The current NRC dietary selenium (Se) requirement (0.15 mg/kg) of broilers is primarily based on growth performance data reported in 1986. Our study aimed to determine optimal dietary Se levels of broilers fed a practical corn-soybean meal diet for the full expression of selenoproteins in various tissues. A total of 384 one-d-old male broilers (n = 8 replicates/diet) were fed a basal corn-soybean meal diet or the basal diet supplemented with 0.1, 0.2, 0.3, 0.4 or 0.5 mg Se/kg in the form of Na₂SeO₃ for 21 d. Regression analysis was conducted to evaluate the optimal dietary Se levels using broken-line, quadratic or asymptotic models. The activity of glutathione peroxidase (GPX) in the plasma, liver, kidney and pancreas, iodothyronine deiodinase (DIO) in the plasma, liver and pancreas, and thioredoxin reductase (Txnrd) in the liver and pancreas, the mRNA levels of Gpx1, Gpx4, Dio1, selenoprotein (Seleno) h, Selenop and Selenou in the liver, Gpx4, Dio1, Txnrd1, Txnrd2, Selenoh, Selenop and Selenou in the kidney, and Gpx1, Gpx4, Selenoh and Selenou in the pancreas, and the protein levels of GPX4 in the liver and kidney of broilers were influenced (P < 0.05) by added Se levels, and increased quadratically (P < 0.05) with the increase of added Se levels. The estimates of optimal dietary Se levels were 0.07 to 0.36 mg/kg based on the fitted broken-line, quadratic or asymptotic models (P < 0.001) of the aforementioned selenoprotein expression in the plasma, liver and kidney, and 0.09 to 0.46 mg/kg based on the fitted broken-line models (P < 0.001) of the aforementioned selenoprotein expression in the pancreas. The results indicate that the optimal dietary Se levels would be 0.36 mg/kg to support the full expression of selenoproteins in the plasma, liver and kidney, and 0.46 mg/kg to support the full expression of selenoproteins in the pancreas of broilers fed a practical corn-soybean meal diet from 1 to 21 d of age.

目前 NRC 对肉鸡的日粮硒 (Se) 需求量 (0.15 mg/kg) 主要基于 1986 年报告的生长性能数据。硒蛋白在各种组织中的表达。总共 384 只 1 日龄雄性肉鸡（n  = 8 次重复/日粮）饲喂基础玉米-豆粕日粮或添加 0.1、0.2、0.3、0.4 或 0.5 mg Se/kg 形式的基础日粮Na ₂ SeO ₃21 天。使用折线、二次或渐近模型进行回归分析以评估最佳膳食硒水平。血浆、肝脏、肾脏和胰腺中的谷胱甘肽过氧化物酶 (GPX)，血浆、肝脏和胰腺中的碘甲状腺原氨酸脱碘酶 (DIO) 以及肝脏和胰腺中的硫氧还蛋白还原酶 (Txnrd) 的活性，Gpx1、Gpx4的 mRNA 水平, Dio1 ,硒蛋白( Seleno ) h , Selenop和Selenou在肝脏中, Gpx4 , Dio1 , Txnrd1 , Txnrd2 , Selenoh , Selenop和Selenou在肾，和GPX1，Gpx4，Selenoh和Selenou在胰腺，和在肝脏和肉鸡的肾脏GPX4的蛋白水平的影响（P  <0.05）由加入硒的水平，和二次曲线增加（P  <0.05 ) 随着添加硒水平的增加。基于 上述血浆、肝脏和肾脏中硒蛋白表达的拟合折线、二次或渐近模型（P < 0.001），最佳膳食硒水平的估计值为 0.07 至 0.36 mg/kg ，以及 0.09 至 0.46 mg/kg kg 基于拟合的折线模型 ( P < 0.001) 的上述硒蛋白在胰腺中的表达。结果表明，最佳日粮硒水平为 0.36 mg/kg 以支持血浆、肝脏和肾脏中硒蛋白的充分表达，以及 0.46 mg/kg 以支持肉鸡胰腺中硒蛋白的充分表达。 1～21日龄的玉米-豆粕日粮。