1. Clinic of Medicine, Faculty of Veterinary Medicine; University of Thessally; Trikalon 224, Karditsa 43100, Greece and Animal Medical Center of Athens, Mesogeion 267 15451 Athens Greece
2. Gastrointestinal Laboratory, Department of Small Animal Clinical Sciences; College of Veterinary Medicine and Biomedical Sciences, Texas A&M University; College Station TX 77843 USA