Laboratory of Gastrointestinal Microbiology, Nanjing Agricultural University, 210095, Nanjing, China.
Amino Acids. 2012 Jul;43(1):233-44. doi: 10.1007/s00726-011-1067-z. Epub 2011 Sep 18.
We recently reported that bacteria from the pig small intestine rapidly utilize and metabolize amino acids (AA). This study investigated the effect of L-arginine on the utilization of AA by pure bacterial strains (Streptococcus sp., Escherichia coli and Klebsiella sp.) and mixed bacterial cultures derived from the pig small intestine. Bacteria were incubated at 37°C for 3 h in anaerobic AA media containing 0-5 mmol/L of arginine to determine the effect of arginine on the bacterial utilization of AA. Amino acids in the medium plus cell extracts were analyzed by high-performance liquid chromatography. Results indicated concentration-dependent increases in the bacterial utilization of arginine and altered fluxes of arginine into ornithine and citrulline in the bacteria. Net glutamine utilization increased in pure bacterial strains with increased concentrations of arginine. With the addition of arginine, net utilization of threonine, glycine, phenylalanine and branched-chain AA increased (P<0.05) in Streptococcus sp. and Klebsiella sp., but decreased in E. coli. Net utilization of lysine, threonine, isoleucine, leucine, glycine and alanine by jejunal or ileal mixed bacteria decreased (P<0.05) with the addition of arginine. Complete utilization of asparagine, aspartate and serine were observed in pig small-intestinal bacteria after 3 h of incubation. Overall, the addition of arginine affected the metabolism of the arginine-family of AA and the serine- and aspartate-family of AA in small-intestinal bacteria and reduced the utilization of most AA in ileal mixed bacteria. These novel findings indicate that arginine exerts its beneficial effects on swine nutrition partially by regulating AA utilization and metabolism in the small-intestinal microbiota.
我们最近报道称，猪小肠中的细菌能够迅速利用和代谢氨基酸（AA）。本研究旨在探讨 L-精氨酸对源自猪小肠的纯细菌菌株（链球菌、大肠杆菌和克雷伯氏菌）和混合细菌培养物利用 AA 的影响。将细菌在 37°C 下于厌氧 AA 培养基中孵育 3 小时，其中含有 0-5mmol/L 的精氨酸，以确定精氨酸对细菌利用 AA 的影响。通过高效液相色谱法分析培养基中氨基酸和细胞提取物。结果表明，细菌对精氨酸的利用呈浓度依赖性增加，并且精氨酸转化为鸟氨酸和瓜氨酸的通量发生改变。随着精氨酸浓度的增加，纯细菌菌株中的谷氨酰胺净利用率增加。添加精氨酸后，链球菌和克雷伯氏菌中的苏氨酸、甘氨酸、苯丙氨酸和支链 AA 的净利用率增加（P<0.05），而大肠杆菌中的净利用率降低。添加精氨酸后，回肠和空肠混合细菌中赖氨酸、苏氨酸、异亮氨酸、亮氨酸、甘氨酸和丙氨酸的净利用率降低（P<0.05）。在 3 小时孵育后，猪小肠细菌完全利用了天冬酰胺、天冬氨酸和丝氨酸。总之，添加精氨酸影响了小肠细菌中精氨酸族 AA 和丝氨酸-天冬氨酸族 AA 的代谢，并降低了回肠混合细菌中大多数 AA 的利用率。这些新发现表明，精氨酸通过调节小肠微生物群中 AA 的利用和代谢，对猪的营养产生有益影响。
