Buyse Johan, Geypens Benny, Malheiros Ramon Dinez, Moraes Vera Maria, Swennen Quirine, Decuypere Eddy
Department of Animal Production, Katholieke Universiteit Leuven, Heverlee, Belgium.
Life Sci. 2004 Sep 17;75(18):2245-55. doi: 10.1016/j.lfs.2004.05.016.
During their relatively short commercial lifespan of six weeks, broiler chickens undergo very pronounced age- or body weight-related changes in metabolic rate and body composition. The present study was aimed to assess the age-related changes in glucose oxidation rate of broiler chickens by using 13C-labeled glucose. The methodology for this breath test needed to be established first. Broiler chickens aged from two to six weeks were placed in open-circuit respiration cells and received a single intubation of U-13C6-glucose, followed by breath sampling for 4 hours and mass spectrometric analysis of 13C: 12C ratio in the exhaled air. Simultaneously, CO2 concentration in the respiration cell air was continuously monitored in order to calculate the cumulative percentage dose recovery (CPDR). With respect to the methodology, an oral dose of 2 mg U-13C6-glucose per kg body weight while maintaining a CO2 in the concentration of 0.4 to 0.5% was considered to be optimal. The three-parameter Gompertz curve fitted the CPDR values very well. Pronounced age-related changes in exogenous glucose oxidation rates in rapidly growing meat-type chickens were assessed. Young broiler chickens spend only a relatively low percentage of ingested glucose for immediate oxidation. In contrast, broiler chickens approaching the age of maximal absolute growth rate oxidize a greater proportion of the recently ingested glucose relative to the non-oxidative disposal pathways. This shift in the exogenous partitioning is discussed in relation to age-dependent changes in glucose turnover, lipid oxidation and deposition and metabolic heat production.
在为期六周的相对较短的商业饲养期内，肉鸡的代谢率和身体组成会随着年龄或体重发生非常显著的变化。本研究旨在通过使用13C标记的葡萄糖来评估肉鸡葡萄糖氧化率的年龄相关变化。首先需要建立这种呼吸测试的方法。将2至6周龄的肉鸡放置在开路呼吸室中，单次插管给予U-13C6-葡萄糖，随后进行4小时的呼气采样，并对呼出气体中的13C:12C比值进行质谱分析。同时，持续监测呼吸室空气中的二氧化碳浓度，以计算累积剂量回收率（CPDR）。关于该方法，每千克体重口服2毫克U-13C6-葡萄糖，同时将二氧化碳浓度维持在0.4%至0.5%被认为是最佳的。三参数Gompertz曲线能很好地拟合CPDR值。评估了快速生长的肉用型鸡中外源葡萄糖氧化率与年龄相关的显著变化。幼龄肉鸡仅将摄入葡萄糖的相对较低比例用于即时氧化。相比之下，接近最大绝对生长率年龄的肉鸡相对于非氧化处置途径，氧化了更大比例的近期摄入葡萄糖。本文讨论了这种外源分配的变化与葡萄糖周转、脂质氧化与沉积以及代谢产热的年龄依赖性变化之间的关系。
