Toxicity of Cadmium and Its Bioaccumulation in Spotted Babylon,Babylonia areolata: Comparison between Effects of Waterborne and Dietary Exposure

为比较直接经水体与经营养传递的2种镉(CAdMIuM,Cd)暴露方式对方斑东风螺(bAbylOnIA ArEOlATA)不同组织Cd蓄积和毒性的差异,采用室内模拟法,将螺暴露于含Cd水体(Cd2+:100μg·l-1)或喂食含Cd饵料(牡蛎,34.56μg·g-1以干质量计,先经水体100μg·l-1Cd2+暴露达平衡)30d后再进行15d净化。结果显示,暴露期间,除食物相组螺胃肠道Cd浓度在第10天极显著高于对照组,但随后迅速下降外,其他各组织在2种途径及胃肠道在水相暴露时Cd的浓度均逐渐上升,暴露30d后肝胰脏中Cd浓度最高;净化期,螺鳃中Cd排出率较高,胃肠道与肝胰脏的排出率较低,至净化期末除食物相组鳃中Cd浓度与对照组无显著差异外,2种处理中其他各组织Cd浓度仍显著高于对照组。2种暴露途径中金属硫蛋白(METAllOTHIOnEIn,MT)浓度仅在螺肝胰脏中逐渐增加,且与Cd的蓄积呈显著线性正相关。与食物相组相比,水相Cd暴露引起螺肝胰脏脂质过氧化水平(lIPId PErOXIdATIOn,lPO)更高,且内脏团中Cd与其亚细胞成分的金属敏感组分结合的百分比也更高。结果表明,Cd通过营养传递对螺产生的毒性较水体直接暴露低,但摄食是螺蓄积Cd的主要途径;净化后除鳃外水相暴露组螺各组织Cd的排出率较低;因此为了健康养殖与食用安全,东风螺工厂化养成时对饵料与水体Cd浓度的监测均应引起足够的重视。The effects of waterborne and dietary cadmium ( Cd) exposure on bioaccumulation and toxicity in tissues of the Babylonia areolata juveniles were investigated.The snails were exposed to aqueous Cd ( 100 μg·L-1 Cd2+ )directly or fed with Cd pre-exposed oysters ( Saccostrea cucullata ) for 30 d.Cd concentration of the oysters was 34.56 μg·g-1 ( dry mass) after being exposed to waterborne Cd ( 100 μg·L-1 Cd2+ ) for 14 d,then the snails of the two treatments were depurated for another 15 d.The results indicated that the concentrations of Cd increased with increasing exposure time in all tissues except for the gastrointestinal tract of the dietary group,which decreased gradually after peaked at the 10 th day.The maximal values of Cd accumulated of the two treatments were both in hepatopancreas after 30 d exposure.After depuration,the efflux rates in gill were higher than those in gastrointestinal tract and hepatopancreas.Cd concentrations in different tissues were still significantly higher than that of the control group except for that in gill of the dietary group.The metallothionein ( MT) concentrations of the two treatments increased gradually only in hepatopancreas,which was positively correlated to the amount of the accumulated Cd.Comparedly,the toxicity to the snails after exposure to waterborne Cd was stronger than that after exposure to dietary Cd as more MDA contents produced in hepatopancreas and higher percentages of Cd distribution in metal sensitive fractions of the viscera.The snails accumulated Cd mainly from the diet.The depuration rates of tissues in the aqueous Cd group were lower than those in the dietary Cd group except for that of the gill.Therefore,much attention should be paid to monitor Cd concentrations of the diets and water when the snails were cultured with high-density in factory.广东海洋大学博士启动基金(1112328); 现代农业产业技术体系建设专项资金(CARS-48

我国鲍鱼养殖产业现状与展望

一、我国鲍鱼养殖发展历史的简要回顾鲍自古被誉为海味珍品之冠,素有“一口鲍鱼一口金“之说,是一类符合现代人追求的高蛋白、低脂肪的高级海鲜。鲍壳是著名的中药材石决明,又名千里光,有明目功效。其壳内珍珠层色彩绚丽,是制作装饰品和贝雕之佳品。自古以来人类就有捕捞鲍鱼的行业,但近代以来,由于自然环境变化加剧,鲍的自然资源日益减少,市场供不应求,导致价格攀升,因而鲍鱼人工养殖应运而生。在世界上66种鲍中,目前已开展人工养殖的有10余种,其

Cadmium bioaccumulation and its toxicity in Babylonia areolata under different nutritional status

