两种温度下大黄素对团头鲂生长、血液指标及肝脏HSP70 mRNA表达的影响

摘要

A 2×2 factorial design was used to evaluate the effects of dietary emodin on growth, haematological parame-ters and heat shock protein 70 (HSP70) mRNA expression of Wuchang bream (Megalobrama amblycephala) at two temperatures. Three hundred healthy fish (average initial weight of 7.29±0.01 g) were selected and randomly divided into four groups rearing at 25℃ and 30℃. At each temperature, the fish were fed with basal diets and supplemented with 25 mg/kg emodin, respectively. Fish were held in tanks (φ820 mm×700 mm) and fed three times daily for 77 days. The results showed that, compared with those of fish reared at 25℃, the weight gain rate (WGR) and specific growth rate (SGR), hematocritg (HCT), lactate dehydrogenase (LDH) of the fish reared at 30℃were significantly increased, but the feed conversion ratio (FCR) and viserosomatic index (VSI), aspertate aminotransferase (AST), total bile acid (TBA) were significantly reduced. Compared with the control group, the SGR and liver body ratio (HSI), HCT, LDH of the emodin group were significantly increased, but the FCR and feeding rate (FR) significantly were reduced (P<0.05). For plasma urea (UREA), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triglycerides (TG), complement 3 (C3), complement 4 (C4) and the mRNA level of liver HSP70, there was an interaction between temperature and emodin (P<0.05). The UREA, TC, TG of the fish from the control group reared at 30℃ were lower than those at 25℃. Compared with the control, the C3, C4 and the mRNA level of liver HSP70 in emodin group were significantly increased (P<0.05) at 30℃, but no significant difference was found at 25℃(P>0.05). Other indices, such as condition factor (CF), serum glucose (GLU), alanine aminotransferase (ALT) activities, white blood cell (WBC), red blood cell (RBC), haemoglobin (HGB), showed no significant difference between the groups (P>0.05). The results indicated that the feed with 25 mg/kg emodin can help to alleviate the Wuchang bream blood physiological effects caused by long-term high temperature, improve the level of complements and liver HSP70 mRNA, and promote the growth of fish.%实验采用2×2双因子设计，研究两种温度下在饲料中添加大黄素对团头鲂(Megalobrama amblycephala)生长、血液生理反应及肝脏HSP70 mRNA表达的影响。选取300尾健康的团头鲂[初均重(7.29±0.01) g]，两种温度下(25℃、30℃)分别投喂不添加和添加25 mg/kg的大黄素配合饲料，养殖时间为77d。结果显示：在长期30℃高温下，鱼体增重率(WGR)和特定生长率(SGR)、红细胞积压(HCT)、乳酸脱氢酶(LDH)显著升高，饵料系数(FCR)和脏体比(VSI)、谷草转氨酶(AST)、总胆汁酸(TBA)显著下降(P<0.05)；添加25 mg/kg 大黄素， SGR和肝体比(HSI)、红细胞积压(HCT)、乳酸脱氢酶(LDH)显著升高，饵料系数(FCR)和摄食率(FR)显著下降(P<0.05)。温度和大黄素对谷丙转氨酶(ALT)和血糖(GLU)无显著影响(P>0.05)，对尿素(UREA)、甘油三酯(TG)、总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、补体3(C3)、补体4(C4)和肝脏HSP70 mRNA的相对含量存在显著交互作用(P<0.05)。与常温对照组相比，高温对照组UREA、TG、TC显著下降；在高温下，添加大黄素组UREA、TG、TC有升高趋势(P>0.05)， C3、C4和肝脏HSP70 mRNA的相对含量显著升高(P<0.05)。以上结果表明，在饲料中添加25 mg/kg大黄素有助于缓解长期高温对团头鲂血液生理的影响，提高补体水平和肝脏HSP70 mRNA的相对含量，促进鱼体的生长。