Lipids of sheep lymph. Transport from the intestine

Abstract

The thoracic duct of each of 4 sheep was cannulated, enabling lymph to be collected; in addition, lymph was also obtained from the intestinal duct of one of these animals and from the cervical ducts of another. Thoracic-duct lymph contained very much more lipid than did cervical-duct lymph, and it was shown that this lipid originated in lymph draining into the thoracic duct via the intestinal lymph duct. Triglycerides constituted the major lipid component of thoracic-duct lymph and intestinal-duct lymph, and these were characterized by the high proportion of stearic acid that they contained; the amount of stearic acid in daily transport from the gut of four sheep was in the range 5.6-7.4 g. The stearic acid was apparently largely derived from the intestinal absorption of that produced in the rumen by microbial hydrogenation of unsaturated C18 fatty acids of the feed lipids. Analysis of the contents of the upper small intestine of one sheep indicated that, in addition to lipid reaching this part of the alimentary tract in the digesta, lipid was also being contributed to the lumen contents from some endogenous source.