Salmonines in the Baltic Sea and North American lakes suffer from thiamine (vitamin B1) deficiency, which is connected to an abundant lipid-rich diet containing substantial amounts of polyunsaturated fatty acids (PUFAs). In the Baltic region, this is known as the M74 syndrome. It affects both adult salmon (Salmo salar) and especially their offspring, impairing recruitment. However, very little is known about the thiamine and lipid metabolism of salmon during feeding and spawning migrations in the Baltic Sea. In this study, salmon females were sampled along the spawning run from the southern Baltic Proper in four locations at sea and finally at spawning in a river at the Bothnian Bay in a year with insignificant M74 mortality. Changes in concentrations of thiamine and its components in muscle, ovaries, and the liver and other biochemical indices potentially relating to lipid and fatty acid metabolism were investigated. The results provide further evidence of the role of peroxidation of PUFAs in eliciting thiamine deficiency in salmon: During the entire spawning run, the muscle total lipid content decreased by 50%, palmitic acid (16:0) by 62%, and docosahexaenoic acid (DHA, 22:6n-3) by 45%. The concentration of total thiamine decreased significantly until the spawning in the liver and ovaries, 66 and 70% respectively. In the muscle, the proportion of thiamine pyrophosphate of total thiamine increased with the use of muscular lipid stores. There was no trend in the concentration of total carotenoids during the spawning run. The doubling of the concentration of hepatic malondialdehyde indicated peroxidation of PUFAs, and the mobilisation of body lipids suppressed the activity of glucose-6-phosphate dehydrogenase, as consumed dietary lipids would also have done.

中文翻译：

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产卵期和产卵前禁食期间波罗的海大西洋鲑鱼（Salmo salar）中硫胺素浓度，脂肪酸组成和其他一些与脂质相关的生化指标的变化

波罗的海和北美湖泊中的鲑鱼患有硫胺素（维生素B1）缺乏症，其与含有大量多不饱和脂肪酸（PUFA）的丰富的富含脂质的饮食有关。在波罗的海地区，这被称为M74综合征。它会影响成年鲑（Salmo salar），尤其是其后代，从而影响募集。但是，关于波罗的海鲑鱼在觅食和产卵过程中硫胺素和脂质代谢的了解甚少。在这项研究中，从波罗的海南部南部的四个产卵地点的产卵场取样鲑鱼，最后一年在博特尼安湾的一条河流产卵，M74的死亡率微不足道。肌肉，卵巢中硫胺素及其成分的浓度变化 并研究了可能与脂质和脂肪酸代谢有关的肝脏和其他生化指标。结果进一步证明了PUFA的过氧化作用会引起鲑鱼硫胺素缺乏：在整个产卵过程中，肌肉总脂质含量降低了50％，棕榈酸（16：0）降低了62％，二十二碳六烯酸（ DHA，22：6n-3）降低了45％。直到肝脏和卵巢中产卵的总硫胺素浓度均显着下降，分别为66％和70％。在肌肉中，硫胺素焦磷酸硫胺在总硫胺素中的比例随着肌肉脂质存储的使用而增加。产卵过程中总类胡萝卜素的浓度没有变化的趋势。肝丙二醛浓度加倍表明PUFAs过氧化，