不同脂肪酸构成比对大鼠血脂影响的研究

Effect of different fatty acid compositions on blood lipid of rats

目的探讨不同膳食脂肪酸构成对大鼠血脂水平的影响。方法用含15%脂肪(质量分数)的半合成饲料喂养雌性SD大鼠。大鼠48天龄时,按体质量随机分成6组喂养6种不同膳食脂肪酸组成的饲料,即饱和脂肪酸组(SFA)、单不饱和脂肪酸组(MUFA)、n-6多不饱和脂肪酸组(n-6PUFA)、n-3多不饱和脂肪酸组(n-3PUFA)、1∶1n-6/n-3组及普通饲料喂养组,持续喂养18周。观察各组大鼠每周的体质量增长情况,并在实验8周和18周检测各组大鼠的血脂水平。结果除n-3PUFA喂养组大鼠在实验6周后出现体质量增长受阻外,其余各组大鼠体质量在实验期内均无明显差异(P<0.05)。实验第8周,与对照组相比较,SFA组大鼠血清LDL-C水平显著升高(P<0.05),n-3PUFA组、1∶1n-6/n-3组血清TG、TC、LDL-C、TC/HDL-C、LDL-C/HDL-C均显著降低(P<0.05),且血清HDL-C水平显著升高(P<0.05),n-6PUFA组血清TG、LDL-C、TC/HDL-C的水平显著降低(P<0.05)。至实验末期,与对照组比较,SFA组大鼠血清TG、TC、LDL-C、TC/HDL-C、LDL-C/HDL-C水平均显著升高,且HDL-C水平显著降低(P<0.05),MUFA组、n-6PUFA组、n-3PUFA组血清TG、TC、LDL-C、TC/HDL-C、LDL-C/HDL-C均显著降低(P<0.05),同时血清HDL-C水平显著升高(P<0.05),而1∶1n-6/n-3组变化更加显著(P<0.01);同时,1∶1n-6/n-3组大鼠血清的LDL-C/HDL-C值显著低于MUFA组及n-6PUFA组(P<0.05)。结论1∶1n-6/n-3PUFA的脂肪酸摄入比例能最有效地调节血脂水平,从而有利于预防心血管疾病的发生。

Objective To study the effect of different dietary fatty acid compositions on blood lipid metabolism of rats. Methods Female SD rats were fed diets containing 15% fat in the experimental period. At age of 48 d, the rats were randomly assigned into 6 groups respectively fed 6 different diets, respectively containing following fatty acids： saturated fatty acid （SFA）, monounsaturated fatty acid （MUFA）, n-6 polyunsaturated fatty acid （PUFA）, n-3 PUFA, 1：1 n-6/n-3 for 18 weeks. The weight was observed every week, and the concentration of blood lipids was measured at end of 8, 18 weeks. Results Except the obstacle of weight growth in n-3 PUFA group since the 6th week, there was no significant difference among the other groups. As compared with control group at the end of 8 weeks, the serum levels of triglycerol （ TG）, total cholesterol （ TC）, and low density lipoprotein cholesterol （LDL-C）, TC/HDL-C, LDL-C/HDL-C in n-3 PUFA and 1：1 n-6/n-3 groups decreased significantly （ P 〈 0.05 ）, and high density lipoprotein cholesterol （ HDL-C ） increased obviously （P 〈 0.05 ） ; the serum levels of TG, LDL-C, TC/HDL-C in n-6 PUFA group decreased obviously （P 〈 0.05） ; the serum levels of LDL-C in SFA group increased obviously （P 〈0.05）. At the end of 18 weeks, the serum levels of TG, TC, and LDL-C, TC/HDL-C, LDL-C/HDL-C in MUFA, n-6 PUFA, n-3 PUFA and 1：1 n-6/n-3 groups decreased obviously （ P 〈 0.05）, and HDL-C increased obviously （ P 〈 0.05 ）, while the serum levels of these parameters in SFA group increased except increased HDL-C. As compared with 1：1 n-6/n-3 group, the ratio of LDL-C/HDL-C in MUFA and n-6 PUFA groups decreased obviously （P 〈 0.05）. Conclusion 7The composition ratio of 1：1 for n-6/n-3 was the most efficient in decreasing the levels of blood lipids and beneficial to preventing cardiovascular diseases.