CAJ | 학술논문

采用人工受精获得的南方鲇 Silurus meridionalis Chen胚胎和仔鱼为实验对象，以Pb（NO3）2为毒物源，在水温22.5℃条件下，观察了水体中不同质量浓度铅（Pb）暴露对南方鲇胚胎孵化率、畸形率、自主运动、孵化历时的影响，并进行了初孵仔鱼的Pb暴露毒理实验．实验结果表明，在水体中Pb2＋质量浓度分别为0（对照），4，8，12和16 mg／L的条件下，南方鲇胚胎孵化率随着Pb质量浓度的上升呈下降趋势，分别为84.94％，71.23％，69.75％，66.57％和64.69％，各Pb质量浓度处理组的孵化率显著低于对照组（ p＜0.05）；且孵出的仔鱼出现心包水肿，脊柱弯曲以及尾巴弯曲退化等畸形特征，畸形率随着 Pb质量浓度的升高呈上升趋势，分别为10.27％，15.28％，22.28％和36.67％，各Pb暴露组均显著高于对照组（2.37％）（ p＜0.05）；各Pb质量浓度暴露组胚胎在出膜前期的自主运动频率分别为63.86，52.71，48.43和47.14次／min均显著低于对照组（78.00次／min）（p＜0.05）；各Pb质量浓度暴露组的胚胎孵化历时均显著长于对照组（p＜0.05）．孵化后在净水（未加入Pb（NO3）2的实验水体）中养殖的卵黄囊期仔鱼72 h死亡率随着其胚胎期Pb暴露质量浓度的上升呈上升趋势，胚胎期Pb暴露质量浓度分别为0，4，8，12和16 m g／L的条件下，仔鱼期的净水死亡率分别为9.45％，18.22％，20.95％，24.05％和26.29％，胚胎期各Pb质量浓度暴露组所获仔鱼的死亡率均显著高于对照组（ p＜0.05）．根据水体 Pb暴露对南方鲇初孵仔鱼急性中毒致死的观测结果推算，其96 h半致死质量浓度（96 h LC50）为0.32 mg／L ．本研究结果表明，南方鲇胚胎对水体Pb暴露的耐受性高于其初孵仔鱼，可能与南方鲇的受精卵卵膜较厚，对水体中的Pb2＋进入胚胎具有较大的阻滞作用有关．
채용인공수정획득적남방점 Silurus meridionalis Chen배태화자어위실험대상，이Pb（NO3）2위독물원，재수온22.5℃조건하，관찰료수체중불동질량농도연（Pb）폭로대남방점배태부화솔、기형솔、자주운동、부화력시적영향，병진행료초부자어적Pb폭로독리실험．실험결과표명，재수체중Pb2＋질량농도분별위0（대조），4，8，12화16 mg／L적조건하，남방점배태부화솔수착Pb질량농도적상승정하강추세，분별위84.94％，71.23％，69.75％，66.57％화64.69％，각Pb질량농도처리조적부화솔현저저우대조조（ p＜0.05）；차부출적자어출현심포수종，척주만곡이급미파만곡퇴화등기형특정，기형솔수착 Pb질량농도적승고정상승추세，분별위10.27％，15.28％，22.28％화36.67％，각Pb폭로조균현저고우대조조（2.37％）（ p＜0.05）；각Pb질량농도폭로조배태재출막전기적자주운동빈솔분별위63.86，52.71，48.43화47.14차／min균현저저우대조조（78.00차／min）（p＜0.05）；각Pb질량농도폭로조적배태부화력시균현저장우대조조（p＜0.05）．부화후재정수（미가입Pb（NO3）2적실험수체）중양식적란황낭기자어72 h사망솔수착기배태기Pb폭로질량농도적상승정상승추세，배태기Pb폭로질량농도분별위0，4，8，12화16 m g／L적조건하，자어기적정수사망솔분별위9.45％，18.22％，20.95％，24.05％화26.29％，배태기각Pb질량농도폭로조소획자어적사망솔균현저고우대조조（ p＜0.05）．근거수체 Pb폭로대남방점초부자어급성중독치사적관측결과추산，기96 h반치사질량농도（96 h LC50）위0.32 mg／L ．본연구결과표명，남방점배태대수체Pb폭로적내수성고우기초부자어，가능여남방점적수정란란막교후，대수체중적Pb2＋진입배태구유교대적조체작용유관．
To determine the toxic effects of waterborne Lead (Pb) on embryonic and larval development of the southern catfish (Silurus meridionalis Chen) ,the embryos and larvae which have been bred with arti-ficial fertilization have been exposed to Pb solutions of five nominal concentrations (0 ,4 ,8 ,12 and 16 mg/L) at 22 .5℃ respectively .Embryonic hatching rate ,larval malformation rate ,spontaneous movements , incubation period have been evaluated at the end of embryonic period . Acute toxicity of Pb to newly hatched larvae has also been determined in this study .Embryonic hatchability has decreased with the in-creasing Pb concentration .The value in the groups of 4 ,8 ,12 and 16 mg/L were 71 .23% ,69 .75% ,66 .57%and 64 .69% respectively ,which are significantly lower compared with the control group (84 .94% ) (p<0 .05) .Furthermore ,exposure of embryos to Pb has significantly increased morbidity of body malforma-tions in newly hatched larvae ,such as pericardial edema ,body curvature and degenerated tail .In the groups of 4 ,8 ,12 and 16 mg/L ,the malformation rate of newly larvae are 10 .27% ,15 .28% ,22 .28%and 36 .67% respectively ,which are significantly lower than that of the control group (2 .37% ) (p<0 .05) .The average spontaneous movements of embryos decreased along the contamination gradient .In the concentrations of 4 ,8 ,12 and 16 mg/L ,the value are 63 .86 ,52 .71 ,48 .43 and 47 .14 beats/min , which are significantly lower compared with the control group (78 .00 beats/min) before hatching (44 hours post-fertilization) (p<0 .05) .Pb also has an inhibitory effect on hatching time .The incubation peri-ods are significantly delayed compared to control (p<0 .05) .Exposures to waterborne Pb during embryon-ic period alone causes adverse impact on larval performance even w hen larval development took place in clean w ater .And the lowest larval mortality in 72 hours after hatching occurred in the control group (9 .45% ) , which is significantly lower than that in other groups (18 .22% ,20 .95% ,24 .05% and 26 .29% ) (p<0 .05) . The results in toxic test of Pb to newly hatched larvae show that the median lethal concentration in 96 hours (96h LC50) is 0 .32 mg/L .These results suggest that larvae are more sensitive to Pb toxicity than embryos in southern catfish .Thicker membrane in fertilized egg might have blocking effects to waterborne Pb ,w hich may be one of the most important reason w hy the embryos had higher tolerance to Pb .