Reproductive toxicity of dietary zinc to Daphnia magna
Reproductive toxicity of dietary zinc to Daphnia magna
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DOI：
10.1016/j.aquatox.2004.09.008
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发表时间：
2004-12-10
影响因子：
4.5
通讯作者：
Janssen, CR
中科院分区：
文献类型：
--
作者：
De Schamphelaere, KAC;Canli, M;Janssen, CR
对淡水中金属的监管评估主要基于溶解的金属浓度，假设毒性仅由水生金属引起。很少有人注意到饮食中的金属对淡水无脊椎动物的毒性。本文研究了饲料锌对大型蚤的慢性毒性。将绿色假基氏藻暴露于对照和三种溶解锌浓度（即23、28和6 1 μ g L-1）下64 h，导致藻体内锌负荷分别为130、200、320和490 μ g（-1）干重。这些藻类被用作食物源，在慢性，21天的生物测定与D。Magna在不添加溶解的锌的测试介质中。所有处理均未对杜氏食蚁兽的摄食率和体细胞生长产生影响。magna.与此相反，一个显着的40%减少总繁殖（每成人的青少年数量），观察到在28和61杯L-1的治疗。第一次育雏的时间没有受到影响，而平均育雏大小和繁殖父母水蚤的分数从第二次育雏开始减少，这些减少的幅度增加，随后的育雏。生殖能力的降低伴随着61 μ g L-1处理中锌积累的升高，这表明总的身体负担不是饮食锌毒性的良好指标。总的来说，我们的数据表明，膳食锌专门针对生殖D。通过在特定的靶位点，可能是卵黄蛋白原合成或加工发生的细胞或组织中积累，此外，我们的数据表明，饮食暴露途径的潜在重要性应在锌的监管评估中仔细考虑和解释。(C)2004 Elsevier B. V.保留所有权利。
Regulatory assessments of metals in freshwaters are mostly based on dissolved metal concentrations, assuming that toxicity is caused by waterborne metal only. Little attention has been directed to the toxicity of dietary metals to freshwater invertebrates. In this study the chronic toxicity of dietary zinc to Daphnia magna was investigated. The green alga Pseudokirchneriella subcapitata was exposed for 64 h to a control and three dissolved zinc concentrations, i.e. 23, 28 and 6 1 mug L-1, resulting in internal zinc burdens in the algae of 130, 200, 320 and 490 mug g(-1) dry weight, respectively. These algae were used as a food Source in chronic, 21-day bioassays with D. magna in a test medium to which no dissolved zinc was added. None of the treatments resulted in effects on feeding rates or somatic growth of D. magna. In contrast, a significant 40% decrease of total reproduction (number of juveniles per adult) was observed in the 28 and 61 mug L-1 treatments. Timeto first brood was not affected, whereas the mean brood size and the fraction of reproducing parent daphnids were reduced from the second brood onwards and the magnitude of these reductions increased with each subsequent brood. The reduced reproduction was accompanied with an elevated zinc accumulation in the 61 mug L-1 treatment only, suggesting that total body burden is no good indicator of dietary zinc toxicity. Overall Our data suggest that dietary zinc specifically targets reproduction in D. magna through accumulation in particular target sites, possibly cells or tissues where vitellogenin synthesis or processing occur. Further, our data illustrate that the potential importance of the dietary exposure route Should be carefully considered and interpreted in regulatory assessments of zinc. (C) 2004 Elsevier B.V. All rights reserved.