Absorption of Volatile Acids From the Alimentary Tract of the Sheep and Other Animals

Abstract

1. The concentration of volatile acids in the blood draining the rumen is considerably higher than that of peripheral blood in which little volatile acid, if any, is present. 2. Volatile acid in significant amount is present in blood draining the omasum and the caecum but is absent from blood draining the abomasum and small intestine. 3. Volatile acid is also found in significant concentration in blood draining the caecum or colon of the horse, pig and rabbit. 4. Distillation curves indicate that acetic is the predominant acid present in both the rumen contents and in the blood draining the rumen, but the proportion of acids of higher molecular weight than acetic is greater in the rumen contents than in the blood. The same type of distillation curve is found for material taken from the caecum of the sheep and the large intestine of the horse and pig. 5. The rate of absorption of the sodium salts of acetic, propionic and butyric acids, as judged by the concentrations found in the blood leaving the rumen, appears to be in the order of their molecular weights; acetate is rapidly absorbed, propionate less so, while butyrate is slowly absorbed. 6. The quantity of volatile acid calculated as acetic acid absorbed in an hour from the reticulum and rumen together is estimated to vary from 1 to 5 g., but this value must be regarded as minimal.

Ruminant Nutrition, Dietary Factors Influencing Development of Ruminant Stomach

“…This schedule satisfied the total digestible nutrient (TDN) requirements of the Morrison standard for calves of this age making normal growth. In addition to milk, the calves received gradually increasing amounts of a mineral solution until at 4 weeks of age they were consuming 10 ml. per 100 pounds of live weight daily.…”

The Absorption of Volatile Fatty Acids from the Rumen

“…This allowed observations to be made on the essentially intact rumen in its physiological state. The procedure first used by Barcroft, McAnally & Phillipson (1944) and adopted by Danielli et al (1945) was, however, repeated in some experiments. In these the rumen and its associated organs were isolated from the rest of the alimentary tract by tying off the abomasum just below the omasum, taking care to exclude the epiploic vessels.…”

“…In the older view the change would have been ascribed entirely to the advent of alkaline saliva into the rumen. The second point to be noted is that, while it has been claimed that only small quantities of fatty acids are to be found in the abomasum (Phillipson & McAnally, 1942), and that significant quantities of such acids do not appear in the blood draining the abomasum (Barcroft et al 1944), yet the trials described in part (2) (b) demonstrate the passage of considerable amounts of acid into the abomasum under the conditions in which the experiments were made. SUMMARY 1.…”

“…Total pectin (g. Ca pectate) 7-8 7-6 (a) The validity of the use of pectin as a marker for the measurement of absorption of fatty acids from the rumen A sheep which had been starved for 3 days was anaesthetized with nembutal and the rumen was isolated according to the procedure described by Barcroft et al (1944). A canula was tied into the rumen, the contents siphoned out and the organs thoroughly washed with several lots of warm water.…”

Impact and legacy of the highly cited paper by Blaxter and Clapperton (1965) ‘Prediction of the amount of methane produced by ruminants [Br J Nutr 19, 511–522]’

“…Ruminant animals, including cattle, sheep and goats, are among the most efficient herbivores on earth, by virtue of their gut anatomy and high microbial activity in the foregut compartmentthe reticulorumen, or rumen for short (7) . Fibrous plant materials are broken down by microbial activity to SCFA, principally acetate, propionate and butyrate, that are absorbed from the gut and used by the host animal for energy and growth (8,9) . Methane is a consequence of the anaerobic nature of the rumen fermentation, as it is in other anaerobic habitats (10) .…”