大黄素、维生素C及其配伍对团头鲂感染嗜水气单胞菌后生理生化指标的影响

为综合评价大黄素、高剂量维生素C及其配伍对团头鲂(Megalobrama amblycephala Yih)抗嗜水气单胞菌感染能力的影响,选取1 200尾健康的团头鲂,体质量为(133.44±2.11)g,随机分成4组,其中1组为对照组,投喂基础日粮,另外3组在基础日粮中分别添加60mg/kg大黄素、700 mg/kg维生素C、60mg/kg大黄素+700mg/kg维生素C(配伍组).饲养60 d后,经腹腔注射感染嗜水气单胞菌,并在攻毒前后检测团头鲂血液和肝脏的生化指标以及肝脏2种热休克蛋白70s(HSP70s)mRNA的表达水平;另从各池中取10尾鱼进行同样的攻毒试验,统计攻毒后各时间点鱼的累积死亡率.结果表明,攻毒后,与对照组相比,大黄素、维生素C组不同程度地提高了血清总蛋白(TP)、溶菌酶(LSZ)和碱性磷酸酶(AKP)的水平,肝脏超氧化物歧化酶(SOD)和过氧化氢酶(CAT)的活性以及HSC70和HSP70 mRNA的表达水平,降低了血清皮质醇(COR)、血糖(GLU)、谷丙转氨酶(GPT)、谷草转氨酶(GOT)、甘油三酯(TG)以及肝脏丙二醛(MDA)的水平;配伍组中,这些指标的变化趋势虽与上述类似,但大多与对照组的差异不显著(P＞0.05),且未表现出协同增效作用.此外,各组鱼血清胆固醇(CHOL)的含量在攻毒前后的差异均不显著(P＞0.05).统计也表明,大黄素和维生素C组鱼的累积死亡率在攻毒后24 h、48 h均显著低于对照组(P＜0.05),而配伍组试验鱼的累积死亡率与对照组差异均不显著(P＞0.05).由此可见,在基础日粮中添加大黄素60 mg/kg或维生素C 700 mg/kg,可提高鱼体的非特异性免疫力、抗氧化能力以及2种HSP70s mRNA的表达水平,增强鱼体抗病原菌感染的能力.二者配伍则效果不佳.

Effects of emodin, vitamin C and their combination on biochemical parameters and two HSP70s mRNA expression of Wuchang bream (Megalobrama amblycephala) infected with Aeromonas hydrophila

The study aims to evaluate the effects of dietary emodin, high-dose vitamin C (Vc) and their combination on the disease resistance of Aeromonas hydrophila infection. One thousand and two hundred healthy fish with initial body weight of (133.44±2.11) g were selected and randomly divided into four groups: one was the control group fed with basal diet (containing Vc 50.3 mg/kg, with the L-ascorbyl-2-polyphosphate as Vc source); the other three were the treatment groupsnted with emodin 60 mg /kg, Vc 700 mg/kg, and the combination of emodin 60 mg/kg + Vc 700 mg/kg, A. hydrophilathe biochemical parameters of serum and liver, the mRNA levels of two heat shock protein 70s (HSP70s) in liver infection were determined. Another ten fish taken from each tank were challenged with using the same method as above, and the cumulative mortality of each group was counted at different time of post-infection. The results showed that before infection, compared with the control group, serum total protein (TP), lysozyme (LSZ) and alkaline phosphatase (AKP) levels, liver superoxide dismutase (SOD) activity and expression level of inducible HSP70 mRNA significantly increased , while serum cortisol (COR), triglyceride (TG) and liver malondialdehyde (MDA) contents decreased ( <0.05) in emodin and Vc groups; the liver catalase (CAT) activity also significantly increased in <0.05). Although the serum TP, LSZ and liver HSP70 mRNA levels significantly increased , and the liver malondialdehyde (MDA) level was also significantly reduced (<0.05), no synergism was shown.After infection, compared with the control group, the serum TP, LSZ, AKP levels, liver SOD, CAT activities, and the expression levels of HSC70 and HSP70 mRNA increased in varying degrees, while the serum COR, glucose (GLU), combination group, although these parameters had similar changing trend as the above ones, most of them were not significant different with the control (> 0.05), and also did not . Statistic data also showed that after infection with A. hydrophi1asignificantly lower than the control group was not significant (> 0.05). could improve non-specific immunity of fish, capacity, and two HSP70s mRNA expression However, the combination of emodin and high-dose Vc showed no better effect, and the mechanism of their interaction