Thiamin Balance in the Gastrointestinal Tract of Sheep

Abstract

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.

Thiamin Supplementation of an All-Concentrate Diet for Feedlot Steers

“…and there are indications that subclinical deficiencies may occur (Linklater et al 1911, Brent 1976. Loew (1975) Buziassy and Tribe (1960) reported that intrarun'rinal synthesis of thiamin rn sheep was onl1, 2.3 mgrday which is consistent with other calculations of l-3.5 mgi day (Hungate 1966;Barr et al l97l;Breves et al 1980). Naga et al were able to demonstrate that mature sheep fed a purified diet containing urea developed typicai thiamin deficiency symptoms such as general nervousness, repeated teeth gnashing, muscle tremors and gradually increasing polyuria as well as impaired rumen motility after about 7 mo.…”

Microbial thiamin metabolism in the rumen simulating fermenter (RUSITEC): the effect of acidogenic conditions, a high sulfur level and added thiamin

“…Net thiamin production in the RUSITEC was within the range observed in vivo (4-17 pg vitamin BI/g organic matter apparently degraded in the rumen) in sheep (Breves et al 1980) or in cows (Steinberg & Kaufmann, 1977;Breves et al 1981). This indicated that long-term fermentation systems are more effective than short duration models, where no net thiamin production was observed (Olkowski et al 1993).…”

Competition for vitamin B1(thiamin) structures numerous ecological interactions

“…Helliwell et al (2013) conclude that dynamic interactions between organisms have shaped divergent approaches for thiamin synthesis often found in closely related taxa. Animals obtain thiamin through consumption of food, with the known exception of ruminants that absorb thiamin released from ruminal microbes as they are lysed during postruminal digestion (Breves et al 1980(Breves et al , 1981.…”