A meta-analysis of the effects of nonphytate phosphorus on broiler performance and tibia ash concentration

Decreasing feed costs while maintaining broiler performance at a high level with minimal environmental pollution has become a major challenge for poultry nutritionists in recent years. In this regard, phosphorus (P) is a nutrient that is problematic. To overcome this, a comprehensive knowledge of the responses of broilers to P is needed and the factors that affect its utilization need better understanding. For this purpose, a meta-analysis was conducted using results published in the literature on the responses of broilers to different levels of nonphytate P (NPP), calcium (Ca), microbial phytase (MP), and vitamin D3 or its metabolites (VD). The effects of Ca, MP, and VD on NPP requirements were investigated. Results showed significant (P <= 0.0001) linear and quadratic effects of NPP on all the responses, viz. average daily gain (ADG), feed intake (FI), feed efficiency (FE), and tibia ash concentration (TA). Results showed the negative effect of high Ca levels on all investigated responses, although these deleterious effects were alleviated when levels of NPP were increased or MP and/or VD added. Synergistic effects of MP and VD on FI and TA were observed. Best performance for all responses was found when MP and VD were added to low or moderate levels of Ca and NPP. Optimization showed higher levels of NPP are required to maximize TA compared to ADG, FI, and FE. Based on our analysis, requirements for NPP were affected mostly by Ca (increased) and MP (decreased), and, to a lesser extent, VD (inconsistent).