Bergner H, Krieghoff E
Arch Tierernahr. 1975 Aug;25(6):411-20. doi: 10.1080/17450397509423205.
Experimental rats (weighing 50-100 gm) received semisynthetic diets containing 8%, 10%, or 12% of crude protein (Soya protein). These were supplemented with graded amounts of L- or DL methionine. After a 5-day feeding period the rats were injected 35S methionine. Subsequently, the levels of urinary 35S excretion were determined over a period of 4 days after methionine injection. The level of urinary 35S excretion was found to be clearly increased if methionine supplementation exceeded the methionine requirements of the animals. Supplementation with 0.15% methionine was just enough for diets containing 8-10% crude protein. 0.2% methionine had to be supplemented to meet the methionine requirements of the animals if the diet contained 12% crude protein. Requirements for the content of sulfur-containing amino acids in the protein were shown to be independent of the protein content of the diet, and were found to vary between 4.4% and 4.7% of the crude protein. The needs for methionine supplementation were independent of the fact whether L methionine or DL methionine was added. It is definite advantage of the present method that methionine demands are determined in close correlation with metabolic processes, including the maintenance metabolism.
实验大鼠（体重50 - 100克）接受含有8%、10%或12%粗蛋白（大豆蛋白）的半合成日粮。这些日粮添加了不同剂量的L - 或DL - 蛋氨酸。经过5天的饲喂期后，给大鼠注射35S蛋氨酸。随后，在注射蛋氨酸后的4天内测定尿中35S的排泄水平。如果补充的蛋氨酸超过动物对蛋氨酸的需求，尿中35S的排泄水平会明显升高。对于含有8 - 10%粗蛋白的日粮，补充0.15%的蛋氨酸就足够了。如果日粮含有12%的粗蛋白，则必须补充0.2%的蛋氨酸以满足动物对蛋氨酸的需求。蛋白质中含硫氨基酸的需求量与日粮的蛋白质含量无关，且发现其占粗蛋白的比例在4.4%至4.7%之间变化。补充蛋氨酸的需求与添加的是L - 蛋氨酸还是DL - 蛋氨酸这一事实无关。本方法的一个明显优点是，蛋氨酸需求量的测定与包括维持代谢在内的代谢过程密切相关。
