1. Department of Paraclinical Sciences , Faculty of Veterinary Medicine, , Ås N-1432 , Norway
2. Norwegian University of Life Sciences , Faculty of Veterinary Medicine, , Ås N-1432 , Norway
3. Department of Animal and Aquacultural Sciences , Faculty of Biosciences, , Ås N-1432 , Norway
4. Norwegian University of Life Sciences , Faculty of Biosciences, , Ås N-1432 , Norway
5. Department of Food Science and Nutrition, University of Minnesota , St Paul, MN 55108 , United States
6. Department of Animal Science, University of Minnesota , St Paul, MN 55108 , United States