采用室内模拟方式,研究了方斑东风螺在饥饿及摄食饵料分别为贻贝和沙蚕3种情况下暴露于水体镉(Cd2+,50μg·l-1)10周后的存活、生长、螺体Cd蓄积及有关毒性效应参数的变化.结果表明:长期饥饿与同时水体Cd暴露降低了方斑东风螺的成活率,且螺体糖原被最大程度动用,摄食有助于螺体抵抗Cd毒性;方斑东风螺肝胰脏dnA受损伤后在摄食状态下随时间延长均有不同程度的自我修复能力,但长期禁食使螺的dnA完整性降低且不能恢复;饥饿引起方斑东风螺体组织萎缩,并导致Cd蓄积与金属硫蛋白(MT)含量升高,摄食螺因体质量增加的稀释作用而具有较低的Cd蓄积与MT含量;摄食贻贝的方斑东风螺较摄食沙蚕有更快的生长率和更低的Cd浓度.表明饥饿加剧了Cd对方斑东风螺的毒性;不同饵料对方斑东风螺的生长有显著影响,并间接影响螺体Cd蓄积、MT诱导和糖原消耗.应用方斑东风螺等海洋腹足类作为环境监测指示种时应考虑栖息地食物丰度和饵料类型等的影响.方斑东风螺高密度工厂化养殖中应注意合理投饵并定期监测海水Cd浓度.An indoor exposure experiment with juvenile Babylonia areolata was conducted to study its survival,growth,cadmium(Cd) accumulation,metallothionein(MT) induction,and glycogen content as well as the DNA integrity of hepatopancreas tissue.The juveniles were starved or fed with mussel(Perna viridis) or clamworm(Perinereis aibuhitensis),and exposed to 50 μg·L-1 of Cd2+ for 10 weeks.Prolonged starvation and simultaneous exposure to Cd reduced the survival rate of B.areolata,and its glycogen was mobilized in great extent.Feeding with P.viridis or P.aibuhitensis helped the B.areolata to combat Cd toxicity and lessen mortality.After exposed to Cd,the damage of the DNA integrity of hepatopancreas tissue for the B.areolata fed with P.viridis or P.aibuhitensis could be recovered with time,but not for the starved B.areolata.Prolonged starvation caused tissue atrophy and led to Cd accumulation and MT increase,while feeding with P.viridis or P.aibuhitensis increased the B.areolata mass and lowered the Cd accumulation and MT level because of the tissue dilution effect.The B.areolata fed with P.viridis had better growth and lower Cd content than that fed with P.aibuhitensis.This study indicated that starvation intensified the toxicity of Cd to B.areolata,while prey type had significant effects on the growth rate of the B.areolata and indirectly affected its Cd accumulation,MT induction,and glycogen consumption.It was suggested that when using gastropods such as B.areolata as the indicator species to monitor marine environmental pollution,it would be necessary to consider the effects of habitat ecological data including food richness and prey type.Moreover,in the high-density cultivation of B.areolata in factory,rational feeding and periodic measurement of Cd concentration in seawater should be made.教育部创新团队发展计划项目(IRT0941);现代农业产业技术体系建设专项(nycytx-47);广东海洋大学校自然科学基金项目资

GENETIC CORRELATIONS TO MORPHOLOGICAL TRAITS OF SMALL ABALONE HALIOTIS DIVERSICOLOR

A total of 241 samples of small abalone (Nation's diversicolor) from 8 full-sib families of market size were used in this experiment. Shell length (X-1), shell width (X-2), shell height (X-3), apex height (X-4), body weight (Y-1), muscle weight (Y-2), and shell weight (Y-3) were measured, and the correlation coefficient matrix was calculated. The shell shape traits were used as independent variables, then body weight and muscle weight were used as dependent variable for path analysis. Path coefficients, determination coefficients, and correlation index were calculated. The results showed that correlation coefficients between each shell shape trait and body weight, muscle weight, and shell weight were all significant (P < 0.01). For the 4 shell morphological traits, body weight (Y-1) had the highest correlation coefficient with shell length (X-1), and muscle weight (Y-2) had the highest correlation coefficient with shell width (X-2). The results of high correlation index would be useful for selecting important growth-related traits in genetic breeding program of small abalone

ALLOGYOGENETIC PROGENY ARE PRODUCED FROM A HYBRID ABALONE CROSS OF FEMALE HALIOTIS DIVERSICOLOR AND MALE HALIOTIS DISCUS DISCUS

