Breves G, Hoeller H, Harmeyer J, Martens H
J Anim Sci. 1980 Nov;51(5):1177-81. doi: 10.2527/jas1980.5151177x.
Six 5- to 6-month-old sheep fitted with rumen fistulas and reentrant cannulas in the duodenum and in the ileum were adapted to two dies low in thiamin and containing different percentages of urea nitrogen. The sheep were subjected to seven thiamin balance experiments, with continuous feeding and total collection of duodenal and ideal contents and feces for periods of 6 day each. Thiamin and dry matter were determined in aliquots of collected digesta and feces. Daily thiamin intake was always less than .3 mg, but average daily flow of thiamin into the duodenum was between 1.53 and 3.46 milligrams. Microbial net synthesis of thiamin in the forestomach system was between 1.44 and 3.23 mg/day, so 90 to 96% of thiamin entering the duodenum was of microbial origin. Disappearance of thiamin from the small intestines approximately equaled thiamin net synthesis in the forestomachs, indicating high absorption of microbially produced thiamin. In five experiments, thiamin balance in the large intestines was positive, but no measurements were made of thiamin breakdown within, and absorption from, the large intestines.
选用6只5至6月龄的绵羊，在其瘤胃、十二指肠和回肠处安装瘘管和再入式套管，使其适应两种硫胺素含量低且尿素氮比例不同的日粮。对这些绵羊进行了7次硫胺素平衡实验，持续喂食，并分别在6天的时间段内收集十二指肠内容物、回肠内容物和粪便。对收集的消化物和粪便的等分试样进行硫胺素和干物质测定。每日硫胺素摄入量始终低于0.3毫克，但硫胺素每日流入十二指肠的平均量在1.53至3.46毫克之间。前胃系统中硫胺素的微生物净合成量为每日1.44至3.23毫克，因此进入十二指肠的硫胺素中有90%至96%源自微生物。硫胺素在小肠中的消失量大约等于在前胃中的硫胺素净合成量，这表明微生物产生的硫胺素吸收良好。在5次实验中，大肠中的硫胺素平衡为正值，但未对大肠内硫胺素的分解情况以及从大肠的吸收情况进行测量。
