Bergner H, Simon O, Adam K
Arch Tierernahr. 1978 Jan;28(1):21-9. doi: 10.1080/17450397809428211.
Male Wistar rats (weighing some 80 g at the start of the experiment) were fed diets containing maize gluten as protein carrier and which was supplemented with amino acids (except lysine) in such way that their concentrations came up to the requirement norms. Lysine was gradually supplemented this resulting in 10 diets of different lysine content (1.6-10.6 g lysine/16 g N). On the 7th experimental day, 4 animals of each group were labelled with 14C-lysine and subjected to 2-hour measuring of 14CO2-excretion. On the following day, the animals were injected i.p. 15N-lysine, the urine being collected over 24 hours to determine 15N-frequency in urine. Both 14CO2-excretion and 15N-frequency in urine were found to remain constant at a lysine content of the diet up to 4.5 g/16 g N and rose steeply from 5.8 g lysine/16 N on. Under the experimental conditions chosen the lysine requirement is deduced to be 5 g/16 g N. This method of lysine requirement determination is highly sensitive and exact because it covers the catabolization of the amino acids under study and not so parameters that are known to be influenced by other factors such as growth, N-balance, total N-conversion or CO2-formation. The method can also be applied to metabolic situations not connected with productive performances.
雄性Wistar大鼠（实验开始时体重约80克）被喂食以玉米麸质作为蛋白质载体的日粮，该日粮补充了氨基酸（赖氨酸除外），使其浓度达到需求标准。赖氨酸逐渐补充，从而得到10种不同赖氨酸含量的日粮（1.6 - 10.6克赖氨酸/16克氮）。在实验的第7天，每组4只动物用14C - 赖氨酸标记，并进行2小时的14CO2排泄量测量。在接下来的一天，给动物腹腔注射15N - 赖氨酸，收集24小时尿液以测定尿液中的15N频率。发现当日粮中赖氨酸含量高达4.5克/16克氮时，14CO2排泄量和尿液中的15N频率保持恒定，而从5.8克赖氨酸/16克氮开始则急剧上升。在所选择的实验条件下，推断赖氨酸需求量为5克/16克氮。这种测定赖氨酸需求量的方法高度灵敏且准确，因为它涵盖了所研究氨基酸的分解代谢，而非那些已知受其他因素如生长、氮平衡、总氮转化率或二氧化碳形成影响的参数。该方法也可应用于与生产性能无关的代谢情况。
