Phosphorus is an essential mineral element in broiler nutrition. In plant-based diets, phosphorus is predominantly present in the form of phytate phosphorus, which is difficult for non-ruminant animals such as chickens to digest and utilize. Consequently, supplementing diets with exogenous phosphorus sources is a primary method to meet the physiological phosphorus requirements of broilers. However, due to the unique physiological structure of poultry, the absorption of dietary phosphorus presents several challenges, which this article will explore.
Key Points:
Status of feed-grade phosphorus sources
Broiler response to phosphorus supplementation
Current challenges in poultry nutrition
Status of Feed-Grade Phosphorus
Different phosphorus sources vary in chemical composition, properties, and elemental ratios, leading to differences in digestion, absorption, and utilization efficiency. As a conventional phosphorus source in feed production—accounting for over 90% of added phosphorus—calcium hydrogen phosphate (DCP) is widely used but has seen rising costs, making it a significant component alongside protein and energy ingredients. Moreover, DCP is insoluble in water, resulting in low absorption and utilization rates in animals and increased phosphorus excretion into the environment.
Therefore, developing phosphorus sources with low inclusion rates, high biological value, and relatively low cost has become a key focus in phosphorus nutrition research. Monocalcium phosphate (MCP), commonly used by feed manufacturers in the United States and in some aquatic feed production in China, has been shown in numerous studies to be more readily absorbed and utilized than DCP. Mono-dicalcium phosphate (MDCP), a co-crystalline compound of MCP and DCP, represents a novel feed additive combining water-soluble and citrate-soluble phosphate. Plant-derived calcium hydrogen phosphate (PDCP) is produced from inositol industry by-products through acid hydrolysis, lime neutralization, and precipitation. Currently, MCP, MDCP, and PDCP are not yet widely adopted as feed phosphorus sources in China and require further investigation.
Broiler Response to Phosphorus Supplementation
As one of the most economically important meat sources, global broiler production exceeded 22.7 billion birds in 2016, underscoring its significant role in animal agriculture. Due to their relatively short intestinal tract, broilers often exhibit lower nutrient utilization efficiency and higher nutrient concentration in feces, leading to substantial nitrogen and phosphorus excretion.
Phosphorus is not only essential for skeletal and dental development in broilers but also plays vital roles in cellular function, enzyme activity, and metabolic processes. In laying hens, the demand for calcium and phosphorus differs markedly due to eggshell formation. Layer diets typically contain higher calcium and lower phosphorus levels, with a higher calcium-to-phosphorus ratio compared to non-laying poultry. This necessitates precise regulation of available phosphorus in the diet to optimize calcium and phosphorus absorption. Changes in phosphorus sources or levels in laying hens may significantly affect calcium utilization and nitrogen metabolism, subsequently influencing nitrogen excretion.
Currently, the general order of phosphorus bioavailability in animals is: mineral phosphorus sources > plant-based phosphorus sources. With ongoing refinement of mineral phosphorus products, options now extend beyond DCP to include monocalcium phosphate, tricalcium phosphate, and others. Among these, MDCP—a eutectic combination of monocalcium phosphate and DCP—exhibits higher water-soluble phosphorus content and lower pH compared to conventional DCP. Research indicates varying utilization rates among different mineral phosphorus sources, though studies comparing these sources in broilers remain limited.
Current Challenges
Major challenges in the use of phosphorus in animal feed include:
Limited phosphorus resources
Environmental pollution from phosphorus excretion
Low utilization of phytate phosphorus by non-ruminants
These issues highlight the need for high-quality, highly water-soluble phosphorus products. In recent years, advancements in phosphorus production technology have driven rapid growth in the global feed-grade phosphate market. Product categories have diversified from traditional DCP to include monocalcium, dicalcium, and tricalcium phosphate series, with forms evolving from powders to various granular specifications, such as feed-grade dicalcium phosphate granules.
As the third most costly feed ingredient after protein and energy sources, feed-grade phosphorus has garnered significant attention. It plays an indispensable physiological role in animal metabolism and serves as a crucial component in energy transfer and life-sustaining processes.