A study of lipids in commercial feeds

Abstract

Summary and ConclusionsThe total extract, phospholipid, unsaponifiable matter, and total fatty acids were determined on 6 samples each of soybean oil meal, cottonseed oil meal, meat and bone scraps, alfalfa leaf meal, wheat gray shorts with screenings, and whole oats and on 5 samples of barley, using both the 16‐hour anhydrous ether method and a 3+1 alcohol‐ether method of extraction. With the exception of whole oats and barley the total ether soluble extract was considerably greater by alcohol‐ether extraction than by ether extraction, especially so in the case of soybean meal and cottonseed meal. The non‐phospholipid fatty acids, however, showed no significant difference between the two methods of extraction, the differences in total fatty acids being accounted for by the different amounts of phospholipid fatty acids.The total extract is a poor criterion of the lipid feed value of some feeds, especially alfalfa leaf meal and soybean meal. However, the ethyl ether method more nearly approximates the total fatty acid content than does the alcohol ether method of extraction.Much of the total extract cannot be accounted for in the sum of the phopholipid, unsaponifiable matter and fatty acid contents as determined.A method is presented for the determination of phospholipid in plant tissue.The significance of the lipid analysis of the feeds investigated and the relative values of the anhydrous ether and a 3+1 alcohol ether methods of analyses are discussed.