Wildlife and Fisheries Conservation Center, Department of Natural Resources and the Environment and Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, CT, 06269, USA; Department of Social and Preventive Medicine, Laval University, Quebec City, QC, G1V 0A6, Canada.
Department of Biosciences, Arctic Research Centre, Aarhus University, Roskilde, DK-4000, Denmark.
Environ Res. 2019 Oct;177:108602. doi: 10.1016/j.envres.2019.108602. Epub 2019 Jul 22.
We quantified blubber concentrations of vitamins A (retinol) and E (α-tocopherol) and evaluated associations with persistent organic pollutants (ΣPOPs) in 14 highly-contaminated killer whales (Orcinus orca) sampled in Greenland from 2012 to 2014. We considered the influence of blubber depth, sex/age class and diet (based on biomass % of major fatty acids) in these relationships. Blubber concentrations of vitamin A averaged 34.1 ± 4.7 μg g wet weight (ww) and vitamin E averaged 35.6 ± 4.4 μg g ww. Although overall vitamin A concentrations did not vary between inner (closer to the muscle) and outer (closer to the skin) blubber layer or between sub-adults and adult females, concentrations in the outer layer of sub-adults were lower compared to the outer layer of adult females (p = 0.03). Outer layer may therefore reflect age accumulation of vitamin A, while in the more active inner layer, age effects might be masked by metabolic needs such as lactation. Neither diet nor ΣPOPs affected vitamin A variation, suggesting this vitamin is highly regulated in the body. Given the high exposures in these killer whales, vitamin A might not be a sensitive biomarker for POPs adverse effects. Vitamin E concentrations were significantly higher in inner compared to outer layer (p < 0.001), likely associated with blubber composition, suggesting that biopsies may not fully represent vitamin E concentrations in blubber. Age-accumulation of vitamin E also occurred with higher concentrations in adult females compared to sub-adults, independent of blubber depth (p < 0.01). Diet, ΣPOPs, and an interaction between these two variables significantly affected vitamin E variation in inner blubber, explaining 91% of this variation. The negative relationship between ΣPOPs (especially Σdichlorodiphenyltrichloroethane (DDT) and Σchlordanes in outer layers) and vitamin E was observed only in killer whales with a diet poorer in polyunsaturated fatty acids, suggested that killer whales feeding more consistently on marine mammals in Arctic environments over a fish-based diet, may be at higher risk of POP-induced disruption in vitamin E homeostasis. Considering diet is therefore important to understand the potential effects of elevated contaminant exposures on levels of certain essential nutrients, i.e., vitamin E, in killer whales.
我们量化了 14 头在格陵兰岛 2012 年至 2014 年期间采样的高度污染的虎鲸（Orcinus orca）的脂肪中维生素 A（视黄醇）和 E（α-生育酚）的浓度，并评估了它们与持久性有机污染物（ΣPOPs）的关联。我们考虑了脂肪厚度、性别/年龄类和饮食（基于主要脂肪酸的生物量%）对这些关系的影响。维生素 A 的平均浓度为 34.1±4.7μg/g 湿重（ww），维生素 E 的平均浓度为 35.6±4.4μg/g ww。尽管总体上维生素 A 浓度在内层（靠近肌肉）和外层（靠近皮肤）脂肪层之间或亚成体和成年雌性之间没有差异，但亚成体的外层浓度低于成年雌性的外层浓度（p=0.03）。因此，外层可能反映了维生素 A 的年龄积累，而在更活跃的内层，代谢需求（如哺乳期）可能掩盖了年龄的影响。饮食和ΣPOPs 都没有影响维生素 A 的变化，这表明这种维生素在体内受到高度调节。鉴于这些虎鲸的高暴露量，维生素 A 可能不是 POPs 不良影响的敏感生物标志物。内层的维生素 E 浓度明显高于外层（p<0.001），这可能与脂肪组成有关，这表明活检可能无法完全代表脂肪中的维生素 E 浓度。维生素 E 的年龄积累也与成年雌性的浓度高于亚成体有关，与脂肪厚度无关（p<0.01）。饮食、ΣPOPs 以及这两个变量之间的相互作用显著影响了内层脂肪中维生素 E 的变化，解释了 91%的变化。只有在饮食中多不饱和脂肪酸较少的虎鲸中，外层的ΣPOPs（尤其是Σ二氯二苯三氯乙烷（DDT）和Σ氯丹）与维生素 E 之间才存在负相关关系，这表明在北极环境中以海洋哺乳动物为主要食物来源而不是以鱼类为主要食物来源的虎鲸，可能面临更高的因 POP 引起的维生素 E 稳态破坏的风险。因此，考虑饮食对于理解升高的污染物暴露对某些必需营养素（即维生素 E）水平的潜在影响是很重要的。
