1. Dipartimento di Scienze animali, della nutrizione e degli alimenti, Università Cattolica del Sacro Cuore, Piacenza, Italy
2. Institute of Animal Science, Physiology Unit, University of Bonn, Bonn, Germany
3. Department of Animal Production, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia
4. Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana, IL, USA