1. Gastrointestinal Laboratory, Department of Small Animal Clinical Sciences, Texas A&M University, College Station, TX, USA
2. Department of Poultry Science and Faculty of Nutrition, Texas A&M University, College Station, TX, USA
3. Veterinary Specialty Hospital, San Diego, CA, USA
4. Image Analysis Laboratory, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA