Seaweed phytosterols are associated with potential health benefits, affording them and the seaweeds that produce them commercial interest. However, little is known about how their production is affected by the cultivation environment, limiting the efficiency with which these compounds can be exploited. Therefore, we performed a pilot study on the effect of nutrient availability and light stress on the sterol content of Saccharina latissima, a rapid growing brown alga of increasing interest in western mariculture. Individuals of S. latissima were subjected to a nutrient-replete and nutrient-depleted regime for 5 weeks, followed by the introduction of light-limited and light-saturated conditions in the sixth week; sampling occurred each week. No significant inter-treatment differences were found in the sterol content in week 1–5. However, significant intra-treatment differences were found in weeks 3–5 regardless of nutrient treatment, wherein the fucosterol, 24-methylenecholesterol, and squalene contents of both treatment groups were found to correlate inversely with photosynthetic performance. Factorial treatment of differential nutrient availability and light stress resulted in marked differences between the sterol content of all groups in week 6. Here, squalene and cycloartenol increased in concentration with increasing irradiance regardless of nutrient treatment. Concentrations of all other sterolic components increased with increasing irradiance and low nutrient conditions while decreasing or remaining unchanged with increasing irradiance and high nutrient conditions. Our data shows that within our cultivation conditions and time frame, the sterol content of S. latissima is unaffected by nutrient availability alone but changes with combined alterations in irradiance and nutrient availability.

Graphical abstract

中文翻译：

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营养物质有效性和光照强度对Saccharina latissima（Laminariales，Phaeophyceae）固醇含量的影响

海藻植物固醇与潜在的健康益处相关，使它们和产生它们的海藻具有商业价值。然而，关于它们的生产如何受到栽培环境的影响却知之甚少，从而限制了这些化合物的开发效率。因此，我们进行了一项营养丰富和轻度胁迫对Saccharina latissima固醇含量影响的试点研究，Saccharina latissima是一种快速生长的褐藻，对西方海水养殖越来越感兴趣。S. latissima的个体在5周内接受营养丰富和营养贫乏的治疗，然后在第六周引入光限制和光饱和条件；每周进行一次抽样。第1-5周的固醇含量没有明显的治疗间差异。然而，无论采用何种营养处理，在第3-5周都发现了明显的处理内差异，其中两个处理组的岩藻糖醇，24-亚甲基胆固醇和角鲨烯含量均与光合性能呈负相关。差异养分利用率和轻度胁迫的因素处理导致第6周所有组的固醇含量之间存在显着差异。此处，无论采用何种养分处理，角鲨烯和环烯醇的浓度均随辐照度的增加而增加。随着辐照度和低养分条件的增加，所有其他固醇成分的浓度增加，而随着辐照度和高养分条件的减少或保持不变。我们的数据表明，在我们的栽培条件和时间框架内，latissima链球菌不受养分利用率的影响，但随着辐照度和养分利用率的综合变化而变化。

图形概要