www.researchgate.net/publication/...f_laying_hens
Abstract, World's Poultry Science Journal, 2013
This study evaluated the effects of thyme (experiment 1) or oregano (experiment 2) on egg production, feed intake, egg quality and blood parameters of laying hens. In each experiment, a total of 120 sixty-week-old Hy-line Brown laying hens were assigned to the basal control diet or the basal diet supplemented with either 10, 20, or 30 g/kg of thyme or oregano (n = 6 per diet, each replicate consists of 5 birds). Hens were fed experimental diets from 60 to 72 weeks of age. Production performance was measured every four weeks and egg quality characteristics were determined at 72 weeks of age. As all , diets including the control had the same energy and nutrient concentrations, this should not compromise the comparison among the diets. Improvements for egg weight, egg mass and hen-day-egg production% (P<0.01) were observed in both experiments during the periods of (68 to 72 weeks of age). The response was maximized between 10 and 20 mg/kg of either supplemental oregano or thyme. Feed conversion ratio was improved (P<0.05) for thyme and oregano supplemented groups, whereas no changes were observed for egg quality characteristics. Based on the observed improvements of egg weight, egg mass, egg production and feed conversin , either 10 or 20 g/kg diet of thyme or oregano can be recommended as beneficial supplementation levels to laying hen diets. More detailed studies are needed to determine the optimal dietary inclusion level and the minimum eating time in regard to effects on performance and egg quality characteristics.