The study revealed species- and stage-specific differences in lipid accumulation of the dominant Antarctic copepods, the primarily herbivorous Calanoides acutus (copepodite stage V (CV), females) and the more omnivorous Calanus propinquus (females) storing wax esters and triacylglycerols, respectively, which were collected in summer (end of December). Feeding carbon-labelled diatoms to these copepods, 13 C elucidated assimilation and turnover rates of copepod total lipids as well as specific fatty acids and alcohols. The 13 C incorporation was monitored by compound-specific stable isotope analysis (CSIA). CV stages of C. acutus exhibited an intense total lipid turnover and 55% of total lipids were labelled after 9 days of feeding. By contrast, total lipid assimilation of female C. acutus and C. propinquus was lower with 29% and 32%, respectively. The major dietary fatty acids 16:0, 16:1(n − 7) and 20:5(n − 3) had high turnover rates in all specimens. In C. acutus CV, the high rates of the de novo synthesized long-chain monounsaturated fatty acids and alcohols 20:1(n − 9) and 22:1(n − 11) indicate intense lipid deposition, whereas these rates were low in females. The differences in lipid assimilation and turnover clearly show that the copepod species exhibit a high variability and plasticity to adapt their lipid production to their various life phases. This article is part of the theme issue ‘The next horizons for lipids as ‘trophic biomarkers': evidence and significance of consumer modification of dietary fatty acids'.

中文翻译：

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喂食富含 13 C 的硅藻的南极优势桡足类中脂质化合物的同化和周转率

该研究揭示了主要食草动物南极桡足类动物脂质积累的物种和阶段特异性差异尖角胡蝽（桡足第五阶段（CV），雌性）和更杂食的哲水蚤（雌性）分别储存蜡酯和三酰甘油，这些是在夏季（12月底）收集的。给这些桡足类动物喂食碳标记的硅藻，13C 阐明了桡足类总脂质以及特定脂肪酸和醇的同化和周转率。这13通过化合物特异性稳定同位素分析 (CSIA) 监测 C 的掺入。CV阶段锐角线虫表现出强烈的总脂质周转率，喂养 9 天后 55% 的总脂质被标记。相比之下，女性的总脂质同化锐角线虫和C. propinquus分别较低，为 29% 和 32%。主要膳食脂肪酸 16:0、16:1(n − 7) 和 20:5(n − 3) 在所有样本中均具有较高的周转率。在锐角线虫CV，从头合成的长链单不饱和脂肪酸和醇 20:1(n − 9) 和 22:1(n − 11) 的高比率表明脂质沉积强烈，而女性中这些比率较低。脂质同化和周转的差异清楚地表明，桡足类物种表现出高度的可变性和可塑性，以使其脂质生产适应不同的生命阶段。本文是主题“脂质作为‘营养生物标志物’的下一个前景：消费者改变膳食脂肪酸的证据和意义”的一部分。