1. Department of Animal Science, Food and Nutrition, Southern Illinois University, Carbondale, IL 62901-4317, USA
2. Physiology, Southern Illinois University, Carbondale, IL 62901-6512, USA
3. Department of Animal Sciences, Purdue University, West Lafayette, IN 47907-2054, USA
4. Department of Chemistry and Biochemistry, Meyers Institute for Interdisciplinary Research in Organic and Medicinal Chemistry, Southern Illinois University, Carbondale, IL 62901-4409, USA