Selenium(Se) is a biological essential trace element that affects the growth and health of fish. The present study aimed to explore the dietary Se requirement of triploid rainbow trout using Se-yeast supplement. The levels of Se added to the basal diet were 0(Se₀), 0.1(Se_0.1), 0.3(Se_0.3), 0.5(Se_0.5), 1.0(Se_1.0), 4.0(Se_4.0) and 16.0(Se_16.0) mg Se/kg diet respectively. Results showed that the fish fed Se_4.0 diet had significantly higher weight gain and lower oxidative stress compared with the fish fed Se_16.0 and Se₀ diets. The optimal dietary Se requirement of triploid rainbow trout was 3.53 mg/kg based on broken-line regression of growth performance. Dietary Se supplementation significantly increased the expression level of selenoprotein genes both in liver (GPX1a, GPX1b1, GPX1b2, SelK, SelP, SelT1, SelT2, SelWl, TrxR3a, SelU) and in muscle (GPX1a, GPX1b2, SelK, SelP, SelU, SelWl, TrxR3b, SelN, MsrB1Al). The minimum dietary Se level was 2.19 or 1.28 mg/kg when the mRNA level of all these selenoproteins reached a plateau in muscle or liver respectively. In conclusion, based on broken-line regression of growth performance and sigmoidal regression of selenoprotein genes expression in muscle and liver, dietary Se requirement of triploid rainbow trout was 3.53, 2.19 and 1.28 mg/kg respectively.

中文翻译：

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三倍体虹鳟鱼 (Oncorhynchus mykiss) 基于硒酵母补充剂的日粮硒需求

硒（Se）是一种影响鱼类生长和健康的生物必需微量元素。本研究旨在探讨使用硒酵母补充剂对三倍体虹鳟鱼的膳食硒需求。添加到基础日粮中的硒水平为0(Se ₀ )、0.1(Se _0.1 )、0.3(Se _0.3 )、0.5(Se _0.5 )、1.0(Se _1.0 )、4.0(Se _4.0 )和16.0(Se _16.0 ) 分别为 mg Se/kg 饮食。结果表明，与喂食 Se _16.0和 Se _{0的鱼相比，喂食 Se 4.0}饲料的鱼的体重增加显着更高，氧化应激更低饮食。基于生长性能的折线回归，三倍体​​虹鳟鱼的最佳日粮硒需求量为3.53 mg/kg。膳食硒补充剂显着增加了肝脏（GPX1a、GPX1b1、GPX1b2、SelK、SelP、SelT1、SelT2、SelWl、TrxR3a、SelU）和肌肉（GPX1a、GPX1b2、SelK、SelP、SelU、SelWl ）中硒蛋白基因的表达水平, TrxR3b , SelN, MsrB1Al )。当所有这些硒蛋白的 mRNA 水平分别在肌肉或肝脏中达到一个平台时，最低膳食硒水平为 2.19 或 1.28 mg/kg。总之，基于生长性能的折线回归和肌肉和肝脏中硒蛋白基因表达的S形回归，三倍体​​虹鳟鱼的日粮硒需求量分别为3.53、2.19和1.28 mg/kg。