Lipid Metabolism in Lambs as Affected by Fattening Rations of Roughage and Concentrate

Abstract

Two groups of five lambs each were fed high-roughage and high-concentrate rations at fattening levels. Intake on the rations was adjusted so that the groups gained equally. The high-roughage group received more linolenic and less oleic and linoleic acids daily. The levels of liver, serum and muscle triglyceride fatty acids were not different between groups. Liver phospholipid fatty acid levels were higher and serum phospholipid fatty acid levels were lower in the high-roughage group. The high-roughage ration decreased dienoic and increased trienoic acids in the phospholipids of liver, serum and muscle. Esterified cholesterol levels were lower in both the liver and serum of the high-roughage group. The cholesterol esters of the high-roughage group contained less dienoic and more trienoic acids than did those of the other group. There appeared to be more stearic acid in omental and subcutaneous adipose tissues of the high-roughage fed lambs. Total fatty acid levels of intestinal contents did not differ due to treatment. The intestinal contents of lambs fed the high-roughage ration contained less monoenoic and dienoic but more trienoic acids. Also, there appeared to be less monoenoic acids in the bile of this group. There were no dietary effects upon the level of trans-configuration in the fatty acids of liver, serum and muscle triglycerides, liver, serum and muscle phospholipids, omental and subcutaneous tissue lipids, lipids of intestinal contents and bile lipids. The proportions of ruminal acetic, propionic, butyric and valeric acids were not significantly different between groups.