ABSTRACT

1. This study investigated the oxidative status of broilers fed diets containing selenium (Se) from 14 to 35 d of age and reared at two different constant temperatures. Measurements of oxidative status included blood glutathione peroxidase (GSH-Px) and plasma total antioxidant status (TAS). Other variables included feed intake (FI), weight gain (WG), feed conversion ratio (FCR), Se levels in breast and liver tissue, jejunal villus morphometry, percentage weight of organs in relation to body weight; apparent metabolisable energy adjusted for nitrogen (AMEn); dry matter retention (DMR); fat retention (FR) and nitrogen retention (NR).

2. The experiment started at 14 d of age, when 240 birds were randomly allocated to 48 pens (12 pens in four rooms). Treatments included a control diet 1 (SFC; 209.4 g/kg CP and 12.98 MJ/kg ME and no added Se containing saturated fat); diet 2 (SFSe) the control plus 12.605 mg/kg Se additive; diet 3 (USFC) was a second control diet (208.2 g/kg CP and 13.10 MJ/kg ME with no added Se containing unsaturated fat as rapeseed oil); diet 4 (USFSe) was the latter control plus 12.605 mg/kg Se additive. Two rooms were kept at a standard temperature of 20°C (ST) and two rooms were kept at high temperature of 35°C (HT).

3. A temperature x Se interaction existed for GSH-Px in birds reared at ST (P < 0.05), and these birds had the highest levels of Se in liver tissue (P < 0.05). Fat x Se interactions were evident in breast tissue with highest levels in USFSe (P < 0.05). Adding Se improved jejunal VH: CD in USFSe fed birds (P < 0.001).

4. Birds reared at ST had higher FI and WG than those reared at HT (P < 0.001), and had lower FCR than those reared at HT (P < 0.05). AMEn (MJ/kg DM) and FR were higher in birds fed USF diets, and lowest in birds fed SF (P < 0.50 and P < 0.001 respectively). NR was highest in birds raised at ST (P < 0.50).

5. Broiler growth performance was reduced by HT. Oxidative status and Se in liver tissue was improved by adding Se in both diets.

摘要

1. 本研究调查了饲喂含硒 (Se) 日粮并在两种不同恒温条件下饲养的 14 至 35 日龄肉鸡的氧化状态。氧化状态的测量包括血液谷胱甘肽过氧化物酶 (GSH-Px) 和血浆总抗氧化状态 (TAS)。其他变量包括采食量（FI）、增重（WG）、饲料转化率（FCR）、乳房和肝脏组织中的硒水平、空肠绒毛形态学、器官重量相对于体重的百分比；针对氮调整的表观代谢能（AMEn）；干物质保留（DMR）；脂肪潴留（FR）和氮潴留（NR）。

2. 实验从 14 日龄开始，当时 240 只鸡被随机分配到 48 个围栏（四个房间 12 个围栏）。处理包括对照饮食 1（SFC；209.4 g/kg CP 和 12.98 MJ/kg ME，不添加含饱和脂肪的 Se）；饮食 2 (SFSe) 对照加 12.605 mg/kg Se 添加剂；日粮 3 (USFC) 是第二个对照日粮（208.2 g/kg CP 和 13.10 MJ/kg ME，不添加作为菜籽油的含有不饱和脂肪的 Se）；饮食 4 (USFSe) 是后者对照加 12.605 mg/kg Se 添加剂。两个房间保持在 20°C (ST) 的标准温度，两个房间保持在 35°C (HT) 的高温。

3.在ST饲养的鸡只中GSH-Px存在温度x Se相互作用（P < 0.05），这些鸡的肝脏组织中Se含量最高（P < 0.05）。乳房组织中脂肪 x Se 相互作用明显，USFSe 水平最高（P < 0.05）。添加硒改善了 USFSe 喂养的鸡的空肠 VH: CD (P < 0.001)。

4. ST饲养的鸡的FI和WG高于HT饲养的鸡(P < 0.001)，FCR低于HT饲养的(P < 0.05)。AMen (MJ/kg DM) 和 FR 在饲喂 USF 日粮的禽类中较高，而在饲喂 SF 的禽类中最低（分别为 P < 0.50 和 P < 0.001）。NR 在 ST 饲养的鸡只中最高（P < 0.50）。

5. HT 降低了肉鸡的生长性能。通过在两种饮食中添加硒来改善肝组织中的氧化状态和硒。