1. Department of Animal Science, Aarhus University, Foulum, DK-8830 Tjele, Denmark
2. INRA, UMR1348, PEGASE, F-35590 Rennes, France
3. Pig Research Centre, Agro Food Park 15, DK-8200 Aarhus N, Denmark
4. Ajinomoto Eurolysine S.A.S., F-75817 Paris Cedex 17, France