1. Adaptation Physiology Group, Wageningen University & Research, P.O. Box 338, 6700 AH Wageningen, the Netherlands.
2. Animal Nutrition Group, Wageningen University & Research, P.O. Box 338, 6700 AH Wageningen, the Netherlands.
3. Tereos S.A., R&D Department, Z.I. et portuaire B.P. 32, 67390 Marckolsheim, France.