Breed effects on cellularity and lipogenic enzymes in growing Spanish lambs

Abstract

Size and number of adipocytes and lipogenic enzyme activity in different adipose depots in Lacha (L) and Rasa Aragonesa (RA) lambs has been compared. 42 L males were assigned into three different groups and were slaughtered at the following live weights (LW): 11.4 kg (L12), 24.6 kg (L24) and 35.3 kg (L36). Forty-five RA males were also assigned into three groups and were slaughtered at similar LW than L lambs: 11.70 kg (RA12), 24.5 kg (RA24) and 35.8 kg (RA36). L12 and RA12 lambs were fed on ewe milk until they were slaughtered. After weaning, L24, L36, RA24 and RA36 lambs were fed on commercial concentrate and barley straw, both ad libitum, until they were slaughtered. The parameters studied in omental (OM), mesenteric (MES) and perirenal (PR) adipose depots were: the weight of adipose tissue, the number and size of adipocytes and the activity of Glycerol 3-phosphate dehydrogenase (G3PDH), Fatty acid synthetase (FAS), NADP–malate dehydrogenase (MD) and Glucose 6-phosphate dehydrogenase (G6PDH); in subcutaneous (SC) and intermuscular (IM) depots the same parameters were determined except the adipocyte number. Internal adipose tissue weight in RA lambs was higher than in L lambs due to a greater number of adipocytes at 12 kg LW and to larger adipocytes size at 24 and 36 kg LW. Besides the greater adiposity in RA lambs was consistent with a higher G3PDH enzyme activity, which is tightly correlated with triacylglycerol esterification. Nevertheless, FAS activity was higher in L lambs. In conclusion, it is noted that the different intensity of hypertrophy–hyperplasia and enzyme activities observed in the lambs was the cause for the different adiposity that has been found.