Institute of Life Sciences, Université catholique de Louvain, Place Croix du Sud 2/L7.05.08, B-1348 Louvain-la-Neuve, Belgium; Laboratory of Environmental Toxicology and Aquatic Ecology, Environmental Toxicology Unit, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
Laboratory of Environmental Toxicology and Aquatic Ecology, Environmental Toxicology Unit, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
Chemosphere. 2018 Aug;205:328-338. doi: 10.1016/j.chemosphere.2018.04.091. Epub 2018 Apr 17.
Long chain polyunsaturated fatty acids (LC-PUFAs) such as eicosapentaenoic acid (EPA, 20:5n-3) affect zooplankton fitness and ability to cope with environmental stressors. However, the impact of LC-PUFAs on zooplankton sensitivity to chemical stressors is unknown. Here, we aimed to document the interaction between EPA and cadmium (Cd), as model chemical stressor, in Daphnia magna. A life-history experiment was performed in which daphnid neonates were raised into adulthood on three diets of different lipid composition: (i) algae mix; (ii) algae mix supplemented with control liposomes; (iii) algae mix supplemented with liposomes containing EPA. Juveniles (3rd, 4th and 5th brood) released by daphnids during this life-history experiment were sampled, challenged with Cd during 48 h and their immobility was assessed. At the end of this life-history experiment, another immobilisation test was performed with adults from each treatment. Daphnids absorbed, incorporated and transferred ingested EPA to their offspring. Liposome feeding increased adult tolerance to Cd. The presence of EPA in liposomes did not increase adult tolerance to Cd. Offspring's tolerance to Cd was influenced by the brood number and the maternal diet. It was positively correlated with the PUFA level in body neutral lipids, especially alpha-linolenic acid (ALA, 18:3n-3) and negatively correlated with the saturated fatty acid level in body neutral lipids, especially stearic acid (18:0). Overall, these results emphasize the importance of dietary lipids and maternal transfer of body lipids in D. magna sensitivity to Cd and highlight the need to take into account these parameters in ecotoxicological studies and risk assessment.
长链多不饱和脂肪酸（LC-PUFAs），如二十碳五烯酸（EPA，20:5n-3），会影响浮游动物的适应性和应对环境胁迫的能力。然而，LC-PUFAs 对浮游动物对化学胁迫敏感性的影响尚不清楚。在这里，我们旨在记录 EPA 与镉（Cd）作为模型化学胁迫物在大型溞（Daphnia magna）中的相互作用。进行了一项生活史实验，其中将大型溞的幼体饲养至成年，幼体饲养在三种不同脂质组成的饮食中：（i）藻类混合物；（ii）藻类混合物补充对照脂质体；（iii）藻类混合物补充含有 EPA 的脂质体。在这个生活史实验中，由大型溞释放的幼体（第 3、4 和 5 代）被取样，在 48 小时内用 Cd 进行挑战，并评估其不活动状态。在这个生活史实验结束时，对每个处理的成年个体进行另一次固定化测试。大型溞吸收、结合并将摄入的 EPA 转移到其后代体内。脂质体喂养增加了成体对 Cd 的耐受性。脂质体中 EPA 的存在并没有增加成体对 Cd 的耐受性。后代对 Cd 的耐受性受到胎次和母体饮食的影响。它与体内中性脂类中的多不饱和脂肪酸（PUFA）水平呈正相关，特别是α-亚麻酸（ALA，18:3n-3），与体内中性脂类中的饱和脂肪酸水平呈负相关，特别是硬脂酸（18:0）。总的来说，这些结果强调了饮食脂质和母体体脂传递在大型溞对 Cd 的敏感性中的重要性，并强调在生态毒理学研究和风险评估中需要考虑这些参数。
