Improved Method for the Determination of Volatile Fatty Acids in Ruminant Blood Plasma

Abstract

A method is described for blood plasma volatile fatty acids using direct steam distillation with an anti-foaming agent. Free fatty acids are collected on a microcondenser prior to gas liquid chromatographic analysis. The method is accurate through a wide range for acetate (.05 to 2.50 μmoles per liter), propionate, isobutyrate, butyrate, and valerate (5.0 to 220.0 μmoles per liter). However, with increasing concentration there is decreasing precision. The low precision at high concentrations is not serious, since precision is good within the physiologic range. Volatile fatty acids from aqueous solutions and those added to sheep and cattle blood plasma were quantitatively recovered. A comparison was made of the volatile fatty acid in the jugular blood of sheep under conditions of fasting and refeeding. © 1971, American Dairy Science Association. All rights reserved.