Biomar AS, Trondheim, Norway.
Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway.
Br J Nutr. 2020 May 28;123(10):1081-1093. doi: 10.1017/S0007114520000434. Epub 2020 Feb 10.
Foamy, whitish appearance of the pyloric caeca, reflecting elevated lipid content, histologically visible as hypervacuolation, is frequently observed in Atlantic salmon fed high-plant diets. Lipid malabsorption syndrome (LMS) is suggested as term for the phenomenon. Earlier studies have shown that insufficient supply of phospholipids may cause similar symptoms. The objective of the present study was to strengthen knowledge on the role of choline, the key component of phosphatidylcholine, in development of LMS as well as finding the dietary required choline level in Atlantic salmon. A regression design was chosen to be able to estimate the dietary requirement level of choline, if found essential for the prevention of LMS. Atlantic salmon (456 g) were fed diets supplemented with 0, 392, 785, 1177, 1569, 1962, 2354, 2746 and 3139 mg/kg choline chloride. Fish fed the lowest-choline diet had pyloric caeca with whitish foamy surface, elevated relative weight, and the enterocytes were hypervacuolated. These characteristics diminished with increasing choline level and levelled off at levels of 2850, 3593 and 2310 mg/kg, respectively. The concomitant alterations in expression of genes related to phosphatidylcholine synthesis, cholesterol biosynthesis, lipid transport and storage confirmed the importance of choline in lipid turnover in the intestine and ability to prevent LMS. Based on the observations of the present study, the lowest level of choline which prevents LMS and intestinal lipid hypervacuolation in post-smolt Atlantic salmon is 3·4 g/kg. However, the optimal level most likely depends on the feed intake and dietary lipid level.
幽门盲囊呈泡沫状、灰白色外观，反映脂质含量升高，组织学上可见空泡化过度，这在摄食高植物性饲料的大西洋鲑中经常观察到。脂质吸收不良综合征（LMS）被认为是这种现象的术语。早期研究表明，磷脂供应不足可能导致类似的症状。本研究的目的是加强对胆碱（磷脂酰胆碱的关键成分）在 LMS 发展中的作用的认识，并确定大西洋鲑中 LMS 所需的胆碱饮食水平。选择回归设计是为了能够估计胆碱的饮食需求水平，如果发现胆碱对预防 LMS 是必需的。用补充有 0、392、785、1177、1569、1962、2354、2746 和 3139 mg/kg 氯化胆碱的饲料喂养大西洋鲑（456 g）。摄食最低胆碱饲料的鱼的幽门盲囊表面呈灰白色泡沫状，相对重量增加，肠细胞有空泡化过度。这些特征随着胆碱水平的增加而减少，在 2850、3593 和 2310 mg/kg 时分别趋于平稳。与磷脂酰胆碱合成、胆固醇生物合成、脂质转运和储存相关的基因表达的同时改变证实了胆碱在肠道脂质周转和预防 LMS 中的重要性。基于本研究的观察结果，预防 LMS 和使幼大西洋鲑肠道脂质空泡化过度的最低胆碱水平为 3·4 g/kg。然而，最佳水平很可能取决于饲料摄入量和饮食脂质水平。
