1. Nutreco Research and Development, P.O. Box 220, 5830 AE, Boxmeer, the Netherlands
2. Animal Nutrition Group, Wageningen University, 6709 PG Wageningen, the Netherlands
3. Leibniz Institute for Farm Animal Biology (FBN), Institute of Muscle Biology and Growth, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany
4. Wageningen UR Livestock Research, P.O. Box 65, 8200 AB, Lelystad, the Netherlands