Utilization of¹⁴C-labelledBacillus subtilisandEscherichia coliby sheep

Abstract

I.Bacillus subtilis and Escherichia coli were grown on 14C-labelled glucose and used for the preparation of labelled whole cells, cell walls, cell contents and peptidoglycan.2. The radioactive samples were injected into the abomasum of sheep and the 14C appearing in expired air, plasma glucose, urine and faeces was determined. Whole cells were also injected into the rumen and the incorporation of 14C into volatile fatty acids was measured.3. All the bacterial preparations, including cell walls, were extensively digested and absorbed.Less than 15 % of the radioactivity was recovered in the faeces. 4.Up to 20% of the radioactivity injected was recovered in expired carbon dioxide with only 2.4-8.1 yo passing through the glucose pool.5. It has been calculated that under the conditions of the experiment 18.5 % of the total glucose entering the body pool of glucose in 24 h was derived from bacterial carbon.Studies with sheep given roughage diets show that the rates of entry of glucose into the body pools of glucose (glucose entry rates) are close to those found in monogastric animals in the postabsorptive state (Annison

Glycoprotein Degradation in the Blind Loop Syndrome

“…These findings are reminiscent of previous studies in cecal and rumen physiology which show membrane mucopolysaccharide transformation into SCFA (33,34). It also explains why the presence of high levels of fasting SCFA in blind loop contents fails to show any increase after administration of a meal rich in carbohydrates (14).…”

The chemical composition of rumen bacteria and cell walls from rumen bacteria

“…The possible contribution of the various bacterial components to the glucose requirements of sheep can be estimated on the basis of the results obtained. If approximately 260 g of bacteria pass out of the rumen per day (Hoogenraad, Hird, White & Leng, 1970) then D-alanine present in the cell wall is likely to contribute no more than 0-2 g glucose. As determined by the methods used, the carbohydrates of the bacterial cell, if they are all glucogenic, could supply up to 20 g glucose.…”

“…This would represent a major contribution to the glucose requirements of sheep. Thus it was found in experiments with 14C-labeIled bacteria (Hoogenraad et al 1970) that preparations low in carbohydrate but high in protein were incorporated into glucose when injected into the alimentary tract of a sheep fed a roughage diet.…”

Studies on the nitrogen compounds of the faeces of dairy cows fed urea as the sole or partial source of nitrogen

“…In successive hydrolyses performed with papain and pepsin it was possible to liberate 37 and 30 % respectively of the amino acids of the insoluble fraction of the faeces of ULP-cows. Hoogenraad and Hird (1970) were able to release 45 % of the total amount of amino acids of the bacterial cell walls with pepsin, and 30 % with chymotrypsin. According to an unpublished study of our laboratory there were 1.6-4.0 X 10 8 living anaerobic bacteria and 3.4 -7.9 x 10 6 aerobic bacteria per g fresh faeces with 0-cows; the corresponding figures with ULP-cows were 3.0 X 10 6 -3.9 X 10 s and 4.2 X 10 6 -2.6 X 10 8 .…”