Mortensen P B, Clausen M R, Bonnén H, Hove H, Holtug K
Department of Medicine A, Rigshospitalet, University of Copenhagen, Denmark.
JPEN J Parenter Enteral Nutr. 1992 Sep-Oct;16(5):433-9. doi: 10.1177/0148607192016005433.
The production of short-chain fatty acids and ammonia was measured in 16.6% fecal homogenates from 50 subjects incubated at 37 degrees C for 6 and 24 hours. All 50 homogenates produced ammonia and short-chain fatty acids of any chain length (C2-C5). Incubation for 24 hours with dietary fiber (ispaghula husk or wheat bran), albumin, or glucose (10 mg/mL) increased the short-chain fatty acid production (43.6 +/- 2.8, 45.4 +/- 2.0, 60.3 +/- 3.2, and 65.8 +/- 3.1 mmol/L, respectively) compared with controls (21.4 +/- 1.3 mmol/L). The degradation of different substrates was associated with the production of different amounts of ammonia and short-chain fatty acids. Ispaghula, wheat bran, albumin, and glucose were fermented to acetate (> 2 mmol/L; 24-hour incubations) in 86%, 96%, 98%, and 98% of the homogenates, to propionate in 80%, 76%, 100%, and 68%, and to butyrate in 32%, 94%, 88%, and 54% of the homogenates, respectively. Isobutyrate, valerate, and isovalerate were produced from albumin in all (100%) of the homogenates, but only in 2 to 4% of the homogenates incubated with ispaghula or glucose. Ammonia was always (100%) produced after the addition of albumin and always (98%) consumed (assimilated) when glucose was fermented. Surgery (sigmoid or right- or left-sided colonic resection) did not change the pattern of ammonia and short-chain fatty acid production from these substrates. This study suggests that the different colonic flora from a large number of subjects share general biochemical characteristics, which metabolize different substrates to specific patterns of ammonia and short-chain fatty acids.
在37摄氏度下，对来自50名受试者的16.6%粪便匀浆进行6小时和24小时的孵育，测定短链脂肪酸和氨的生成量。所有50份匀浆均产生氨和任何链长（C2 - C5）的短链脂肪酸。与膳食纤维（车前草籽壳或麦麸）、白蛋白或葡萄糖（10 mg/mL）一起孵育24小时后，短链脂肪酸生成量增加（分别为43.6±2.8、45.4±2.0、60.3±3.2和65.8±3.1 mmol/L），而对照组为（21.4±1.3 mmol/L）。不同底物的降解与不同量的氨和短链脂肪酸的生成有关。在86%、96%、98%和98%的匀浆中，车前草籽壳、麦麸、白蛋白和葡萄糖在24小时孵育后发酵生成乙酸盐（>2 mmol/L），分别有80%、76%、100%和68%的匀浆生成丙酸盐，32%、94%、88%和54%的匀浆生成丁酸盐。在所有（100%）匀浆中，白蛋白可生成异丁酸盐、戊酸盐和异戊酸盐，但与车前草籽壳或葡萄糖孵育的匀浆中只有2%至4%能生成这些物质。添加白蛋白后总是（100%）产生氨，而葡萄糖发酵时总是（98%）消耗（同化）氨。手术（乙状结肠或右侧或左侧结肠切除术）并未改变这些底物产生氨和短链脂肪酸的模式。本研究表明，大量受试者的不同结肠菌群具有共同的生化特征，可将不同底物代谢为特定模式的氨和短链脂肪酸。
