1. School of Food Science; Washington State University; Pullman Washington 99164-6376 USA
2. Animal Sciences; University of Zawia; Zawia 00218 Libya
3. Department of Mathematics and Statistics; Washington State University; Pullman Washington 99164-3113 USA
4. Department of Horticulture; Washington State University; Pullman Washington 99164 USA
5. Department of Biological Systems Engineering; Washington State University; Pullman Washington 99164-6120 USA