Torrallardona D, Harris C I, Fuller M F
Rowett Research Institute, Bucksburn, Aberdeen.
Br J Nutr. 1996 Nov;76(5):701-9. doi: 10.1079/bjn19960077.
Four rats were housed in cages with mesh floors; another four rats were housed in tubular anticoprophagy cages, in which they could not turn round to reach their own faeces. Both groups were fed for 6 d on a low-protein diet containing fermentable carbohydrates and 15NH4Cl. At the end of the experiment the rats were killed and their carcasses were homogenized, lysine was isolated by ion-exchange chromatography and its 15N enrichment measured by isotope-ratio mass spectrometry. The 15N enrichment in the lysine of the microbial fraction of faeces and the total amount of lysine in the body were also determined in order to estimate the amount of microbial lysine absorbed. The 15N enrichment in body lysine of non-coprophagic rats was not different from that previously measured in rats given unlabelled NH4Cl, but in coprophagic rats it was significantly higher. The daily absorption of microbial lysine by the coprophagic rats accounted for 20.7 (SE 2.55) mg/kg body weight0-75, but was only 0.5 (SE 1.04) mg/kg body weight0-75 for the non-coprophagic rats. This value was not significantly different from zero. The utilization of microbial amino acids via coprophagy resulted in a higher weight gain (adjusted for intake) in the coprophagic group (15.5 g/6 d) than in the non-coprophagic rats (3.1 g/6 d). It was concluded that, in rats, the utilization of microbial lysine occurred exclusively via coprophagy.
将四只大鼠饲养在带有网眼地板的笼子里；另外四只大鼠饲养在管状防食粪笼子里，在这种笼子里它们无法转身吃到自己的粪便。两组大鼠均用含有可发酵碳水化合物和15NH4Cl的低蛋白饮食喂养6天。实验结束时，将大鼠处死并将其尸体匀浆，通过离子交换色谱法分离赖氨酸，并用同位素比率质谱法测量其15N富集量。还测定了粪便微生物部分赖氨酸中的15N富集量和体内赖氨酸的总量，以估计吸收的微生物赖氨酸量。非食粪大鼠体内赖氨酸的15N富集量与先前给未标记NH4Cl的大鼠测量的值没有差异，但食粪大鼠体内的15N富集量明显更高。食粪大鼠每天吸收的微生物赖氨酸为20.7（标准误2.55）mg/kg体重0-75，但非食粪大鼠仅为0.5（标准误1.04）mg/kg体重0-75。该值与零无显著差异。通过食粪作用利用微生物氨基酸导致食粪组（15.5 g/6天）比非食粪大鼠（3.1 g/6天）体重增加更高（根据摄入量调整）。得出的结论是，在大鼠中，微生物赖氨酸的利用仅通过食粪作用发生。
