1. This study was conducted to determine the effect of different sources of selenium (Se) on breast and liver tissue deposition, apparent metabolisable energy (AME), growth performance and antioxidant status of broilers, measured as Se content in liver and breast tissues and glutathione peroxidase (GSH-Px) in blood, when used in 0–35 d broiler chicken diets.

2. A total of 200 male Ross 308 broilers were used in the feeding trial, which comprised two dietary phases, a starter from 0 to 21 d and finisher from 21 to 35 d of age. Four treatments with 10 replications each were used. A control diet (C) was formulated that was sufficient in protein and energy (230 and 215 g/kg of crude protein and 12.67 and 13.11 MJ/kg of metabolisable energy, respectively), for both phases, but contained background Se only from the feed ingredients. Diet 2 (IS) was supplemented with 10.35 g/t inorganic, elemental source of Se. Diet 3 (SY) was supplemented with 136.36 g/t selenised yeast, an organic source derived from Saccharomyces cerevisiae. Diet 4 (SS) was supplemented with 0.666 g/t sodium selenite, an inorganic source.

3. Birds fed the SY diet consumed less and weighed less than those fed IS or C (P < 0.05; 0–35 d of age), but there was no difference compared to birds fed SS diets. There were no differences in FCR or dietary AME between broilers fed different Se sources. All diets containing supplementary Se increased concentrations in the liver and breast muscle, and for GSH-Px levels in blood compared to birds fed the C diet (P < 0.001). Birds fed SY diets had greater Se levels in liver and breast tissues compared to birds fed any of the other diets (P < 0.001).

4. Diets supplemented with Se had variable effects on broiler growth performances and antioxidant status. Feeding Se from a yeast source has higher transfer into breast tissues. Feeding different sources and levels of Se to birds in a more challenging situation to induce oxidative stress may bring more conclusive results.

1. 本研究旨在确定不同来源的硒 (Se) 对肉鸡乳房和肝脏组织沉积、表观代谢能 (AME)、生长性能和抗氧化状态的影响，以肝脏和乳房组织中的硒含量和当用于 0-35 天的肉鸡日粮时，血液中的谷胱甘肽过氧化物酶 (GSH-Px)。

2. 饲喂试验共使用 200 头雄性罗斯 308 肉鸡，包括两个日粮阶段，从 0 日至 21 日龄的开食期和 21 日至 35 日龄的育肥期。使用四个处理，每个处理 10 个重复。为两个阶段配制了足够蛋白质和能量（粗蛋白分别为 230 和 215 g/kg，代谢能分别为 12.67 和 13.11 MJ/kg）的对照饮食 (C)，但仅含有来自饲料成分。日粮 2 (IS) 中添加了 10.35 g/t 无机元素硒。日粮 3 (SY) 添加了 136.36 g/t 硒化酵母，这是一种来自酿酒酵母的有机来源。日粮 4 (SS) 中添加了 0.666 g/t 亚硒酸钠，这是一种无机来源。

3. 饲喂 SY 日粮的鸡只比饲喂 IS 或 C 的鸡只消耗更少且体重更轻（P < 0.05；0-35 日龄），但与饲喂 SS 日粮的鸡只相比没有差异。饲喂不同硒源的肉鸡之间的 FCR 或日粮 AME 没有差异。与饲喂 C 日粮的鸡相比，所有添加硒的日粮都增加了肝脏和胸肌中的浓度，以及血液中的 GSH-Px 水平（P < 0.001）。与饲喂任何其他日粮的鸟相比，饲喂 SY 日粮的鸟的肝脏和乳房组织中的硒水平更高（P < 0.001）。

4. 添加硒的日粮对肉鸡生长性能和抗氧化状态有不同的影响。从酵母来源喂养硒具有更高的转移到乳房组织中。在更具挑战性的情况下向鸟类喂食不同来源和水平的硒以诱导氧化应激可能会带来更确凿的结果。