Effects of dietary non-phytate phosphorus on performance, egg quality, and bone traits in laying hens of different...

In diets for laying hens, excessive concentrations of non-phytate phosphorus (NPP) have been associated with disrupted calcium homeostasis, reduced eggshell quality, and an increased risk of osteoporosis. Thus, two experiments were conducted to evaluate the productive performance, egg quality, and bone characteristics of laying hens at different ages fed diets with reduced NPP levels. A total of 120 Lohmann Brown hens at 26 weeks of age (Experiment 1) and 96 hens at 66 weeks of age (Experiment 2) were assigned to a completely randomized design with two dietary treatments: a high NPP level (3.8 and 3.6 g/kg in Experiments 1 and 2, respectively) and a reduced NPP level (2.2 g/kg in both experiments). Experiment 1 consisted of ten replicates with six hens per experimental unit, while Experiment 2 consisted of eight replicates with six hens per experimental unit. Both experiments lasted 102 days. Performance, egg quality, and blood and bone traits were evaluated and analyzed by ANOVA at a 5% significance level. Dietary NPP levels did not affect performance or egg quality in either experiment. In Experiment 1, the 2.2 g/kg NPP reduced NPP intake and serum phosphorus (P), and improved tibia calcium (Ca) and P content (p < 0.05). In Experiment 2, the reduced NPP level reduced NPP intake and improved eggshell thickness, breaking strength, and Seedor index (p < 0.05). In conclusion, dietary NPP can be reduced to 2.2 g/kg without impairing the productive performance or egg quality of laying hens. Moreover, this reduction increases tibia Ca and P content in hens between 26 and 41 weeks of age and enhances eggshell thickness and breaking strength in hens between 66 and 81 weeks of age.