Fatty acid composition of fats of differing melting points extracted from ram subcutaneous tissue

The observation that the subcutaneous fat of pasture-fed Southdown rams consists of two distinct regions is reported. Fatty acid composition of fat from the outer and inner regions of subcutaneous tissue taken from the rib region of eight Southdown rams fed pasture were determined. Relative to the harder inner regions (mean melting point 43.1 degrees C), the softer outer regions (mean melting point 31.8 degrees C) were shown to contain more 9:0-, 15:0-, 17:0-, 17:1-, 18:1-cis and total 18:1 fatty acids; less 14:0-, 16:0-, 18:0- and 18:1-trans fatty acids; and a greater variety and a greater concentration of branched-chain components. Proportions of medium chain-length fatty acids, other than 9:0, did not differ between the layers. The fatty acid contents of serial samples taken at 1-mm intervals through these tissues were determined. Changes in concentrations of components among samples were gradual through the tissues. There was no clear connective tissue sheet, as has been reported for pigs. The inner region of the tissues contains apparently nonrandom fluctuating changes in fatty acid composition.