Abstract
Olive cake (OC) was collected from the Al-Jouf area and dried by sunny warm air at average temperature 45 degrees C with continuous stirring until completely dried. Then the OC was included in isocaloric, isonitorgneous diets at 0, 10 and 20%. Moreover, Saccharomyces cerevisiae was added at 0, 0.02 and 0.04%. This resulted in 3 (OC levels) x 3 (yeast concentrations) = 9 treatments. Each treatment was represented by eight replicates of three laying hens each. The diets were fed to laying hens during 40-56 weeks of age. Body weight change, laying performance, egg quality, blood biochemical constituents and reproductive organs were investigated. Including olive cake in laying hens diets up to 20% did not negatively affect performance and egg quality, but it increased feed intake and impaired FCR compared with control group (0% OC). Also, inconsistent effect on blood constituents and proportionally effects on abdominal fat and ovary were noted. Yeast supplementation at 0.04% to laying hens diets containing 10 and 20% OC induced an increase in feed intake and impaired FCR, respectively. In addition, yeast supplementation to 10 and 20% OC diets resulted in higher abdominal fat and ovary ratios compared with their respective groups on OC-free diet. It could be concluded that, olive cake could be used in laying hens diets up to 20% without deleterious effects on laying performance, egg quality and health status.