Intramuscular Lipids and Triglyceride Structures in Range and Feedlot Steers

Abstract

Longissimus muscle of feedlot steers contained less moisture and more triglycerides (TG) but similar amounts of cholesterol and lipid phosphorus when compared to muscle of range steers. A 100-g portion of the muscle from feedlot steers provided more of all fatty acids analyzed except iso-and anteiso-tridecanoic and pentadecanoic acids (br 13:0, br 15:O) and octadecatrienoic acid (18:3). Structures of the intramuscular TG were not influenced by dietary treatment. Medium chain saturated acids (1O:O to 15:O) were distributed throughout all 3 positions, 16:0 predominated in the sn-1 position, 18:0 and 20:0 in the sn-1 and ~2-3 positions. Br 13:0 and br 15:0 predominated in the sn-2 position and were essentially absent from the sn-3 position. Monounsaturated acids, with the exception of trans octadecenoic acid (tram 18:1), were found mainly in the sn-2 and sn-3 positions. Trans 18:l predominated in the sn-1 and sn-3 positions thereby resembling a long chain saturated acid, Octadecadienoic acid (18:2) and 18:3 were about equally divided between positions m-2 and sn-3. Tram 18: 1 comprised 1.9 and 1.3% of total intramuscular fatty acids from range and feedlot steers, respectively. The structures of intramuscular TG, with respect to 18:2 and saturated acids, did not resemble those of native peanut oil which has been reported to be more atherogenic than randomized peanut oil.

Effect of management strategy on growth performance, carcass characteristics, fatty acid composition, and palatability attributes in crossbred steers

“…with HG feeding (Table 3). This agrees with past studies where 14:0 tended to increase with time on grain (Dinius and Cross 1978;Duckett et al 1993) and decrease by forage feeding (Miller et al 1981;Mandell et al 1998a). In the present study, 113 d on grain was apparently not adequate in backgrounded steers for complete turnover from a forage-to a grain-influenced deposition of fatty acids (Rule et al 1997).…”

Nutrient analysis of the Beef Alternative Merchandising cuts

“…Substantial research confirms differences in percent fat for USDA Quality Grade (Choi et al, 1987;Miller et al, 1981). Miller et al (1981) attributed increased total lipid to an increase in tryacylglyceride content.…”

“…Substantial research confirms differences in percent fat for USDA Quality Grade (Choi et al, 1987;Miller et al, 1981). Miller et al (1981) attributed increased total lipid to an increase in tryacylglyceride content. found a positive linear relationship between longissimus marbling and percent fat and a negative linear relationship between longissimus marbling and percent moisture in all muscles studied.…”

“…The difference between range-or grass-finished beef and concentrate-or feedlot-finished beef has received much attention. Research indicates that grain-finished beef has a higher concentration of total lipid and a lower percent moisture than grass-finished beef (Duckett et al, 2009;Miller et al, 1981;Miller et al, 1987;Williams et al, 1983). reported that grass-finished beef had less intramuscular fat with a more yellow appearance, which was attributed to forage diets containing greater concentrations of -carotene.…”

“…Studies suggest that cholesterol values are not different between grass-finished or grain-finished beef Miller et al, 1981;Williams et al, 1983).…”