于2007年10—12月,为探讨食物中多氯联苯126(3,3′,4,4′,5-pentachlorobiphenyl,PCB 126)对南方鲇(Silurus meridionalis Chen)的致死效应及代谢胁迫作用,将72尾南方鲇幼鱼分为6个实验组,配制PCB126含量分别为0、50、100、200、400和80...于2007年10—12月,为探讨食物中多氯联苯126(3,3′,4,4′,5-pentachlorobiphenyl,PCB 126)对南方鲇(Silurus meridionalis Chen)的致死效应及代谢胁迫作用,将72尾南方鲇幼鱼分为6个实验组,配制PCB126含量分别为0、50、100、200、400和800μg/kg的6组饲料,采用室内养殖系统,在(27.5±0.2)℃水温条件下以3%BW/d的日粮水平单尾喂养8周。观测结果表明:PCB126含量为0、50和100μg/kg的饲料组在实验期间无实验鱼死亡,至实验结束时的PCB126总摄入量分别为0、30.56和66.66μg/kg;而200、400和800μg/kg的饲料组有实验鱼死亡,半致死时间(Medianlethaltime,LT50)分别为34d、16d和11d,与饲料中PCB126水平呈负相关,至半致死时PCB126总摄入量分别为90.18、92.05和94.11μg/kg,三者间无显著差异,但均显著高于无实验鱼死亡饲料组的PCB126总摄入量(p<0.05);肝指数(Hepatosomatic index,HSI)及静止代谢率随饲料中PCB126水平的增加而升高;在无实验鱼死亡的饲料组,肝线粒体代谢耗氧率和细胞色素c氧化酶(Cytochrome c oxidase,CCO)活性随饲料中PCB126水平的增加而升高,而在有实验鱼死亡的饲料组,肝线粒体代谢耗氧率和CCO活性则随饲料中PCB126水平的增加而呈下降趋势。本研究提出,PCB126对南方鲇的致死临界累计摄入量在92μg/kg左右;PCB126对南方鲇在整体水平表现为使静止代谢增强的胁迫效应,但在肝线粒体水平表现为低浓度使其代谢耗氧率增强,这应当是该种鱼应对多氯联苯类污染物的一种生理调节结果,而高浓度的PCB126则使肝脏功能受到不可耐受的损害,不能对胁迫做出进一步的代谢调节。展开更多
【目的】探明莱氏野村菌Nr0815对不同龄期斜纹夜蛾幼虫的毒力。【方法】采用浸渍法分别测定莱氏野村菌菌悬液对斜纹夜蛾2~5龄幼虫的致病死亡率。【结果】从校正死亡率来看,对同一龄期斜纹夜蛾幼虫接种时,幼虫的校正死亡率均随着接种浓...【目的】探明莱氏野村菌Nr0815对不同龄期斜纹夜蛾幼虫的毒力。【方法】采用浸渍法分别测定莱氏野村菌菌悬液对斜纹夜蛾2~5龄幼虫的致病死亡率。【结果】从校正死亡率来看,对同一龄期斜纹夜蛾幼虫接种时,幼虫的校正死亡率均随着接种浓度的升高而增加,不同接种浓度间幼虫的校正死亡率均存在显著性差异(P<0.05);各龄期间的校正死亡率在10~7 m L–1接种密度下无显著性差异(P>0.05),10~3~10~6和10~8 m L–1接种密度下均存在显著性差异(P<0.05);且以2龄幼虫的校正死亡率最高。从致死中密度来看,不同龄期的致死中密度LC50间存在极显著性差异(P<0.05)。且龄期敏感性随龄期的增大而减弱;对2~5龄幼虫的LC50分别为(2.63±0.25)×10~4、(4.79±0.18)×10~5、(8.04±0.21)×10~5、(2.20±0.25)×10~6 m L–1。从致死中时来看,接种密度为2.18×10~8 m L–1时,对2~5龄幼虫的致死中时LT50分别为4.72、6.24、6.09、6.88 d。【结论】莱氏野村菌Nr0815对斜纹夜蛾2~5龄幼虫具有一定的致病效果,且对2龄幼虫的致病力最强。展开更多
Total dissolved gas(TDG) supersaturation caused by dam sluicing can result in gas bubble trauma(GBT) in fish and threaten their survival.In the present study,Chinese suckers(Myxocyprinus asiaticus Bleeker) were expose...Total dissolved gas(TDG) supersaturation caused by dam sluicing can result in gas bubble trauma(GBT) in fish and threaten their survival.In the present study,Chinese suckers(Myxocyprinus asiaticus Bleeker) were exposed to TDG supersaturated water at levels ranging from 120% to 145% for 48 h.The median lethal concentration(LC 50) and the median lethal time(LT 50) were determined to evaluate acute lethal effects on Chinese suckers.The results showed that the LC 50 values of 4,6,8,and 10 h were 142%,137%,135%,and 130%,respectively.The LT 50 values were 3.2,4.7,7.8,9.2,and 43.4 h,respectively,when TDG supersaturated levels were 145%,140%,135%,130%,and 125%.Furthermore,the biological responses in Chinese suckers were studied by assaying the catalase(CAT) activities in gills and muscles at the supersaturation level of 140% within LT 50.The CAT activities in the gills and muscle tissues exhibited a regularity of a decrease after an increase.CAT activities in the muscles were increased significantly at 3/5LT 50(P<0.05) and then came back to the normal level.However,there were no significant differences between the treatment group(TDG level of 140%) and the control group(TDG level of 100%) on CAT activities in the gills before 3/5LT 50(P>0.05),but the activities were significantly lower than the normal level at 4/5LT 50 and LT 50(P<0.05).展开更多
