本试验旨在研究绿茶粉和绿茶多酚对犬的降脂作用，并初步揭示其降脂作用的机理。试验选择15只健康的5月龄本地田园犬，随机分为3组，每组5只。对照组饲喂基础饲粮，绿茶粉组饲喂在基础饲粮中添加1.00%绿茶粉的试验饲粮，绿茶多酚组饲喂在基础饲粮中添加0.25%绿茶多酚的试验饲粮。试验期为12周。结果显示：1）在整个试验过程中，3组犬的体重整体呈增长趋势。与对照组相比，绿茶粉组体重于第4周开始出现显著降低（P<0.05），并一直保持到试验结束（第12周）；绿茶多酚组体重则于第6周开始出现显著差异（P<0.05），之后（第7、8、9、10周）又波动到无显著差异（P>0.05），在最后2周（第11、12周）又出现显著差异（P<0.05）。2）试验第7~12周，绿茶粉组和绿茶多酚组犬血清总胆固醇（TC）和低密度脂蛋白胆固醇（LDL-C）含量均显著低于对照组（P<0.05）；试验第8~12周，绿茶粉组和绿茶多酚组犬血清甘油三酯（TG）含量显著低于对照组（P<0.05）；试验第6~12周，绿茶粉组和绿茶多酚组犬血清高密度脂蛋白胆固醇（HDL-C）含量显著高于对照组（P<0.05）。3）与对照组相比，绿茶粉和绿茶多酚均能显著降低犬肝组织乙酰辅酶A羧化酶α（ACCα）、脂肪酸合成酶（FAS）、载脂蛋白B-100（ApoB-100）mRNA的相对表达量（P<0.05），且能显著升高载脂蛋白A-1（ApoA-1）、过氧化物酶体增殖物活化受体α（PPARα）、酰基辅酶A氧化酶（ACO）mRNA的相对表达量（P<0.05）。与对照组相比，绿茶粉组犬肝组织脂肪酸转位酶（CD36）mRNA的相对表达量无显著变化（P>0.05），而绿茶多酚组犬肝组织CD36 mRNA的相对表达量则显著升高（P<0.05）。由此得出，本试验条件下，在饲粮中添加1.00%绿茶粉或0.25%绿茶多酚均能够有效控制犬的体重，调节犬体内的脂代谢，降低犬肝组织中ACCα、FAS、ApoB-100 mRNA的相对表达量，提高犬肝组织中ApoA-1、CD36、PPARα、ACO mRNA的相对表达量，从而发挥降脂作用。

The current study aimd to study the lipid-lowering effect of green tea powder and green tea polyphenols in canines, and to reveal the mechanism of lipid-lowering effect. The experiment selected 15 healthy 5-month-old local pastoral canines, and randomly divided into 3 groups with 5 canines in each group. The canines in control group were fed a basal diet, the canines in green tea powder group were fed the basal diet supplemented with 1.00% green tea powder, and the canines in green tea polyphenols group was fed the basal diet supplemented with 0.25% green tea polyphenols. The trial lasted for 12 weeks. The results showed as follows: 1) during the whole experiment period, the body weight of 3 groups showed an increasing trend, and the body weight of green tea powder group and green tea polyphenols group were significantly lower than that of control group. Compared with the control group, the body weight of green tea powder group began to show significant difference in the 4th week (P<0.05), and remained difference until the end of the experiment (the 12th week); the body weight of green tea polyphenol group began to show significant difference in the 6th week (P<0.05), and then (the 7th, 8th, 9th and 10th week) fluctuated to no significant difference (P>0.05), and in the last two weeks (the 11th and 12th week) showed significant difference (P<0.05). 2) The contents of serum total cholesterol (TC) and low density lipoprotein cholesterin (LDL-C) in the 7th to 12th week of green tea powder group and green tea polyphenols group were significantly lower than those of control group (P<0.05); the content of serum triglyceride (TG) in the 8th to 12th week of green tea powder group and green tea polyphenols group was significantly lower than that of control group (P<0.05); the content of serum high density lipoprotein cholesterol (HDL-C) in the 6th to 12th week of green tea powder group and green tea polyphenols group was significantly higher than that of control group (P<0.05). 3) Compared with the control group, both green tea powder group and green tea polyphenols group could significantly decrease the mRNA relative expression levels of acetyl CoA carboxylase α (ACCα), fatty acid synthase (FAS) and apolipoprotein B-100 (ApoB-100) (P<0.05), and could significantly increase the mRNA relative expression levels of apolipoprotein A-1(ApoA-1), peroxisome proliferators-activated receptor α (PPARα) and acyl-CoA oxidase (ACO) in canine hepatic tissue (P<0.05). The mRNA relative expression level of fatty acid translocase (CD36) in canine hepatic tissue of green tea powder group was not significantly different from that in control group (P>0.05), and it of green tea polyphenol group was significantly higher than that of control group in canine hepatocytes (P<0.05). Under this experimental condition, the results indicate that 1.00% green tea powder or 0.25% green tea polyphenols added to the canine diets can effectively control the body weight of canines, regulate the lipid metabolism in canines, decrease the mRNA relative expression levels of ACCα, FAS and ApoB-100 in canine hepatic tissue, increase the mRNA relative expression levels of ApoA-1, CD36, PPARα and ACO in canine hepatic tissue, and play an important role in lowering lipid.