EFFECT OF ENERGY-INTAKE ON THE PERFORMANCE OF DIFFERENT TYPES OF PIG FROM 45 TO 100 KG BODY-WEIGHT .2. TISSUE GAIN

Tile effect of energy supply on physical composition of body weight ga in between 45 and 100 kg was studied in Large White castrated males (c LW), crossbred Pietrain x Large White castrated males (cPPX) and boars (bPPX). The pigs were either given food ad libitum and kept in indivi dual pens in experiment 1, or allocated to four energy levels (0.70, 0 .80, 0.90, and 1.00 ad libitum) and kept in metabolism cages in experi ment 2. Daily protein supplies were calculated to be the same at the f our energy levels within each type of pig and non-limiting for growth. Five additional animals for each type of pig were slaughtered at 45 k g. Daily tissue gain was measured according to the comparative slaught er technique. The daily lean gain increased with metabolizable energy (ME) intake according to a linear-plateau relationship whereas the dai ly fat gain increased linearly. The type of pig significantly affected the slope of the relationship between lean gain and ME intake (from 1 5 to 21 g per extra MJ ME) but not the slope of the relationship betwe en fat gain and ME intake (10 g per extra MJ ME on average). Increased energy intake was associated with increased fatness of body-weight ga in, which was higher in cLW and cPPX than in bPPX.