diethylether. The fat extraction was carried out in a Soxtec HT-6
apparatus (Tecator, Sweden). Ash was determined by combustion
at 550°C for 16 h. Crude fibre was determined according to
AOAC (1975). Acid-insoluble ash in feed and faeces was determined
by ash combustion prior to boiling the ash in HCl (2 M) for
5 min, filtration and further ash combustion. Both ash combustions
were performed by a stepwise procedure at 100, 300 and
600°C for 1, 2, and 12 h, respectively.