BACKGROUND The finite marine resources make it difficult for us to obtain enough fish oil (FO) used in aquatic feeds. Another sustainable ingredients should be found to substitute FO. The effects of replacing FO with vegetable oil have been studied in a variety of crustaceans, but most studies have focused on the phenotypic effects. Little is known about the mechanisms of the effects. METHODS To understand the molecular responses during the replacement of FO in Eriocheir sinensis, we investigated the effects of feeding FO or linseed oil (LO) on growth performance, digestive enzyme activity, fatty acid composition and protein expression in E. sinensis. Twenty-four juvenile crabs were fed diets containing FO or LO for 112 days. Weight, carapace length and width were recorded. Fatty acid composition of the diets and the hepatopancreas and protein expression in the hepatopancreas were analyzed. RESULTS Growth performance and molting interval were unchanged by diet. Crabs fed FO and LO had same activity of lipase and amylase, but comparing with crabs fed LO, crabs fed FO had higher trypsin activity and lower pepsin activity. Hepatopancreas fatty acid composition changed to reflect the fatty acid composition of the diets. In total, 194 proteins were differentially expressed in the hepatopancreas between the diets. Expression of heat shock proteins was higher in crabs fed LO. Expression of fatty acid synthase, long-chain fatty acid transport protein 4, acyl-CoA delta-9 desaturase, and fatty acid-binding protein 1, was higher in crabs fed FO. CONCLUSIONS The substitution of FO with LO didn't have any effects on the growth and molting of mitten crab, but could significantly decrease the ability of mitten crab to cope with stress. The high content of HUFAs in the hepatopancreas of mitten crab fed FO is due to the high abundance of the proteins relative to the transport of the HUFAs. These findings provide a reason of the high content of EPA and DHA in crabs fed with FO, and provide new information for the replacement of FO in diets of mitten crab.

中文翻译：

---

亚麻籽油完全替代鱼油对中华绒螯蟹 (Eriocheir sinensis) 生长、脂肪酸组成和蛋白质表达的影响。

背景技术有限的海洋资源使我们难以获得足够的鱼油（FO）用于水产饲料。应该找到另一种可持续的成分来替代 FO。已经在多种甲壳类动物中研究了用植物油代替 FO 的效果，但大多数研究都集中在表型效应上。人们对这些影响的机制知之甚少。方法 为了解中华绒螯蟹 FO 替代过程中的分子反应，我们研究了饲喂 FO 或亚麻籽油 (LO) 对中华绒螯蟹生长性能、消化酶活性、脂肪酸组成和蛋白质表达的影响。24 只幼蟹被喂食含有 FO 或 LO 的饲料 112 天。记录重量、甲壳长度和宽度。分析日粮脂肪酸组成及肝胰腺和肝胰腺中蛋白质的表达。结果 日粮对生长性能和蜕皮间隔没有影响。喂食FO和LO的螃蟹脂肪酶和淀粉酶活性相同，但与喂食LO的螃蟹相比，喂食FO的螃蟹胰蛋白酶活性较高，胃蛋白酶活性较低。肝胰腺脂肪酸组成发生变化以反映饮食中的脂肪酸组成。总共有 194 种蛋白质在不同饮食之间的肝胰腺中差异表达。喂食 LO 的螃蟹中热休克蛋白的表达较高。脂肪酸合酶、长链脂肪酸转运蛋白 4、酰基辅酶 A delta-9 去饱和酶和脂肪酸结合蛋白 1 的表达在喂食 FO 的螃蟹中更高。结论 用 LO 代替 FO 没有 对绒螯蟹的生长和蜕皮没有任何影响，但会显着降低绒螯蟹应对压力的能力。喂食 FO 的绒螯蟹肝胰腺中 HUFA 的高含量是由于相对于 HUFA 的运输而言蛋白质的高丰度。这些发现为喂食FO的螃蟹中EPA和DHA含量高提供了一个原因，并为在绒螯蟹日粮中替代FO提供了新的信息。