LOSS OF BODY-FAT IN PIGLETS IN SPITE OF GAIN IN LIVE WEIGHT

The animal material consisted of 28 piglets of Danish Landrace, weighi ng 15-20 kg LW in which the digested nutrients were measured together with the protein and fat balances. The measurements were carried out a s balance experiments with a 7-day preliminary period followed by a 7- day collection period. In the middle of che collection period, a 24-ho ur measurement of the gas exchange was performed by means of an open-a ir circuit respiration unit and the data were used for calculation of heat production and oxidation of nutrients. Three different diets were used providing the piglets with different amounts of energy and prote in. A positive live weight gain was, in all series, combined with gain of protein and loss of body fat. With ME intake of less than or equal to 1.0 MJ/kg(0.75), body fat was mobilized to cover the energy requir ement for growth. In all the series, a minor part (6-19 %) of the CHO- pool was not oxidized but was used for lipogenesis. The oxidation of f at was lower than the fat-pool, the residue being used for formation o f structural lipids.