Publication:

Lipogenic enzyme activity in growing Rasa Aragonesa lambs

The lipogenic enzyme activity of the following enzymes was studied: Glycerol 3-phosphate dehydrogenase (G3PDH), fatty acids synthetase (FAS), NADP-Malate dehydrogenase (ME) and Glucose 6-phosphate dehydrogenase (G6PDH) in five fat depots (omental, OM; mesenteric, MES; kidney knob and channel, KKC; subcutaneous, SC; intermuscular, IM) in 45 male Rasa Aragonesa lambs divided into three groups of 15 lambs (G12, G24, G36). They were slaughtered respectively at 11.70 ± 0.67; 24.50 ± 0.57 and 35.80 ± 1.74 kg of live weight (LW) and at 32 ± 5; 89 ± 8, and 123 ± 8 days old. The G12 lambs were slaughtered on the day of weaning, having consumed solely their mother's milk; those in the G24 and G36 groups were weaned at 16.20 ± 1.32 and 18.30 ± 2.46 kg LW respectively, were fed from then onward concentrated fodder and barley straw ad libitum until they were slaughtered. Between 24 and 36 kg LW an increase in the activity of the G3PDH and FAS lipogenic enzymes was observed. The increasine the 'de novo' synthesis (FAS) at 36 kg LW was matched by G6PDH activity, which indicates greater use of acetate as a precursor of fatty acids. Furthermore, the maintenance of ME activity during the period studied would indicate that the glucose rate utilization for the fatty acids synthesis was not modified throughout this period.