Measuring energy turnover in the adult swine during feeding of rations with potato starch, potatoes, beets, pressed shreds and coarse fodder as supplements to a basic ration. 1. Energy turnover and energy utilization

25 rations with a wide variation of the content of various carbohydrates (crude fibre 36-185; water-soluble carbohydrates 25-306, starch 272-683 g/kg DM) were fed to male castrates (n = 8) of a live weight between 90 and 180 kg, and energy metabolism was measured. The rations were composed of a cereal basic ration and various feed-stuffs (potato starch-raw and soaked) potatoes (raw and steamed), sugar beet and products from it, maize pellets, dried roughage lucerne, clover, lupin, grass, rye straw meal) as supplements. The digestibility and metabolisability of the energy of the rations ranged between 88 and 62 or 86 and 60% resp. Between 2 and 4% of the consumed energy were lost in urine. The partial utilization of the metabolizable energy of the rations varied between 80% (processed supplement of potato starch) and 52% (supplement of rye straw). The rations with supplements of dried roughage were relatively well energetically utilized-between 63 and 70%. A regressively calculated difference of 17%-units was regressively calculated between the utilization of metabolizable energy of either precaecal or postileal origin.