Interactive effects of calcium, phosphorus, and exogenous phytase on growth performance and bone ash in broilers under Eimeria or necrotic enteritis infections: a systemic review and meta-analysis

Although several studies have explored the influence of calcium (Ca), phosphorus (P), and exogenous phytase (EP) on growth performance and bone mineralization responses to dietary nonphytate P (nPP) levels in broilers, there remains a gap in meta-analytical research focusing on these factors under Eimeria or necrotic enteritis (NE) infections. To address this gap, we conducted a systematic review and meta-analysis of the relevant literature to shed light on this issue. We found that regardless of infection status, reducing Ca and nPP levels in broiler diets led to decreased body weight gain (BWG), feed intake (FI) and bone ash percentage. Eimeria vaccination reduced BWG and bone ash weight, whereas Eimeria infection severely impacted BWG, FI, feed conversion ratio (FCR), and bone ash weight. However, phytase supplementation increased BWG, bone ash percentage and ash weight. Notably, the efficacy of phytase on bone ash percentage and ash weight were compromised when broilers were infected with Eimeria or necrotic enteritis. Our findings suggest that Ca, nPP, phytase, and infection conditions significantly influence the growth performance and bone mineralization of broilers. The effects of phytase on bone ash weight and ash percentage vary depending on different infection status. Given the complexity of these interrelationships, further research is warranted to deepen our understanding of their combined effects on broiler growth and bone mineralization under Eimeria infections.