Biomar AS, Havnegata 9, 7010, Trondheim, Norway.
Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway.
BMC Vet Res. 2020 Jan 31;16(1):32. doi: 10.1186/s12917-020-2252-7.
Various intestinal morphological alterations have been reported in cultured fish fed diets with high contents of plant ingredients. Since 2000, salmon farmers have reported symptoms indicating an intestinal problem, which we suggest calling lipid malabsorption syndrome (LMS), characterized by pale and foamy appearance of the enterocytes of the pyloric caeca, the result of lipid accumulation. The objective of the present study was to investigate if insufficient dietary choline may be a key component in development of the LMS.
The results showed that Atlantic salmon (Salmo salar), average weight 362 g, fed a plant based diet for 79 days developed signs of LMS. In fish fed a similar diet supplemented with 0.4% choline chloride no signs of LMS were seen. The relative weight of the pyloric caeca was 40% lower, reflecting 65% less triacylglycerol content and histologically normal gut mucosa. Choline supplementation further increased specific fish growth by 18%. The concomitant alterations in intestinal gene expression related to phosphatidylcholine synthesis (chk and pcyt1a), cholesterol transport (abcg5 and npc1l1), lipid metabolism and transport (mgat2a and fabp2) and lipoprotein formation (apoA1 and apoAIV) confirmed the importance of choline in lipid turnover in the intestine and its ability to prevent LMS. Another important observation was the apparent correlation between plin2 expression and degree of enterocyte hyper-vacuolation observed in the current study, which suggests that plin2 may serve as a marker for intestinal lipid accumulation and steatosis in fish. Future research should be conducted to strengthen the knowledge of choline's critical role in lipid transport, phospholipid synthesis and lipoprotein secretion to improve formulations of plant based diets for larger fish and to prevent LMS.
Choline prevents excessive lipid accumulation in the proximal intestine and is essential for Atlantic salmon in seawater.
在食用含有高植物成分的饮食的养殖鱼类中，已经报道了各种肠道形态改变。自 2000 年以来，三文鱼养殖户报告了表明肠道问题的症状，我们建议将其称为脂类吸收不良综合征（LMS），其特征是幽门盲囊的肠细胞呈现苍白和泡沫状，这是脂类积累的结果。本研究的目的是研究膳食中胆碱不足是否是 LMS 发展的关键因素。
结果表明，平均体重为 362 克的大西洋三文鱼（Salmo salar）在食用植物性饮食 79 天后出现 LMS 症状。在食用类似饮食并补充 0.4%氯化胆碱的鱼中，没有观察到 LMS 迹象。幽门盲囊的相对重量低 40%，反映出三酰甘油含量低 65%，肠道黏膜组织学正常。胆碱补充剂进一步使特定鱼类生长增加了 18%。与磷脂酰胆碱合成（chk 和 pcyt1a）、胆固醇转运（abcg5 和 npc1l1）、脂质代谢和转运（mgat2a 和 fabp2）和脂蛋白形成（apoA1 和 apoAIV）相关的肠道基因表达的伴随改变证实了胆碱在肠道脂质周转中的重要性及其预防 LMS 的能力。另一个重要的观察结果是，在当前研究中观察到的plin2 表达与肠细胞空泡化程度之间的明显相关性，这表明 plin2 可能作为鱼类肠道脂质积累和脂肪变性的标志物。未来的研究应加强对胆碱在脂质转运、磷脂合成和脂蛋白分泌中的关键作用的认识，以改善植物性饮食配方，用于养殖更大的鱼类，并预防 LMS。
胆碱可防止在近端肠道中发生过量的脂质积累，对在海水中的大西洋三文鱼来说是必不可少的。