Interspecific hybrid families of female Haliotis diversicolor X male H. discus discus were produced and analyzed using amplified fragment length polymorphism (AFLP) technology to reveal the genetic makeup of F1 progenies. The survival rates of the hybrid F1 were very low, ranging from 0-0.13%. Twenty hybrid F1 from 3 families along with 3 different female parents and their common male parent were analyzed with 3 AFLP primer combinations. In total, 266 markers were detected. Genetic relationships among the progenies and the parents were evaluated by generating a similarity and genetic distance matrix. The genetic divergence between Haliotis diversicolor and Haliotis discus was at a high level, with genetic distance ranging from 1.471-1.492. The AFLP band patterns of hybrid F1 progeny were similar to those of the female parents, but were quite different from that of the male parent. The mean genetic distance between hybrid F1 and their female parents were 0.024-0.039, slightly less than that among the female parents, which indicates that the hybrid F1 shared high genetic similarity with their female parents, Haliotis diversicolor. However, 0-0.8% of total AFLP bands of each individual were found to be parental bands, and 0-3.3% were found to be nonparental bands. The possible reason for the presence of paternal-specific and nonparental bands is discussed

HERITABILITY OF GROWTH TRAITS FOR SMALL ABALONE HALIOTIS DIVERSICOLOR ESTIMATED FROM SIB MATINGS

Twelve half-sib groups and 36 full-sib groups of small abalone Haliotis diversicolor were obtained by the unbalanced nest design using artificial fertilization of 3 females by each male. Heritabilities of growth-related traits were estimated from postlarva to market size at days 10, 40, 120, 220, 320, and 420. The estimated heritabilities based on sire components for shell length and shell width were 0.15-0.37 and 0.18-0.42, respectively. Heritability estimate for shell length and shell width based on dam component were larger than those based on sire component. The results in the current study indicate that genetic improvement through selective breeding conducted on small abalone might be available and would be an efficient method to obtain a positive response to selection

KARYOLOGICAL STUDIES OF THE HYBRID LARVAE OF HALIOTIS DISVERSICOLOR SUPERTEXTA FEMALE AND HALIOTIS DISCUS DISCUS MALE

To determine the genomic composition of the interspecific hybrid between Haliotis diversicolor supertexta female and H. discus discus male at an early developmental stage, veliger larvae produced from hybrid (SJ-5 and SJ-50) and pure species crosses (SS and JJ) were sampled and analyzed using standard karyological methods and genomic in situ hybridization. In hybrid metaphase spreads, chromosomes from both parents were detected, except one metaphase, which showed the H. diversicolor supertexta haploid karyotype. The genomic composition of the hybrid was also confirmed through preliminary genomic in situ hybridization results. Many more aneuploids and chromosome fragments were found in the hybrids than those in the control pure species crosses, indicating genome instability and chromosome loss in the hybrids. In the hybrid hypodiploid metaphase spreads, two intact sets of H. diversicolor supertexta chromosomes and several H. discus discus chromosomes were detected by pairing. Spontaneous diploidization of the maternal chromosome set was shown to occur in hybrid larvae, as 2.2% heterogeneous triploid and 17.9% hypodiploids with two intact H. diversicolor supertexta chromosome sets for SJ-5. The current findings suggest that uniparental chromosome elimination along with spontaneous diploidization of maternal chromosome sets may be the reason for allogynogenesis production in H. diversicolor supertexta X H. discus discus hybridization

国外对藤壶幼体附着的研究进展

国家自然科学基金!资助项目49976034

AFLP ANALYSIS OF POPULATIONS OF HALIOTIS DISCUS HANNAI, HALIOTIS GIGANTEA, AND THEIR HYBRIDS

Amplified fragment length polymorphism (AFLP) analysis of the population genetic structure and genetic diversity of Haliotis discus hannai (D), Haliotis gigantea (G), and their reciprocal hybrids D female x G male (DG) and G female x D male (GD) was carried out in this study. A total of 479 unambiguous and highly repeatable AFLP markers, 311 of which (64.93%) were polymorphic, were obtained using 7 primer combinations. The reciprocal hybrids inherited bands from both parents, indicating that the hybrids were truly heterogeneous. The Shannon diversity index for D, G, and their reciprocal hybrid populations DG and GD was 0.169 +/- 0.188, 0.211 +/- 0.227, 0.236 +/- 0.267, and 0.231 +/- 0.242, respectively. Analysis of molecular variance revealed that 29.58% of the variance was among populations, whereas 71.42% of variance was within populations. Genetic distance was maximum (0.681) between D and G, and was minimum (0.482) between GD and G. The 4 populations were clustered into 2 major clades using the unweighted pair group method with arithmetic mean. All genetic parameters indicated that there was plentiful genetic diversity in the reciprocal hybrids of D X G. Results of this study suggest that these AFLP markers can be used in the future to enhance current breeding practices in abalone culture because of the large numbers of polymorphic markers