EFFECT OF ENERGY-INTAKE ON THE PERFORMANCE OF DIFFERENT TYPES OF PIG FROM 45 TO 100 KG BODY-WEIGHT .1. PROTEIN AND LIPID DEPOSITION

Between 45 and 100 kg body weight, Large White castrated males (cLW), and crossbred Pietrain x Large White castrated males (cPPX) and boars (bPPX) were either given food ad libitum in experiment 1 or allocated to four energy levels (0.70, 0.80, 0.90, 1.00 ad libitum) in experimen t 2. Daily protein and amino acid supplies were calculated to be non-l imiting for growth. Protein (PD) and lipid no) deposition rates were m easured according to the comparative slaughter technique over the whol e experimental period (experiments I and 2) and according to the nitro gen and energy balance technique at four stages of growth: 48, 64, 79 and 94 kg mean body weight (experiment 2). Average daily gain increase d linearly with metabolizable energy (ME) intake, the slope of the rel ationship being significantly different between types of pig (from +28 to +36 g per additional MJ ME). Daily PD increased with ME intake abo ve maintenance (MEp) according to a linear-plateau relationship in the three types of pig: the slope was significantly affected by type of p ig (from +3.4 to 6.0 g per extra MJ MEp) but not by stage of growth. D aily LD increased linearly with MEp intake; neither the type of pig no r the stage of growth affected its slope (+13.5 g per extra MJ MEp). T he LD/PD ratio in the extra body-weight gain associated with increased energy intake was affected only by the type of pig.