was done by using a kit. Fatty acid compositions were analyzed in both the plasma and the liver using a gas chromatograph. The levels of SCD1 expression were analyzed by RT-PCR in the liver.
No significant difference was found in the levels of food intake, body weight and food efficiency among experimental groups. However, the levels of both epididymal and visceral fat weight were significantly lower in the CLA-supplemented groups, BTC and FOC (p < 0.05). The level of the triglyceride concentration was also significantly lower in the CLA-supplemented groups (p < 0.05). The levels of the liver SCD1 gene expression were also higher in the CLA-supplemented groups. However, significant inhibition of conversion from C16:0 to C16:1 was found in both fatty acid compositions of the liver (p < 0.05).
Addition of 0.5% CLA did not inhibit the liver SCD1 gene expression; however, it showed decreasing effects on the fat pad weight, the concentration of TG and on fatty acid composition, leading to a decrease in the fat depositions. Such effects were clearer when CLA was supplemented to BT rather than FO.
本研究调查了共轭亚油酸（CLA）对喂食牛脂（BT）或添加CLA的鱼油（FO）的雄性ICR小鼠体重、脂肪沉积以及肝脏中硬脂酰辅酶A去饱和酶1（SCD1）表达的影响。将体重25 - 30克的小鼠分为四组：BT组、添加0.5% CLA的BT组（BTC）、FO组、添加0.5% CLA的FO组（FOC）。每组8只小鼠，给予实验饲料4周。实验饲料按对总热量的贡献计，碳水化合物占59.18%、蛋白质占19.73%、脂肪占21.09%，其他营养素相同。CLA以0.5%（w/w）添加到CLA补充组的饲料中。使用试剂盒测定甘油三酯（TG）。用气相色谱仪分析血浆和肝脏中的脂肪酸组成。通过RT - PCR分析肝脏中SCD1的表达水平。
实验组之间的食物摄入量、体重和食物效率水平无显著差异。然而，补充CLA的组BTC和FOC的附睾脂肪和内脏脂肪重量水平显著更低（p < 0.05）。补充CLA的组中甘油三酯浓度水平也显著更低（p < 0.05）。补充CLA的组中肝脏SCD1基因表达水平也更高。然而，在肝脏的两种脂肪酸组成中均发现从C16:0到C16:1的转化受到显著抑制（p < 0.05）。
添加0.5% CLA并未抑制肝脏SCD1基因表达；然而，它对脂肪垫重量、TG浓度和脂肪酸组成有降低作用，导致脂肪沉积减少。当CLA添加到BT中而非FO中时，这种效果更明显。
