1. Department of Biochemistry, Institute of Soil Science and Plant Cultivation, ul. Czartoryskich 8, 24-100 Pulawy, Poland; Dipartimento di Scienze Farmaceutiche, Universita degli Studi di Salerno, via Ponte Don Melillo, 84084 Fisciano, Salerno, Italy; and Department of Animal Sciences, Oregon State University, Corvallis, Oregon 97331