Bile is a yellow‐green liquid produced in the liver from cholesterol and stored in the gallbladder of vertebrates. Bile improves the efficacy of lipid digestion by acting as an emulsifier and is essential in activating bile salt lipase, an enzyme that has broad substrate specificity. Bile improves the absorption of lipid soluble nutrients while also facilitating the excretion of cholesterol and toxic metabolites, particularly bilirubin. Dietary fishmeal alternatives often disturb bile acid status in fish resulting in either increased excretion/decreased intestinal reabsorption and/or decreased bile acid synthesis. Saponins and high molecular mass proteins are believed to contribute to altered bile acid status, which may reduce fish productivity. This situation can worsen with increased incorporations of plant‐based proteins in aquafeeds, but also may be mitigated by processing of fishmeal alternatives as well as the dietary inclusion of some bile acids/salts. This area of research will likely increase due to the roles dietary bile acids/salts can have on protecting digestive organs and improving nutrient utilization. This, however, depends on the bile type, level and fish species. This review discusses these aspects in regard to fish nutrition to help increase the inclusion of dietary fishmeal alternatives and thus enhance aquaculture sustainability.

中文翻译：

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鱼中的胆汁酸代谢：鱼粉替代品引起的干扰以及饮食中胆汁中夹杂物的某些缓解作用

胆汁是一种黄绿色液体，在肝脏中由胆固醇产生，并储存在脊椎动物的胆囊中。胆汁通过充当乳化剂来提高脂质消化的功效，并且在激活胆汁盐脂肪酶（一种具有广泛的底物特异性的酶）中至关重要。胆汁改善了脂溶性营养物的吸收，同时也促进了胆固醇和有毒代谢产物，特别是胆红素的排泄。膳食鱼粉替代品通常会扰乱鱼中的胆汁酸状态，从而导致排泄增加/肠道重吸收减少和/或胆汁酸合成减少。皂苷和高分子蛋白被认为会改变胆汁酸状态，这可能会降低鱼类的生产力。随着水产饲料中植物性蛋白质掺入量的增加，这种情况可能会恶化，但也可以通过加工鱼粉替代品以及在饮食中添加一些胆汁酸/盐来缓解。由于饮食中的胆汁酸/盐在保护消化器官和提高养分利用率方面的作用，这一研究领域可能会增加。但是，这取决于胆汁的类型，水平和鱼类。这篇综述讨论了与鱼类营养有关的这些方面，以帮助增加膳食鱼粉替代品的纳入，从而提高水产养殖的可持续性。水平和鱼类种类。这篇综述讨论了与鱼类营养有关的这些方面，以帮助增加膳食鱼粉替代品的纳入，从而提高水产养殖的可持续性。水平和鱼类种类。这篇综述讨论了与鱼类营养有关的这些方面，以帮助增加膳食鱼粉替代品的纳入，从而提高水产养殖的可持续性。