Larsen F M, Moughan P J, Wilson M N
Department of Chemistry and Biochemistry, Massey University, Palmerston North, New Zealand.
J Nutr. 1993 Nov;123(11):1898-904. doi: 10.1093/jn/123.11.1898.
The effect of dietary fiber viscosity on the excretion of endogenous nitrogen and amino acids from the small intestinal lumen of growing rats was investigated. Rats were fed for 12 d protein-free diets containing 5% cellulose (negligible viscosity) or 5% carboxymethylcellulose of low (20 cP), medium (800 cP) or high (2000 cP) viscosity, as the sole dietary fiber source. As dietary fiber viscosity increased from 0 to 2000 cP, there was a significant (P < 0.05) linear increase in the flow of endogenous nitrogen, aspartic acid, serine, glutamic acid, proline, threonine, glycine, alanine, isoleucine, histidine, valine, methionine, leucine and lysine at the terminal ileum. The amino acid composition of the ileal digesta was unaffected by changes in fiber viscosity. It seems that either endogenous protein of a similar origin was secreted in larger amounts or that the digestion and absorption of endogenous amino acids was inhibited as dietary fiber viscosity increased. There was a significant (P < 0.05) linear increase in the concentration of sialic acids relative to chromic oxide in the small intestinal contents with increasing fiber viscosity, indicating an increase in mucoproteins.
研究了膳食纤维粘度对生长大鼠小肠腔内内源氮和氨基酸排泄的影响。给大鼠喂食含5%纤维素（粘度可忽略不计）或5%低粘度（20厘泊）、中粘度（800厘泊）或高粘度（2000厘泊）羧甲基纤维素的无蛋白日粮12天，作为唯一的膳食纤维来源。随着膳食纤维粘度从0增加到2000厘泊，回肠末端的内源氮、天冬氨酸、丝氨酸、谷氨酸、脯氨酸、苏氨酸、甘氨酸、丙氨酸、异亮氨酸、组氨酸、缬氨酸、蛋氨酸、亮氨酸和赖氨酸流量显著（P<0.05）线性增加。回肠消化物的氨基酸组成不受纤维粘度变化的影响。似乎要么是来源相似的内源蛋白分泌量增加，要么是随着膳食纤维粘度增加，内源氨基酸的消化和吸收受到抑制。随着纤维粘度增加，小肠内容物中唾液酸相对于氧化铬的浓度显著（P<0.05）线性增加，表明粘蛋白增加。
