本试验采用高脂饲料诱导建立高脂血症罗非鱼模型,以研究发酵桑叶对高脂血症罗非鱼血脂、血糖水平的调节作用。将初始均重为45 g的450尾雄性吉富罗非鱼随机分成5组,每组设3个重复,每个重复30尾鱼。正常对照组罗非鱼饲喂基础饲料,其他4组罗非鱼在高脂血症模型建成后分别饲喂基础饲料(模型对照组),含7.5%和15.0%发酵桑叶的饲料(分别为发酵桑叶低剂量组和发酵桑叶高剂量组)以及含0.5%银杏黄酮的饲料(银杏黄酮组)。试验期为8周。结果表明:饲养5和8周后,模型对照组罗非鱼体重显著低于正常对照组、发酵桑叶低剂量组和发酵桑叶高剂量组以及银杏黄酮组(P<0.05),而发酵桑叶高剂量组罗非鱼的体重与正常对照组无显著差异(P>0.05)。发酵桑叶低剂量组、发酵桑叶高剂量组和银杏黄酮组罗非鱼血清总胆固醇(TCHO)、低密度脂蛋白胆固醇(LDL-C)含量和TCHO/高密度脂蛋白胆固醇(HDL-C)显著低于模型对照组(P<0.05),而发酵桑叶高剂量组罗非鱼血清TCHO、甘油三酯(TG)、LDL-C含量和TCHO/HDL-C与正常对照组无显著差异(P>0.05)。与模型对照组相比,发酵桑叶高剂量组和银杏黄酮组罗非鱼血清HDL-C含量显著升高(P<0.05)。与模型对照组相比,正常对照组、发酵桑叶低剂量组和发酵桑叶高剂量组以及银杏黄酮组罗非鱼血清超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性以及CAT/SOD显著升高(P<0.05),而血清丙二醛(MDA)含量和肝脂含量以及肝体指数(HSI)显著降低(P<0.05);而上述这些指标在发酵桑叶高剂量组与正常对照组之间无显著差异(P>0.05)。高脂饲料使模型对照组、发酵桑叶低剂量组、发酵桑叶高剂量组以及银杏黄酮组罗非鱼的血糖水平显著升高(0周,P<0.05);饲养8周后,发酵桑叶高剂量组和银杏黄酮组罗非鱼血糖水平显著低于模型对照组(P<0.05),而与正常对照组差异不显著(P>0.05)。由上可知,发酵桑叶能剂量依赖性地降低高脂血症罗非鱼的血脂、血糖水平,提高机体的抗氧化能力。

The models of hyperlipidemia tilapia induced by high-fat diet were established to explore the effects of fermented mulberry leaves on serum lipid and blood glucose levels of hyperlipidemia tilapia(Oreochromis niloticus). A total of 450 male GIFT tilapia with the initial average body weight of 45 g were randomly divided into 5 groups with 3 replicates per group, and 30 fish in each replicate. The fish in normal control group were fed with a basal diet, and the other 4 groups were fed the basal diet(model control group) and diets contained 7.5% and 15.0% fermented mulberry leaves(low level fermented mulberry leaves group and high level fermented mulberry leaves group, respectively), and 0.5% ginkgo flavone(ginkgo flavone group) after the establishment of the hyperlipidemia model, respectively. The experiment lasted for 8 weeks. The results showed as follows:after feeding 5 and 8 weeks, the body weight in model control group was significantly lower than that in normal control group, low level fermented mulberry leaves group, high level fermented mulberry leaves group and ginkgo flavone group(P<0.05), but no significant difference was found between high level fermented mulberry leaves group and normal control group(P>0.05). The serum total cholesterol(TCHO) and low-density lipoprotein cholesterol(LDL-C) contents and TCHO/high-density lipoprotein cholesterol(HDL-C) in low level fermented mulberry leaves group, high level fermented mulberry leaves group and ginkgo flavone group were significantly lower than those in model control group(P<0.05), but no significant differences were found in the serum TCHO, triglyceride(TG), LDL-C contents and TCHO/HDL-C between high level fermented mulberry leaves group and normal control group(P>0.05). Compared with the model control group, the serum HDL-C content in high level fermented mulberry leaves group and ginkgo flavone group was significantly increased(P<0.05). Compared with the model control group, the serum superoxide dismutase(SOD) and catalase(CAT) activities and CAT/SOD were significantly increased(P<0.05) and the serum MDA content, hepatopancreas lipid content and hepatosomatic index(HSI) were significantly decreased(P<0.05) in normal control group, low level fermented mulberry leaves group, high level fermented mulberry leaves group and ginkgo flavone group, but no significant differences were found in above indices between high level fermented mulberry leaves group and normal control group(P>0.05). High-fat diet could significantly increase the blood glucose level in model control group, low level fermented mulberry leaves group, high level fermented mulberry leaves group and ginkgo flavone group(0 week, P<0.05); after feeding 8 weeks, the blood glucose level in high level fermented mulberry leaves group and ginkgo flavone group was significantly decreased than that in model control group(P<0.05), but had no significant difference compared with normal control group(P>0.05). These results indicate that fermented mulberry leaves can decrease the serum lipid and blood glucose levels, and enhance the antioxidant ability of hyperlipidemia tilapia with a dose-dependent manner.