Effect of Purified Diets on the Fatty Acid Composition of Sheep Tallow

Abstract

The tallow from sheep fed purified diets contained less stearate and more oleate than tallow from either sheep fed haygrain diets or grazing animals. In some instances, the altered fatty acid distribution was sufficient to result in a tallow that was a liquid at room temperature. It is probable that less hydrogenation of unsaturated fatty acids was carried out by the rumen microorganisms of the sheep fed the purified diet, because the stearate level of the lipid of the rumen contents was appreciably less than that of the hayfed animals. A high content of transacids in the dietary fat resulted in high levels of transacids in the sheep tallow irrespective of the remainder of the diet, indicating the resistance of the transisomers to hydrogenation by the rumen flora.