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.