1. Department of Chemistry University of Oslo P.O. Box 1033 Blindern 0315 Oslo Norway
2. Department of Chemistry, Biotechnology and Food Science Norwegian University of Life Sciences 1432 Ås Norway
3. Norsvin SA Storhamargata 44 2317 Hamar Norway
4. Department of Animal and Aquacultural Sciences Norwegian University of Life Sciences 1432 Ås Norway