文摘于2007年10—12月,为探讨食物中多氯联苯126(3,3′,4,4′,5-pentachlorobiphenyl,PCB 126)对南方鲇(Silurus meridionalis Chen)的致死效应及代谢胁迫作用,将72尾南方鲇幼鱼分为6个实验组,配制PCB126含量分别为0、50、100、200、400和800μg/kg的6组饲料,采用室内养殖系统,在(27.5±0.2)℃水温条件下以3%BW/d的日粮水平单尾喂养8周。观测结果表明:PCB126含量为0、50和100μg/kg的饲料组在实验期间无实验鱼死亡,至实验结束时的PCB126总摄入量分别为0、30.56和66.66μg/kg;而200、400和800μg/kg的饲料组有实验鱼死亡,半致死时间(Medianlethaltime,LT50)分别为34d、16d和11d,与饲料中PCB126水平呈负相关,至半致死时PCB126总摄入量分别为90.18、92.05和94.11μg/kg,三者间无显著差异,但均显著高于无实验鱼死亡饲料组的PCB126总摄入量(p<0.05);肝指数(Hepatosomatic index,HSI)及静止代谢率随饲料中PCB126水平的增加而升高;在无实验鱼死亡的饲料组,肝线粒体代谢耗氧率和细胞色素c氧化酶(Cytochrome c oxidase,CCO)活性随饲料中PCB126水平的增加而升高,而在有实验鱼死亡的饲料组,肝线粒体代谢耗氧率和CCO活性则随饲料中PCB126水平的增加而呈下降趋势。本研究提出,PCB126对南方鲇的致死临界累计摄入量在92μg/kg左右;PCB126对南方鲇在整体水平表现为使静止代谢增强的胁迫效应,但在肝线粒体水平表现为低浓度使其代谢耗氧率增强,这应当是该种鱼应对多氯联苯类污染物的一种生理调节结果,而高浓度的PCB126则使肝脏功能受到不可耐受的损害,不能对胁迫做出进一步的代谢调节。
文摘【目的】探明莱氏野村菌Nr0815对不同龄期斜纹夜蛾幼虫的毒力。【方法】采用浸渍法分别测定莱氏野村菌菌悬液对斜纹夜蛾2~5龄幼虫的致病死亡率。【结果】从校正死亡率来看,对同一龄期斜纹夜蛾幼虫接种时,幼虫的校正死亡率均随着接种浓度的升高而增加,不同接种浓度间幼虫的校正死亡率均存在显著性差异(P<0.05);各龄期间的校正死亡率在10~7 m L–1接种密度下无显著性差异(P>0.05),10~3~10~6和10~8 m L–1接种密度下均存在显著性差异(P<0.05);且以2龄幼虫的校正死亡率最高。从致死中密度来看,不同龄期的致死中密度LC50间存在极显著性差异(P<0.05)。且龄期敏感性随龄期的增大而减弱;对2~5龄幼虫的LC50分别为(2.63±0.25)×10~4、(4.79±0.18)×10~5、(8.04±0.21)×10~5、(2.20±0.25)×10~6 m L–1。从致死中时来看,接种密度为2.18×10~8 m L–1时,对2~5龄幼虫的致死中时LT50分别为4.72、6.24、6.09、6.88 d。【结论】莱氏野村菌Nr0815对斜纹夜蛾2~5龄幼虫具有一定的致病效果,且对2龄幼虫的致病力最强。
基金Project supported by the National Natural Science Foundation ofChina (No. 50979063)the Scientific Research Foundation for Young Teachers of Xihua University (No. Z1120412),China
文摘Total dissolved gas(TDG) supersaturation caused by dam sluicing can result in gas bubble trauma(GBT) in fish and threaten their survival.In the present study,Chinese suckers(Myxocyprinus asiaticus Bleeker) were exposed to TDG supersaturated water at levels ranging from 120% to 145% for 48 h.The median lethal concentration(LC 50) and the median lethal time(LT 50) were determined to evaluate acute lethal effects on Chinese suckers.The results showed that the LC 50 values of 4,6,8,and 10 h were 142%,137%,135%,and 130%,respectively.The LT 50 values were 3.2,4.7,7.8,9.2,and 43.4 h,respectively,when TDG supersaturated levels were 145%,140%,135%,130%,and 125%.Furthermore,the biological responses in Chinese suckers were studied by assaying the catalase(CAT) activities in gills and muscles at the supersaturation level of 140% within LT 50.The CAT activities in the gills and muscle tissues exhibited a regularity of a decrease after an increase.CAT activities in the muscles were increased significantly at 3/5LT 50(P<0.05) and then came back to the normal level.However,there were no significant differences between the treatment group(TDG level of 140%) and the control group(TDG level of 100%) on CAT activities in the gills before 3/5LT 50(P>0.05),but the activities were significantly lower than the normal level at 4/5LT 50 and LT 50(P<0.05).
