Zhu Tengfei, Corraze Geneviève, Plagnes-Juan Elisabeth, Quillet Edwige, Dupont-Nivet Mathilde, Skiba-Cassy Sandrine
Institut National de la Recherche Agronomique, Unité Mixte de Recherche, Joint Research Unit 1419, Nutrition Métabolisme Aquaculture, Saint Pée-sur-Nivelle, France.
Génétique Animale et Biologie Intégrative, Institut National de la Recherche Agronomique, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France.
Am J Physiol Regul Integr Comp Physiol. 2018 Jan 1;314(1):R58-R70. doi: 10.1152/ajpregu.00179.2017. Epub 2017 Sep 20.
When compared with fish meal and fish oil, plant ingredients differ not only in their protein content and amino acid and fatty acid profiles but are also devoid of cholesterol, the major component of cell membrane and precursor of several bioactive compounds. Based on these nutritional characteristics, plant-based diets can affect fish physiology and cholesterol metabolism. To investigate the mechanisms underlying cholesterol homeostasis, rainbow trout were fed from 1 g body wt for 6 mo with a totally plant-based diet (V), a marine diet (M), and a marine-restricted diet (MR), with feed intake adjusted to that of the V group. The expression of genes involved in cholesterol synthesis, esterification, excretion, bile acid synthesis, and cholesterol efflux was measured in liver. Results showed that genes involved in cholesterol synthesis were upregulated in trout fed the V diet, whereas expression of genes related to bile acid synthesis ( cyp7a1) and cholesterol elimination ( abcg8) were reduced. Feeding trout the V diet also enhanced the expression of srebp-2 while reducing that of lxrα and miR-223. Overall, these data suggested that rainbow trout coped with the altered nutritional characteristics and absence of dietary cholesterol supply by increasing cholesterol synthesis and limiting cholesterol efflux through molecular mechanisms involving at least srebp-2, lxrα, and miR-223. However, plasma and body cholesterol levels in trout fed the V diet were lower than in fish fed the M diet, raising the question of the role of cholesterol in the negative effect of plant-based diet on growth.
与鱼粉和鱼油相比，植物性成分不仅在蛋白质含量、氨基酸和脂肪酸组成方面存在差异，而且不含胆固醇，胆固醇是细胞膜的主要成分以及几种生物活性化合物的前体。基于这些营养特性，植物性日粮会影响鱼类生理和胆固醇代谢。为了研究胆固醇稳态的潜在机制，从体重1克开始，对虹鳟鱼进行为期6个月的投喂，分别采用全植物性日粮（V）、海洋性日粮（M）和海洋性限制日粮（MR），并将饲料摄入量调整至与V组相同。测定肝脏中参与胆固醇合成、酯化、排泄、胆汁酸合成和胆固醇流出的基因表达。结果表明，投喂V日粮的虹鳟鱼中参与胆固醇合成的基因上调，而与胆汁酸合成（cyp7a1）和胆固醇消除（abcg8）相关的基因表达降低。给虹鳟鱼投喂V日粮还增强了srebp-2的表达，同时降低了lxrα和miR-223的表达。总体而言，这些数据表明，虹鳟鱼通过增加胆固醇合成并通过至少涉及srebp-2、lxrα和miR-223的分子机制限制胆固醇流出，来应对营养特性的改变和日粮胆固醇供应的缺乏。然而，投喂V日粮的虹鳟鱼的血浆和体内胆固醇水平低于投喂M日粮的鱼，这就引发了关于胆固醇在植物性日粮对生长的负面影响中所起作用的问题。
