2. Materials and methods
This experiment was carried out at the University of Aarhus, Denmark. The Danish Ethical Commission approved the experimental protocol and the animals were handled in accordance with guidelines established by this Commission.
2.1. Animals and housing
Sixty piglets (Danish Landrace × Yorkshire × Duroc) from 20 litters were used. Piglets were weaned at 28 ± 1 d of age and a body weight of 8.7 kg (SD = 1.01) and moved to pens (184 cm × 82 cm, of which 82 cm × 82 cm was slatted) where they were individually housed during the whole study. The animals were allotted on the basis of litter, sex, and initial body weight to each of the dietary treatments. Temperature of the nursery was maintained at 28 °C during the first two weeks, 24 °C during the following two weeks, and 20 °C during the last two weeks of the experiment.