THE EFFECT OF ENERGY SUPPLY ON THE CONTRIBUTION OF LEAN TISSUE TO TOTAL-BODY PROTEIN MASS IN PIGS SLAUGHTERED AT 100 KG

The effect of energy supply between 45 and 100 kg body weight (BW) on the contribution of lean tissue (muscle plus intermuscular adipose tis sue) to total protein mass was studied in Large White castrated males (cLW), crossbred Pietrain x Large White castrated males (cPPx) and boa rs (bPPx). The pigs were allocated to four energy levels (0.70, 0.80, 0.90 or 1.00 ad libitum) and kept in metabolism cages in experiment 1 or given food ad libitum and kept in individual pens in experiment 2. Daily protein supplies were calculated to be non-limiting for growth a nd identical for all pigs in experiment 1. Temperature was 23 degrees C in both experiments. The pigs were slaughtered at 100 kg BW and phys ically dissected; the body tissues were chemically analysed. Taking in to account housing conditions, the food intake of pigs in experiment 2 corresponded to 1.20 of ad libitum intake of pigs in experiment 1; da ta of both experiments were combined. The energy supply and the type o f pig influenced significantly the protein content of empty BW (eBW) ( 170 g/kg on average), of lean (184 g/kg on average) and non-lean compa rtment (eBW minus lean, 152 g/kg on average), the proportion of total protein deposited in lean (604 g/kg of total protein, on average) but not the protein content in fat-free eBW (209 g/kg on average). The fat -free eBW can be predicted as 4.8 times the body protein mass.