Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada T6G 2P5.
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada T6G 2P5.
Poult Sci. 2022 May;101(5):101792. doi: 10.1016/j.psj.2022.101792. Epub 2022 Feb 23.
Blood concentration of corticosterone (CORT) is a measure of welfare in feed restricted broiler breeders. The RIA and ELISA have been routinely used for measuring CORT in blood, excreta, and feather. Due to the presence of some confounding factors in the aforementioned colorimetric enzyme reaction methods, some methodological difficulties have been attributed to those assays. The correlation between broiler breeder plasma CORT concentrations, measured using ELISA and a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, was the focus of the current study. A total of 36 broiler breeder pullets were used, of which 30 were randomly assigned to one of 10 unique growth trajectories, and 6 were assigned to an unrestricted group. We designed the growth trajectories using a 3-phase Gompertz growth model with 10 levels of BW gain in the prepubertal and pubertal growth phases, ranging from the breeder-recommended target BW (CON) to 22.5% higher (CON+22.5%), in 2.5% increments. The BW trajectories were applied to each individual bird using a precision feeding (PF) system, which collected BW and feed intake data. The birds were classified based on age at first egg (AFE), and 12 birds each having the highest and lowest AFE was selected for the CORT study. Then median photostimulation BW of the candidate birds was used to define the upper (heavy BW) and lower (standard BW) extremes, and plasma CORT levels were evaluated by ELISA and LC-MS/MS methods from their blood collected at 18, 20, 22, 24, and 26 wk of age. Concentrations of plasma CORT measured using ELISA method were highly correlated (r = 0.95; P < 0.001) with values measured using LC-MS/MS method, validating interchangeably usage of both methods to measure plasma CORT in broiler breeders. Plasma CORT levels were not affected by photostimulation BW or breeders' age, indicating same welfare status between the precision fed high and low BW groups.
血液中皮质酮（CORT）的浓度是衡量限饲肉种鸡福利的指标。放射免疫分析（RIA）和酶联免疫吸附测定（ELISA）已常规用于测量血液、排泄物和羽毛中的 CORT。由于上述比色酶反应方法中存在一些混杂因素，这些检测方法存在一些方法学上的困难。本研究的重点是评估使用 ELISA 和新型液相色谱-串联质谱（LC-MS/MS）方法测量肉种鸡血浆 CORT 浓度的相关性。共使用了 36 只肉种鸡母鸡，其中 30 只随机分配到 10 个独特生长轨迹中的一个，6 只分配到非限制组。我们使用三阶段 Gompertz 生长模型设计了生长轨迹，在青春期前和青春期生长阶段，BW 增益有 10 个水平，范围从推荐的种鸡目标 BW（CON）到 22.5%更高（CON+22.5%），以 2.5%的增量递增。使用精确饲喂（PF）系统将 BW 轨迹应用于每个个体鸡，该系统收集 BW 和采食量数据。根据首次产蛋日龄（AFE）对鸡进行分类，选择 AFE 最高和最低的 12 只鸡进行 CORT 研究。然后，根据候选鸡的中位数光刺激 BW 定义上下限（重 BW）和标准 BW），并使用 ELISA 和 LC-MS/MS 方法从 18、20、22、24 和 26 周龄采集的血液中评估血浆 CORT 水平。使用 ELISA 方法测量的血浆 CORT 浓度与使用 LC-MS/MS 方法测量的浓度高度相关（r=0.95；P<0.001），验证了两种方法可互换用于测量肉种鸡的血浆 CORT。血浆 CORT 水平不受光刺激 BW 或种鸡年龄的影响，表明精确饲喂的高 BW 和低 BW 组之间具有相同的福利状态。
