Heijnen M L, Beynen A C
Department of Human Nutrition, Wageningen Agricultural University, Wageningen, The Netherlands.
J Nutr. 1997 Sep;127(9):1828-32. doi: 10.1093/jn/127.9.1828.
To study the effect of resistant starch (RS) on the route of nitrogen excretion, we fed three groups of six cannulated piglets each a diet containing either uncooked resistant starch (RS2 ), retrograded resistant starch (RS3 ) or glucose. The use of piglets with a cannula at the end of the ileum allowed measurement of the amount of nitrogen that entered the colon. Ileal digesta, urine and feces were collected quantitatively and weighed, and dry matter, starch and nitrogen content were determined. We hypothesized that RS2 would lower colonic absorption of nitrogen when compared with RS3 , because RS2 may be more fermentable than RS3 , thus trapping more nitrogen in bacteria. The piglets fed RS3 had a significantly higher production of ileal digesta and feces than the piglets fed glucose or RS2 . In the piglets fed RS2 , 44% of the amount of RS fed was recovered in the ileal digesta; in the piglets fed RS3 , 71% was recovered. Thus, more fermentable material entered the colon in the RS3 -fed piglets than in the RS2 -fed piglets. Virtually no starch was recovered in the feces of any dietary group. Replacement of glucose by either RS2 or RS3 did not affect nitrogen retention but increased fecal nitrogen excretion. Compared with glucose, RS3 but not RS2 reduced urinary nitrogen excretion, mainly in the form of urea, and reduced the amount of nitrogen absorbed by the colon when expressed as a percentage of the amount of nitrogen entering the colon. This study provides evidence that RS3 , but not RS2 , shifts nitrogen excretion from urine to feces in cannulated piglets.
为研究抗性淀粉（RS）对氮排泄途径的影响，我们给三组仔猪（每组6头，均安装了套管）分别饲喂含未煮熟抗性淀粉（RS2）、回生抗性淀粉（RS3）或葡萄糖的日粮。使用在回肠末端安装了套管的仔猪，可测量进入结肠的氮量。定量收集回肠消化物、尿液和粪便并称重，测定干物质、淀粉和氮含量。我们假设，与RS3相比，RS2会降低结肠对氮的吸收，因为RS2可能比RS3更易发酵，从而使更多氮困在细菌中。饲喂RS3的仔猪回肠消化物和粪便的产量显著高于饲喂葡萄糖或RS2的仔猪。在饲喂RS2的仔猪中，所喂RS量的44%在回肠消化物中回收；在饲喂RS3的仔猪中，这一比例为71%。因此，与饲喂RS2的仔猪相比，饲喂RS3的仔猪有更多可发酵物质进入结肠。实际上，任何日粮组的粪便中均未检测到淀粉。用RS2或RS3替代葡萄糖不影响氮潴留，但增加了粪便氮排泄。与葡萄糖相比，RS3而非RS2减少了尿氮排泄，主要是以尿素的形式，并降低了结肠吸收的氮量（以进入结肠的氮量的百分比表示）。本研究提供了证据，表明在安装了套管的仔猪中，RS3而非RS2使氮排泄从尿液转移至粪便。
