Simon O, Bergner H, Adam K
Arch Tierernahr. 1977 Dec;27(12):691-700. doi: 10.1080/17450397709426773.
Male Wistar rats (of 60 g live weight) allotted in 10 groups were fed diets with gradually increasing lysine levels ranging from 1.4 to 7.4 g lysine/16 g N. Feed intake was restricted so much that the experimental animals did not change their live weights during the last 3 days of the 8-day experiment period. On the 7th experimental day, 4 animals of each group were injected i.p. 14-C-L-lysine, the 14CO2-excretion being subsequently measured over a period of 2 hours. On the next day, 6 animals of each group were applied an i.p. injected of 15N-L-lysine, the urine being collected over the following 24-hour period to measure the 15N-frequency. Applying both labelling methods, an increased catabolisation of the amino acid was observed after the metabolically necessary lysine requirement had been covered. The methods are very sensitive and revealed, under the experimental conditions chosed, a lysine requirement coverage of about 3 g lysine/16 g N. The possibility of using also 15N-labelled compounds in the metabolism-oriented amino acid requirement determination is likely to facilitate the transfer of the methodology to farm animals and would thus allow to study the amino acid requirement of man. The metabolism-oriented amino acid requirement determination will likewise allow to estimate exact amino acid requirement data under conditions that cannot be rated on the basis of productive yields.
将体重60克的雄性Wistar大鼠分成10组，饲喂赖氨酸水平从1.4克/16克氮逐渐增加到7.4克/16克氮的日粮。限制采食量，使实验动物在8天实验期的最后3天体重不变。在实验第7天，每组4只动物腹腔注射14-C-L-赖氨酸，随后在2小时内测定14CO2的排泄量。次日，每组6只动物腹腔注射15N-L-赖氨酸，在接下来的24小时内收集尿液以测定15N频率。采用这两种标记方法，在满足代谢所需的赖氨酸需求后，观察到氨基酸分解代谢增加。这些方法非常灵敏，在所选择的实验条件下，显示出赖氨酸需求量约为3克/16克氮时需求得到满足。在以代谢为导向的氨基酸需求量测定中使用15N标记化合物的可能性，可能会促进该方法向家畜的转移，从而可以研究人类的氨基酸需求。以代谢为导向的氨基酸需求量测定同样可以在无法根据生产性能进行评估的条件下估计准确的氨基酸需求数据。
