Effects of supplemental lipids on leptin levels and fatty acid composition of bovine adipose depots

Abstract

Lipid was supplied to feedlot cattle diets as either corn oil or rumen-protected conjugated linoleic acid (CLA) for two specific treatment periods of 32 d or 60 d prior to harvest. Thirty-six heifers were fed one of three diets: 1) control, 2) 4% corn oil, or 3) 2% rumen protected CLA. The cis-9, trans-11 CLA isomer has been shown to be a potent anticarcinogen. Leptin is a 16kDa protein secreted by adipocytes that serves as a circulating signal of whole body energy homeostasis. Supplementing lipid to finishing cattle diets altered fatty acid composition of tissues and increased CLA deposition; however, changes were variable between adipose depots as well as length of supplementation. Serum leptin levels were not affected by dietary treatment. Animals supplemented with corn oil contained higher amounts of leptin in adipose tissues. Supplementing lipid to finishing diets did not alter feedlot performance or carcass characteristics.