Broiler physiological response to low phosphorus diets at different stages of production

Phosphorus (P) inclusion in broiler diets needs to meet the physiological demands at a specific developmental stage to ensure the performance, health, and welfare of the birds and minimize nutrient losses. Toward a more efficient utilization of P in broiler husbandry, a timed nutritional conditioning strategy might enhance the endogenous mechanisms of mineral homeostasis and thus reduce dietary P supply of mineral sources. In this study, following a variable P supply in the starter phase, the effects of a dietary P depletion of broiler chickens were investigated at different developmental stages. Physiological adaptation mechanisms were elucidated based on zootechnical performance, endocrine parameters, regulation of intestinal P transport, bone characteristics, and health aspects. The results revealed a marked response to P depletion at the earliest developmental phase, after which indications of effective compensatory mechanism were detectable with advancing ages. Potential mechanisms that enable broilers to maintain mineral homeostasis primarily include endocrine control mediated by calcitriol actions, as well as intestinal P uptake and mineral mobilization from the bone. Conclusively, the precise timing, duration, and extent of a P depletion strategy in the broiler chicken might be considered for optimized nutrient utilization.