Tr. West et al., PALMITATE ESTERIFICATION AND GLYCEROPHOSPHATE ACYLTRANSFERASE ACTIVITY IN ADIPOSE-TISSUE OF GROWING LAMBS, Journal of animal science, 72(1), 1994, pp. 81-86
The purposes of this study were to determine the effects of BW in grow
ing lambs on rates of palmitate esterification (PE) and activity of gl
ycerophosphate acytransferase (GPAT) in subcutaneous and intermuscular
adipose tissue in vitro and to determine the relationship between the
se in vitro measurements and carcass lipid accretion. At 37, 49, 60, a
nd 71 kg of live weight, nine, nine, eight, and seven Columbia-Ramboui
llet-cross ewe lambs, repectively, were slaughtered and adipose tissue
was dissected for glycerolipid biosynthesis assays. One-half of each
carcass was boned, and carcass soft tissue lipid was measured. In both
adipose tissues, PE and GPAT activity were highest at 37 kg (P = .000
1); the greatest accumulation of carcass fat occurred between 37 and 4
9 kg (P = .0001). Differences in PE and GPAT were less well marked bet
ween 49-, 60-, and 71-kg lambs, but both were generally decreased with
increased BW. Significant R(2) from regression of mass and percentage
of carcass fat on either PE, GPAT, or steady-state glycerolipid synth
esis (GLS) were from .29 to .44 (PE), .40 to .58 (GPAT), .50 to .75 (G
LS), and .60 to .77 (PE, GPAT, and GLS combined). Changes in PE, GPAT,
and GLS with BW were consistent with changes in rates of carcass fat
accretion, which indicated a close relationship between glycerolipid b
iosynthesis in vitro and lipid deposition in vivo in growing-finishing
lambs.