虎杖对注射无乳链球菌红罗非鱼肝脏酶活性的影响

Effects of Polygonum cuspidatum on Liver Enzyme Activity of Red Tilapia Injected with Streptococcus agalactiae

为探究虎杖粗提物和白藜芦醇对注射无乳链球菌红罗非鱼肝脏酶活的影响,在本实验中将红罗非鱼随机分为24组,12组投喂基础日粮,为不加药组,另外12组投喂添加了虎杖粗提物和白藜芦醇的基础日粮,为加药组。在加药组与不加药组中各选取3小组鱼分别注射3个浓度梯度的无乳链球菌菌液,同时设置不注射菌液的对照组,连续观察21 d并记录死亡数量。21 d后检测活鱼肝脏组织中的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、丙二醛(MDA)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)和溶菌酶(LZM)的活性。结果显示,当受到低浓度(7×10^(3)CFU/mL)无乳链球菌胁迫时,虎杖粗提物和白藜芦醇可通过增强红罗非鱼鱼体的抗氧化能力来降低链球菌对机体的损害;当受到高浓度(7×10^(5)CFU/mL)无乳链球菌胁迫时,虎杖粗提物和白藜芦醇则通过诱导肝脏中磷酸酶的活性来提高鱼体的抗病力。同时,虎杖粗提物和白藜芦醇在投喂12 d后可使注射无乳链球菌红罗非鱼的死亡率不再增加。该实验表明高、低浓度无乳链球菌胁迫时,虎杖粗提物和白藜芦醇可降低链球菌对鱼体的损害,且控制死亡率。

In order to explore the effect of Polygonum cuspidatum crude extract and resveratrol on the liver enzyme activity of red tilapia injected with Streptococcus agalactiae,the red tilapia(Oreochromis mossambicus×O.niloticus)were randomly divided into 24 groups,12 groups were fed normal diet(no drug addition group),and other 12 groups were fed diet supplemented with P.cuspidatum crude extract and resveratrol(drug addition group)in this study.Three groups of fish were selected from the drug addition group and the no drug addition group to inject S.agalactiae bacterial solution at three concentration gradients respectively.At the same time,the control group was set up without injection of bacterial solution,and all groups were continuously observed for 21 days,and the number of deaths was recorded.The activity of superoxide dismutase(SOD),catalase(CAT),malondialdehyde(MDA),acid phosphatase(ACP),alkaline phosphatase(AKP)and lysozyme(LZM)in the liver of red tilapia were tested after 21 days.The result showed that P.cuspidatum crude extract and resveratrol reduced the body damage of S.agalactiae by enhancing the antioxidant ability of red tilapia in the low concentration(7×10^(3) CFU/mL)of S.agalactiae groups.When fish were exposed to high concentration(7×10^(5) CFU/mL)of S.agalactiae,P.cuspidatum crude extract and resveratrol increased the resistance of fish by inducing the activity of phosphatase in the liver.At the same time,the crude extract of P.cuspidatum and resveratrol kept the mortality rate of red tilapia injected with S.agalactiae unchanged after 12 days.This experiment showed that P.cuspidatum crude extract and resveratrol could reduce the damage of S.agalactiae to fish and control the mortality under high and low concentrations of S.agalactiae stress.